
{*******************************************************}
{                                                       }
{       Borland Delphi Visual Component Library         }
{                                                       }
{       Copyright (c) 1995,99 Inprise Corporation       }
{                                                       }
{*******************************************************}

unit PCGrids;

{$R-,T-,H+,X+}

interface

uses Messages, Windows,  SysUtils, Classes, Graphics, Menus, Controls, Forms,
  StdCtrls, Mask;

const
  MaxCustomExtents = MaxListSize;
  MaxShortInt = High(ShortInt);

type
  EInvalidGridOperation = class(Exception);

  { Internal grid types }
  TGetExtentsFunc = function(Index: Longint): Integer of object;

  TGridAxisDrawInfo = record
    EffectiveLineWidth: Integer;
    FixedBoundary: Integer;
    GridBoundary: Integer;
    GridExtent: Integer;
    LastFullVisibleCell: Longint;
    FullVisBoundary: Integer;
    FixedCellCount: Integer;
    FirstGridCell: Integer;
    GridCellCount: Integer;
    GetExtent: TGetExtentsFunc;
  end;

  TGridDrawInfo = record
    Horz, Vert: TGridAxisDrawInfo;
  end;

  TGridState = (gsNormal, gsSelecting, gsRowSizing, gsColSizing,
    gsRowMoving, gsColMoving);
  TGridMovement = gsRowMoving..gsColMoving;

  { TInplaceEdit }
  { The inplace editor is not intended to be used outside the grid }

  TCustomGrid = class;

  TInplaceEdit = class(TCustomMaskEdit)
  private
    FGrid: TCustomGrid;
    FClickTime: Longint;
    procedure InternalMove(const Loc: TRect; Redraw: Boolean);
    procedure SetGrid(Value: TCustomGrid);
    procedure CMShowingChanged(var Message: TMessage); message CM_SHOWINGCHANGED;
    procedure WMGetDlgCode(var Message: TWMGetDlgCode); message WM_GETDLGCODE;
    procedure WMPaste(var Message); message WM_PASTE;
    procedure WMCut(var Message); message WM_CUT;
    procedure WMClear(var Message); message WM_CLEAR;
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    procedure DblClick; override;
    function DoMouseWheel(Shift: TShiftState; WheelDelta: Integer;
      MousePos: TPoint): Boolean; override;
    function EditCanModify: Boolean; override;
    procedure KeyDown(var Key: Word; Shift: TShiftState); override;
    procedure KeyPress(var Key: Char); override;
    procedure KeyUp(var Key: Word; Shift: TShiftState); override;
    procedure BoundsChanged; virtual;
    procedure UpdateContents; virtual;
    procedure WndProc(var Message: TMessage); override;
    property  Grid: TCustomGrid read FGrid;
  public
    constructor Create(AOwner: TComponent); override;
    procedure Deselect;
    procedure Hide;
    procedure Invalidate; reintroduce;
    procedure Move(const Loc: TRect);
    function PosEqual(const Rect: TRect): Boolean;
    procedure SetFocus; reintroduce;
    procedure UpdateLoc(const Loc: TRect);
    function Visible: Boolean;
    property OnKeyPress;
    property OnExit;
    property ReadOnly;
    property PopupMenu;
    property MaxLength;
  end;

  { TCustomGrid }

  { TCustomGrid is an abstract base class that can be used to implement
    general purpose grid style controls.  The control will call DrawCell for
    each of the cells allowing the derived class to fill in the contents of
    the cell.  The base class handles scrolling, selection, cursor keys, and
    scrollbars.
      DrawCell
        Called by Paint. If DefaultDrawing is true the font and brush are
        intialized to the control font and cell color.  The cell is prepainted
        in the cell color and a focus rect is drawn in the focused cell after
        DrawCell returns.  The state passed will reflect whether the cell is
        a fixed cell, the focused cell or in the selection.
      SizeChanged
        Called when the size of the grid has changed.
      BorderStyle
        Allows a single line border to be drawn around the control.
      Col
        The current column of the focused cell (runtime only).
      ColCount
        The number of columns in the grid.
      ColWidths
        The width of each column (up to a maximum MaxCustomExtents, runtime
        only).
      DefaultColWidth
        The default column width.  Changing this value will throw away any
        customization done either visually or through ColWidths.
      DefaultDrawing
        Indicates whether the Paint should do the drawing talked about above in
        DrawCell.
      DefaultRowHeight
        The default row height.  Changing this value will throw away any
        customization done either visually or through RowHeights.
      FixedCols
        The number of non-scrolling columns.  This value must be at least one
        below ColCount.
      FixedRows
        The number of non-scrolling rows.  This value must be at least one
        below RowCount.
      GridLineWidth
        The width of the lines drawn between the cells.
      LeftCol
        The index of the left most displayed column (runtime only).
      Options
        The following options are available:
          goFixedHorzLine:     Draw horizontal grid lines in the fixed cell area.
          goFixedVertLine:     Draw veritical grid lines in the fixed cell area.
          goHorzLine:          Draw horizontal lines between cells.
          goVertLine:          Draw vertical lines between cells.
          goRangeSelect:       Allow a range of cells to be selected.
          goDrawFocusSelected: Draw the focused cell in the selected color.
          goRowSizing:         Allows rows to be individually resized.
          goColSizing:         Allows columns to be individually resized.
          goRowMoving:         Allows rows to be moved with the mouse
          goColMoving:         Allows columns to be moved with the mouse.
          goEditing:           Places an edit control over the focused cell.
          goAlwaysShowEditor:  Always shows the editor in place instead of
                               waiting for a keypress or F2 to display it.
          goTabs:              Enables the tabbing between columns.
          goRowSelect:         Selection and movement is done a row at a time.
      Row
        The row of the focused cell (runtime only).
      RowCount
        The number of rows in the grid.
      RowHeights
        The hieght of each row (up to a maximum MaxCustomExtents, runtime
        only).
      ScrollBars
        Determines whether the control has scrollbars.
      Selection
        A TGridRect of the current selection.
      TopLeftChanged
        Called when the TopRow or LeftCol change.
      TopRow
        The index of the top most row displayed (runtime only)
      VisibleColCount
        The number of columns fully displayed.  There could be one more column
        partially displayed.
      VisibleRowCount
        The number of rows fully displayed.  There could be one more row
        partially displayed.

    Protected members, for implementors of TCustomGrid descendents
      DesignOptionBoost
        Options mixed in only at design time to aid design-time editing.
        Default = [goColSizing, goRowSizing], which makes grid cols and rows
        resizeable at design time, regardless of the Options settings.
      VirtualView
        Controls the use of maximum screen clipping optimizations when the
        grid window changes size.  Default = False, which means only the
        area exposed by the size change will be redrawn, for less flicker.
        VirtualView = True means the entire data area of the grid is redrawn
        when the size changes.  This is required when the data displayed in
        the grid is not bound to the number of rows or columns in the grid,
        such as the dbgrid (a few grid rows displaying a view onto a million
        row table).
     }

  TGridOption = (goFixedVertLine, goFixedHorzLine, goVertLine, goHorzLine,
    goRangeSelect, goDrawFocusSelected, goRowSizing, goColSizing, goRowMoving,
    goColMoving, goEditing, goTabs, goRowSelect,
    goAlwaysShowEditor, goThumbTracking);
  TGridOptions = set of TGridOption;
  TGridDrawState = set of (gdSelected, gdFocused, gdFixed);
  TGridScrollDirection = set of (sdLeft, sdRight, sdUp, sdDown);

  TGridCoord = record
    X: Longint;
    Y: Longint;
  end;

  TGridRect = record
    case Integer of
      0: (Left, Top, Right, Bottom: Longint);
      1: (TopLeft, BottomRight: TGridCoord);
  end;

  TSelectCellEvent = procedure (Sender: TObject; ACol, ARow: Longint;
    var CanSelect: Boolean) of object;
  TDrawCellEvent = procedure (Sender: TObject; ACol, ARow: Longint;
    Rect: TRect; State: TGridDrawState) of object;

  TCustomGrid = class(TCustomControl)
  private
    FAnchor: TGridCoord;
    FBorderStyle: TBorderStyle;
    FCanEditModify: Boolean;
    FColCount: Longint;
    FColWidths: Pointer;
    FTabStops: Pointer;
    FCurrent: TGridCoord;
    FDefaultColWidth: Integer;
    FDefaultRowHeight: Integer;
    FFixedCols: Integer;
    FFixedRows: Integer;
    FFixedColor: TColor;
    FGridLineWidth: Integer;
    FOptions: TGridOptions;
    FRowCount: Longint;
    FRowHeights: Pointer;
    FScrollBars: TScrollStyle;
    FTopLeft: TGridCoord;
    FSizingIndex: Longint;
    FSizingPos, FSizingOfs: Integer;
    FMoveIndex, FMovePos: Longint;
    FHitTest: TPoint;
    FInplaceEdit: TInplaceEdit;
    FInplaceCol, FInplaceRow: Longint;
    FColOffset: Integer;
    FDefaultDrawing: Boolean;
    FEditorMode: Boolean;
    function CalcCoordFromPoint(X, Y: Integer;
      const DrawInfo: TGridDrawInfo): TGridCoord;
    procedure CalcDrawInfoXY(var DrawInfo: TGridDrawInfo;
      UseWidth, UseHeight: Integer);
    function CalcMaxTopLeft(const Coord: TGridCoord;
      const DrawInfo: TGridDrawInfo): TGridCoord;
    procedure CancelMode;
    procedure ChangeGridOrientation(RightToLeftOrientation: Boolean);
    procedure ChangeSize(NewColCount, NewRowCount: Longint);
    procedure ClampInView(const Coord: TGridCoord);
    procedure DrawSizingLine(const DrawInfo: TGridDrawInfo);
    procedure DrawMove;
    procedure FocusCell(ACol, ARow: Longint; MoveAnchor: Boolean);
    procedure GridRectToScreenRect(GridRect: TGridRect;
      var ScreenRect: TRect; IncludeLine: Boolean);
    procedure HideEdit;
    procedure Initialize;
    procedure InvalidateGrid;
    procedure InvalidateRect(ARect: TGridRect);
    procedure ModifyScrollBar(ScrollBar, ScrollCode, Pos: Cardinal;
      UseRightToLeft: Boolean);
    procedure MoveAdjust(var CellPos: Longint; FromIndex, ToIndex: Longint);
    procedure MoveAnchor(const NewAnchor: TGridCoord);
    procedure MoveAndScroll(Mouse, CellHit: Integer; var DrawInfo: TGridDrawInfo;
      var Axis: TGridAxisDrawInfo; Scrollbar: Integer; const MousePt: TPoint);
    procedure MoveCurrent(ACol, ARow: Longint; MoveAnchor, Show: Boolean);
    procedure MoveTopLeft(ALeft, ATop: Longint);
    procedure ResizeCol(Index: Longint; OldSize, NewSize: Integer);
    procedure ResizeRow(Index: Longint; OldSize, NewSize: Integer);
    procedure SelectionMoved(const OldSel: TGridRect);
    procedure ScrollDataInfo(DX, DY: Integer; var DrawInfo: TGridDrawInfo);
    procedure TopLeftMoved(const OldTopLeft: TGridCoord);
    procedure UpdateScrollPos;
    procedure UpdateScrollRange;
    function GetColWidths(Index: Longint): Integer;
    function GetRowHeights(Index: Longint): Integer;
    function GetSelection: TGridRect;
    function GetTabStops(Index: Longint): Boolean;
    function GetVisibleColCount: Integer;
    function GetVisibleRowCount: Integer;
    function IsActiveControl: Boolean;
    procedure ReadColWidths(Reader: TReader);
    procedure ReadRowHeights(Reader: TReader);
    procedure SetBorderStyle(Value: TBorderStyle);
    procedure SetCol(Value: Longint);
    procedure SetColCount(Value: Longint);
    procedure SetColWidths(Index: Longint; Value: Integer);
    procedure SetDefaultColWidth(Value: Integer);
    procedure SetDefaultRowHeight(Value: Integer);
    procedure SetEditorMode(Value: Boolean);
    procedure SetFixedColor(Value: TColor);
    procedure SetFixedCols(Value: Integer);
    procedure SetFixedRows(Value: Integer);
    procedure SetGridLineWidth(Value: Integer);
    procedure SetLeftCol(Value: Longint);
    procedure SetOptions(Value: TGridOptions);
    procedure SetRow(Value: Longint);
    procedure SetRowCount(Value: Longint);
    procedure SetRowHeights(Index: Longint; Value: Integer);
    procedure SetScrollBars(Value: TScrollStyle);
    procedure SetSelection(Value: TGridRect);
    procedure SetTabStops(Index: Longint; Value: Boolean);
    procedure SetTopRow(Value: Longint);
    procedure UpdateEdit;
    procedure UpdateText;
    procedure WriteColWidths(Writer: TWriter);
    procedure WriteRowHeights(Writer: TWriter);
    procedure CMCancelMode(var Msg: TMessage); message CM_CANCELMODE;
    procedure CMFontChanged(var Message: TMessage); message CM_FONTCHANGED;
    procedure CMCtl3DChanged(var Message: TMessage); message CM_CTL3DCHANGED;
    procedure CMDesignHitTest(var Msg: TCMDesignHitTest); message CM_DESIGNHITTEST;
    procedure CMWantSpecialKey(var Msg: TCMWantSpecialKey); message CM_WANTSPECIALKEY;
    procedure CMShowingChanged(var Message: TMessage); message CM_SHOWINGCHANGED;
    procedure WMChar(var Msg: TWMChar); message WM_CHAR;
    procedure WMCancelMode(var Msg: TWMCancelMode); message WM_CANCELMODE;
    procedure WMCommand(var Message: TWMCommand); message WM_COMMAND;
    procedure WMGetDlgCode(var Msg: TWMGetDlgCode); message WM_GETDLGCODE;
    procedure WMHScroll(var Msg: TWMHScroll); message WM_HSCROLL;
    procedure WMKillFocus(var Msg: TWMKillFocus); message WM_KILLFOCUS;
    procedure WMLButtonDown(var Message: TMessage); message WM_LBUTTONDOWN;
    procedure WMNCHitTest(var Msg: TWMNCHitTest); message WM_NCHITTEST;
    procedure WMSetCursor(var Msg: TWMSetCursor); message WM_SETCURSOR;
    procedure WMSetFocus(var Msg: TWMSetFocus); message WM_SETFOCUS;
    procedure WMSize(var Msg: TWMSize); message WM_SIZE;
    procedure WMTimer(var Msg: TWMTimer); message WM_TIMER;
    procedure WMVScroll(var Msg: TWMVScroll); message WM_VSCROLL;
  protected
    FGridState: TGridState;
    FSaveCellExtents: Boolean;
    DesignOptionsBoost: TGridOptions;
    VirtualView: Boolean;
    procedure CalcDrawInfo(var DrawInfo: TGridDrawInfo);
    procedure CalcFixedInfo(var DrawInfo: TGridDrawInfo);
    procedure CalcSizingState(X, Y: Integer; var State: TGridState;
      var Index: Longint; var SizingPos, SizingOfs: Integer;
      var FixedInfo: TGridDrawInfo); virtual;
    function CreateEditor: TInplaceEdit; virtual;
    procedure CreateParams(var Params: TCreateParams); override;
    procedure KeyDown(var Key: Word; Shift: TShiftState); override;
    procedure KeyPress(var Key: Char); override;
    procedure MouseDown(Button: TMouseButton; Shift: TShiftState;
      X, Y: Integer); override;
    procedure MouseMove(Shift: TShiftState; X, Y: Integer); override;
    procedure MouseUp(Button: TMouseButton; Shift: TShiftState;
      X, Y: Integer); override;
    procedure AdjustSize(Index, Amount: Longint; Rows: Boolean); reintroduce; dynamic;
    function BoxRect(ALeft, ATop, ARight, ABottom: Longint): TRect;
    procedure DoExit; override;
    function CellRect(ACol, ARow: Longint): TRect;
    function CanEditAcceptKey(Key: Char): Boolean; dynamic;
    function CanGridAcceptKey(Key: Word; Shift: TShiftState): Boolean; dynamic;
    function CanEditModify: Boolean; dynamic;
    function CanEditShow: Boolean; virtual;
    function DoMouseWheelDown(Shift: TShiftState; MousePos: TPoint): Boolean; override;
    function DoMouseWheelUp(Shift: TShiftState; MousePos: TPoint): Boolean; override;
    function GetEditText(ACol, ARow: Longint): string; dynamic;
    procedure SetEditText(ACol, ARow: Longint; const Value: string); dynamic;
    function GetEditMask(ACol, ARow: Longint): string; dynamic;
    function GetEditLimit: Integer; dynamic;
    function GetGridWidth: Integer;
    function GetGridHeight: Integer;
    procedure ShowEditorChar(Ch: Char);
    procedure InvalidateEditor;
    procedure MoveColumn(FromIndex, ToIndex: Longint);
    procedure ColumnMoved(FromIndex, ToIndex: Longint); dynamic;
    procedure MoveRow(FromIndex, ToIndex: Longint);
    procedure RowMoved(FromIndex, ToIndex: Longint); dynamic;
    procedure DrawCell(ACol, ARow: Longint; ARect: TRect;
      AState: TGridDrawState); virtual; abstract;
    procedure DefineProperties(Filer: TFiler); override;
    procedure MoveColRow(ACol, ARow: Longint; MoveAnchor, Show: Boolean);
    function SelectCell(ACol, ARow: Longint): Boolean; virtual;
    procedure SizeChanged(OldColCount, OldRowCount: Longint); dynamic;
    function Sizing(X, Y: Integer): Boolean;
    procedure ScrollData(DX, DY: Integer);
    procedure InvalidateCell(ACol, ARow: Longint);
    procedure InvalidateCol(ACol: Longint);
    procedure InvalidateRow(ARow: Longint);
    procedure TopLeftChanged; dynamic;
    procedure TimedScroll(Direction: TGridScrollDirection); dynamic;
    procedure Paint; override;
    procedure ColWidthsChanged; dynamic;
    procedure RowHeightsChanged; dynamic;
    procedure DeleteColumn(ACol: Longint); virtual;
    procedure DeleteRow(ARow: Longint); virtual;
    procedure UpdateDesigner;
    function BeginColumnDrag(var Origin, Destination: Integer;
      const MousePt: TPoint): Boolean; dynamic;
    function BeginRowDrag(var Origin, Destination: Integer;
      const MousePt: TPoint): Boolean; dynamic;
    function CheckColumnDrag(var Origin, Destination: Integer;
      const MousePt: TPoint): Boolean; dynamic;
    function CheckRowDrag(var Origin, Destination: Integer;
      const MousePt: TPoint): Boolean; dynamic;
    function EndColumnDrag(var Origin, Destination: Integer;
      const MousePt: TPoint): Boolean; dynamic;
    function EndRowDrag(var Origin, Destination: Integer;
      const MousePt: TPoint): Boolean; dynamic;
    property BorderStyle: TBorderStyle read FBorderStyle write SetBorderStyle default bsSingle;
    property Col: Longint read FCurrent.X write SetCol;
    property Color default clWindow;
    property ColCount: Longint read FColCount write SetColCount default 5;
    property ColWidths[Index: Longint]: Integer read GetColWidths write SetColWidths;
    property DefaultColWidth: Integer read FDefaultColWidth write SetDefaultColWidth default 64;
    property DefaultDrawing: Boolean read FDefaultDrawing write FDefaultDrawing default True;
    property DefaultRowHeight: Integer read FDefaultRowHeight write SetDefaultRowHeight default 24;
    property EditorMode: Boolean read FEditorMode write SetEditorMode;
    property FixedColor: TColor read FFixedColor write SetFixedColor default clBtnFace;
    property FixedCols: Integer read FFixedCols write SetFixedCols default 1;
    property FixedRows: Integer read FFixedRows write SetFixedRows default 1;
    property GridHeight: Integer read GetGridHeight;
    property GridLineWidth: Integer read FGridLineWidth write SetGridLineWidth default 1;
    property GridWidth: Integer read GetGridWidth;
    property HitTest: TPoint read FHitTest;
    property LeftCol: Longint read FTopLeft.X write SetLeftCol;
    property Options: TGridOptions read FOptions write SetOptions
      default [goFixedVertLine, goFixedHorzLine, goVertLine, goHorzLine,
      goRangeSelect];
    property ParentColor default False;
    property Row: Longint read FCurrent.Y write SetRow;
    property RowCount: Longint read FRowCount write SetRowCount default 5;
    property RowHeights[Index: Longint]: Integer read GetRowHeights write SetRowHeights;
    property ScrollBars: TScrollStyle read FScrollBars write SetScrollBars default ssBoth;
    property Selection: TGridRect read GetSelection write SetSelection;
    property TabStops[Index: Longint]: Boolean read GetTabStops write SetTabStops;
    property TopRow: Longint read FTopLeft.Y write SetTopRow;
    property VisibleColCount: Integer read GetVisibleColCount;
    property VisibleRowCount: Integer read GetVisibleRowCount;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    function MouseCoord(X, Y: Integer): TGridCoord;
    procedure HideEditor;
    procedure ShowEditor;
    property InplaceEditor: TInplaceEdit read FInplaceEdit;
  published
    property TabStop default True;
  end;

  { TDrawGrid }

  { A grid relies on the OnDrawCell event to display the cells.
     CellRect
       This method returns control relative screen coordinates of the cell or
       an empty rectangle if the cell is not visible.
     EditorMode
       Setting to true shows the editor, as if the F2 key was pressed, when
       goEditing is turned on and goAlwaysShowEditor is turned off.
     MouseToCell
       Takes control relative screen X, Y location and fills in the column and
       row that contain that point.
     OnColumnMoved
       Called when the user request to move a column with the mouse when
       the goColMoving option is on.
     OnDrawCell
       This event is passed the same information as the DrawCell method
       discussed above.
     OnGetEditMask
       Called to retrieve edit mask in the inplace editor when goEditing is
       turned on.
     OnGetEditText
       Called to retrieve text to edit when goEditing is turned on.
     OnRowMoved
       Called when the user request to move a row with the mouse when
       the goRowMoving option is on.
     OnSetEditText
       Called when goEditing is turned on to reflect changes to the text
       made by the editor.
     OnTopLeftChanged
       Invoked when TopRow or LeftCol change. }

  TGetEditEvent = procedure (Sender: TObject; ACol, ARow: Longint; var Value: string) of object;
  TSetEditEvent = procedure (Sender: TObject; ACol, ARow: Longint; const Value: string) of object;
  TMovedEvent = procedure (Sender: TObject; FromIndex, ToIndex: Longint) of object;

  TDrawGrid = class(TCustomGrid)
  private
    FOnColumnMoved: TMovedEvent;
    FOnDrawCell: TDrawCellEvent;
    FOnGetEditMask: TGetEditEvent;
    FOnGetEditText: TGetEditEvent;
    FOnRowMoved: TMovedEvent;
    FOnSelectCell: TSelectCellEvent;
    FOnSetEditText: TSetEditEvent;
    FOnTopLeftChanged: TNotifyEvent;
  protected
    procedure ColumnMoved(FromIndex, ToIndex: Longint); override;
    procedure DrawCell(ACol, ARow: Longint; ARect: TRect;
      AState: TGridDrawState); override;
    function GetEditMask(ACol, ARow: Longint): string; override;
    function GetEditText(ACol, ARow: Longint): string; override;
    procedure RowMoved(FromIndex, ToIndex: Longint); override;
    function SelectCell(ACol, ARow: Longint): Boolean; override;
    procedure SetEditText(ACol, ARow: Longint; const Value: string); override;
    procedure TopLeftChanged; override;
  public
    function CellRect(ACol, ARow: Longint): TRect;
    procedure MouseToCell(X, Y: Integer; var ACol, ARow: Longint);
    property Canvas;
    property Col;
    property ColWidths;
    property EditorMode;
    property GridHeight;
    property GridWidth;
    property LeftCol;
    property Selection;
    property Row;
    property RowHeights;
    property TabStops;
    property TopRow;
    property InplaceEditor; 
  published
    property Align;
    property Anchors;
    property BiDiMode;
    property BorderStyle;
    property Color;
    property ColCount;
    property Constraints;
    property Ctl3D;
    property DefaultColWidth;
    property DefaultRowHeight;
    property DefaultDrawing;
    property DragCursor;
    property DragKind;
    property DragMode;
    property Enabled;
    property FixedColor;
    property FixedCols;
    property RowCount;
    property FixedRows;
    property Font;
    property GridLineWidth;
    property Options;
    property ParentBiDiMode;
    property ParentColor;
    property ParentCtl3D;
    property ParentFont;
    property ParentShowHint;
    property PopupMenu;
    property ScrollBars;
    property ShowHint;
    property TabOrder;
    property TabStop;
    property Visible;
    property VisibleColCount;
    property VisibleRowCount;
    property OnClick;
    property OnColumnMoved: TMovedEvent read FOnColumnMoved write FOnColumnMoved;
    property OnContextPopup;
    property OnDblClick;
    property OnDragDrop;
    property OnDragOver;
    property OnDrawCell: TDrawCellEvent read FOnDrawCell write FOnDrawCell;
    property OnEndDock;
    property OnEndDrag;
    property OnEnter;
    property OnExit;
    property OnGetEditMask: TGetEditEvent read FOnGetEditMask write FOnGetEditMask;
    property OnGetEditText: TGetEditEvent read FOnGetEditText write FOnGetEditText;
    property OnKeyDown;
    property OnKeyPress;
    property OnKeyUp;
    property OnMouseDown;
    property OnMouseMove;
    property OnMouseUp;
    property OnMouseWheelDown;
    property OnMouseWheelUp;
    property OnRowMoved: TMovedEvent read FOnRowMoved write FOnRowMoved;
    property OnSelectCell: TSelectCellEvent read FOnSelectCell write FOnSelectCell;
    property OnSetEditText: TSetEditEvent read FOnSetEditText write FOnSetEditText;
    property OnStartDock;
    property OnStartDrag;
    property OnTopLeftChanged: TNotifyEvent read FOnTopLeftChanged write FOnTopLeftChanged;
  end;

  { TStringGrid }

  { TStringGrid adds to TDrawGrid the ability to save a string and associated
    object (much like TListBox).  It also adds to the DefaultDrawing the drawing
    of the string associated with the current cell.
      Cells
        A ColCount by RowCount array of strings which are associated with each
        cell.  By default, the string is drawn into the cell before OnDrawCell
        is called.  This can be turned off (along with all the other default
        drawing) by setting DefaultDrawing to false.
      Cols
        A TStrings object that contains the strings and objects in the column
        indicated by Index.  The TStrings will always have a count of RowCount.
        If a another TStrings is assigned to it, the strings and objects beyond
        RowCount are ignored.
      Objects
        A ColCount by Rowcount array of TObject's associated with each cell.
        Object put into this array will *not* be destroyed automatically when
        the grid is destroyed.
      Rows
        A TStrings object that contains the strings and objects in the row
        indicated by Index.  The TStrings will always have a count of ColCount.
        If a another TStrings is assigned to it, the strings and objects beyond
        ColCount are ignored. }

  TStringGrid = class;

  TStringGridStrings = class(TStrings)
  private
    FGrid: TStringGrid;
    FIndex: Integer;
    procedure CalcXY(Index: Integer; var X, Y: Integer);
  protected
    function Get(Index: Integer): string; override;
    function GetCount: Integer; override;
    function GetObject(Index: Integer): TObject; override;
    procedure Put(Index: Integer; const S: string); override;
    procedure PutObject(Index: Integer; AObject: TObject); override;
    procedure SetUpdateState(Updating: Boolean); override;
  public
    constructor Create(AGrid: TStringGrid; AIndex: Longint);
    function Add(const S: string): Integer; override;
    procedure Assign(Source: TPersistent); override;
    procedure Clear; override;
    procedure Delete(Index: Integer); override;
    procedure Insert(Index: Integer; const S: string); override;
  end;


  TStringGrid = class(TDrawGrid)
  private
    FData: Pointer;
    FRows: Pointer;
    FCols: Pointer;
    FUpdating: Boolean;
    FNeedsUpdating: Boolean;
    FEditUpdate: Integer;
    procedure DisableEditUpdate;
    procedure EnableEditUpdate;
    procedure Initialize;
    procedure Update(ACol, ARow: Integer); reintroduce;
    function GetCells(ACol, ARow: Integer): string;
    function GetCols(Index: Integer): TStrings;
    function GetObjects(ACol, ARow: Integer): TObject;
    function GetRows(Index: Integer): TStrings;
    procedure SetCells(ACol, ARow: Integer; const Value: string);
    procedure SetCols(Index: Integer; Value: TStrings);
    procedure SetObjects(ACol, ARow: Integer; Value: TObject);
    procedure SetRows(Index: Integer; Value: TStrings);
    function EnsureColRow(Index: Integer; IsCol: Boolean): TStringGridStrings;
    function EnsureDataRow(ARow: Integer): Pointer;
  protected
    procedure ColumnMoved(FromIndex, ToIndex: Longint); override;
    procedure DrawCell(ACol, ARow: Longint; ARect: TRect;
      AState: TGridDrawState); override;
    function GetEditText(ACol, ARow: Longint): string; override;
    procedure SetEditText(ACol, ARow: Longint; const Value: string); override;
    procedure RowMoved(FromIndex, ToIndex: Longint); override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure SetUpdateState(Updating: Boolean);
    property Cells[ACol, ARow: Integer]: string read GetCells write SetCells;
    property Cols[Index: Integer]: TStrings read GetCols write SetCols;
    property Objects[ACol, ARow: Integer]: TObject read GetObjects write SetObjects;
    property Rows[Index: Integer]: TStrings read GetRows write SetRows;
  end;

implementation

uses Math, Consts, RTLConsts;

type
  PIntArray = ^TIntArray;
  TIntArray = array[0..MaxCustomExtents] of Integer;

procedure InvalidOp(const id: string);
begin
  raise EInvalidGridOperation.Create(id);
end;

function GridRect(Coord1, Coord2: TGridCoord): TGridRect;
begin
  with Result do
  begin
    Left := Coord2.X;
    if Coord1.X < Coord2.X then Left := Coord1.X;
    Right := Coord1.X;
    if Coord1.X < Coord2.X then Right := Coord2.X;
    Top := Coord2.Y;
    if Coord1.Y < Coord2.Y then Top := Coord1.Y;
    Bottom := Coord1.Y;
    if Coord1.Y < Coord2.Y then Bottom := Coord2.Y;
  end;
end;

function PointInGridRect(Col, Row: Longint; const Rect: TGridRect): Boolean;
begin
  Result := (Col >= Rect.Left) and (Col <= Rect.Right) and (Row >= Rect.Top)
    and (Row <= Rect.Bottom);
end;

type
  TXorRects = array[0..3] of TRect;

procedure XorRects(const R1, R2: TRect; var XorRects: TXorRects);
var
  Intersect, Union: TRect;

  function PtInRect(X, Y: Integer; const Rect: TRect): Boolean;
  begin
    with Rect do Result := (X >= Left) and (X <= Right) and (Y >= Top) and
      (Y <= Bottom);
  end;

  function Includes(const P1: TPoint; var P2: TPoint): Boolean;
  begin
    with P1 do
    begin
      Result := PtInRect(X, Y, R1) or PtInRect(X, Y, R2);
      if Result then P2 := P1;
    end;
  end;

  function Build(var R: TRect; const P1, P2, P3: TPoint): Boolean;
  begin
    Build := True;
    with R do
      if Includes(P1, TopLeft) then
      begin
        if not Includes(P3, BottomRight) then BottomRight := P2;
      end
      else if Includes(P2, TopLeft) then BottomRight := P3
      else Build := False;
  end;

begin
  FillChar(XorRects, SizeOf(XorRects), 0);
  if not Bool(IntersectRect(Intersect, R1, R2)) then
  begin
    { Don't intersect so its simple }
    XorRects[0] := R1;
    XorRects[1] := R2;
  end
  else
  begin
    UnionRect(Union, R1, R2);
    if Build(XorRects[0],
      Point(Union.Left, Union.Top),
      Point(Union.Left, Intersect.Top),
      Point(Union.Left, Intersect.Bottom)) then
      XorRects[0].Right := Intersect.Left;
    if Build(XorRects[1],
      Point(Intersect.Left, Union.Top),
      Point(Intersect.Right, Union.Top),
      Point(Union.Right, Union.Top)) then
      XorRects[1].Bottom := Intersect.Top;
    if Build(XorRects[2],
      Point(Union.Right, Intersect.Top),
      Point(Union.Right, Intersect.Bottom),
      Point(Union.Right, Union.Bottom)) then
      XorRects[2].Left := Intersect.Right;
    if Build(XorRects[3],
      Point(Union.Left, Union.Bottom),
      Point(Intersect.Left, Union.Bottom),
      Point(Intersect.Right, Union.Bottom)) then
      XorRects[3].Top := Intersect.Bottom;
  end;
end;

procedure ModifyExtents(var Extents: Pointer; Index, Amount: Longint;
  Default: Integer);
var
  LongSize, OldSize: LongInt;
  NewSize: Integer;
  I: Integer;
begin
  if Amount <> 0 then
  begin
    if not Assigned(Extents) then OldSize := 0
    else OldSize := PIntArray(Extents)^[0];
    if (Index < 0) or (OldSize < Index) then InvalidOp(SIndexOutOfRange);
    LongSize := OldSize + Amount;
    if LongSize < 0 then InvalidOp(STooManyDeleted)
    else if LongSize >= MaxListSize - 1 then InvalidOp(SGridTooLarge);
    NewSize := Cardinal(LongSize);
    if NewSize > 0 then Inc(NewSize);
    ReallocMem(Extents, NewSize * SizeOf(Integer));
    if Assigned(Extents) then
    begin
      I := Index + 1;
      while I < NewSize do
      begin
        PIntArray(Extents)^[I] := Default;
        Inc(I);
      end;
      PIntArray(Extents)^[0] := NewSize-1;
    end;
  end;
end;

procedure UpdateExtents(var Extents: Pointer; NewSize: Longint;
  Default: Integer);
var
  OldSize: Integer;
begin
  OldSize := 0;
  if Assigned(Extents) then OldSize := PIntArray(Extents)^[0];
  ModifyExtents(Extents, OldSize, NewSize - OldSize, Default);
end;

procedure MoveExtent(var Extents: Pointer; FromIndex, ToIndex: Longint);
var
  Extent: Integer;
begin
  if Assigned(Extents) then
  begin
    Extent := PIntArray(Extents)^[FromIndex];
    if FromIndex < ToIndex then
      Move(PIntArray(Extents)^[FromIndex + 1], PIntArray(Extents)^[FromIndex],
        (ToIndex - FromIndex) * SizeOf(Integer))
    else if FromIndex > ToIndex then
      Move(PIntArray(Extents)^[ToIndex], PIntArray(Extents)^[ToIndex + 1],
        (FromIndex - ToIndex) * SizeOf(Integer));
    PIntArray(Extents)^[ToIndex] := Extent;
  end;
end;

function CompareExtents(E1, E2: Pointer): Boolean;
var
  I: Integer;
begin
  Result := False;
  if E1 <> nil then
  begin
    if E2 <> nil then
    begin
      for I := 0 to PIntArray(E1)^[0] do
        if PIntArray(E1)^[I] <> PIntArray(E2)^[I] then Exit;
      Result := True;
    end
  end
  else Result := E2 = nil;
end;

{ Private. LongMulDiv multiplys the first two arguments and then
  divides by the third.  This is used so that real number
  (floating point) arithmetic is not necessary.  This routine saves
  the possible 64-bit value in a temp before doing the divide.  Does
  not do error checking like divide by zero.  Also assumes that the
  result is in the 32-bit range (Actually 31-bit, since this algorithm
  is for unsigned). }

function LongMulDiv(Mult1, Mult2, Div1: Longint): Longint; stdcall;
  external 'kernel32.dll' name 'MulDiv';

type
  TSelection = record
    StartPos, EndPos: Integer;
  end;

constructor TInplaceEdit.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  ParentCtl3D := False;
  Ctl3D := False;
  TabStop := False;
  BorderStyle := bsNone;
  DoubleBuffered := False;
end;

procedure TInplaceEdit.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  Params.Style := Params.Style or ES_MULTILINE;
end;

procedure TInplaceEdit.SetGrid(Value: TCustomGrid);
begin
  FGrid := Value;
end;

procedure TInplaceEdit.CMShowingChanged(var Message: TMessage);
begin
  { Ignore showing using the Visible property }
end;

procedure TInplaceEdit.WMGetDlgCode(var Message: TWMGetDlgCode);
begin
  inherited;
  if goTabs in Grid.Options then
    Message.Result := Message.Result or DLGC_WANTTAB;
end;

procedure TInplaceEdit.WMPaste(var Message);
begin
  if not EditCanModify then Exit;
  inherited
end;

procedure TInplaceEdit.WMClear(var Message);
begin
  if not EditCanModify then Exit;
  inherited;
end;

procedure TInplaceEdit.WMCut(var Message);
begin
  if not EditCanModify then Exit;
  inherited;
end;

procedure TInplaceEdit.DblClick;
begin
  Grid.DblClick;
end;

function TInplaceEdit.DoMouseWheel(Shift: TShiftState; WheelDelta: Integer;
  MousePos: TPoint): Boolean;
begin
  Result := Grid.DoMouseWheel(Shift, WheelDelta, MousePos);
end;

function TInplaceEdit.EditCanModify: Boolean;
begin
  Result := Grid.CanEditModify;
end;

procedure TInplaceEdit.KeyDown(var Key: Word; Shift: TShiftState);

  procedure SendToParent;
  begin
    Grid.KeyDown(Key, Shift);
    Key := 0;
  end;

  procedure ParentEvent;
  var
    GridKeyDown: TKeyEvent;
  begin
    GridKeyDown := Grid.OnKeyDown;
    if Assigned(GridKeyDown) then GridKeyDown(Grid, Key, Shift);
  end;

  function ForwardMovement: Boolean;
  begin
    Result := goAlwaysShowEditor in Grid.Options;
  end;

  function Ctrl: Boolean;
  begin
    Result := ssCtrl in Shift;
  end;

  function Selection: TSelection;
  begin
    SendMessage(Handle, EM_GETSEL, Longint(@Result.StartPos), Longint(@Result.EndPos));
  end;

  function RightSide: Boolean;
  begin
    with Selection do
      Result := ((StartPos = 0) or (EndPos = StartPos)) and
        (EndPos = GetTextLen);
   end;

  function LeftSide: Boolean;
  begin
    with Selection do
      Result := (StartPos = 0) and ((EndPos = 0) or (EndPos = GetTextLen));
  end;

begin
  case Key of
    VK_UP, VK_DOWN, VK_PRIOR, VK_NEXT, VK_ESCAPE: SendToParent;
    VK_INSERT:
      if Shift = [] then SendToParent
      else if (Shift = [ssShift]) and not Grid.CanEditModify then Key := 0;
    VK_LEFT: if ForwardMovement and (Ctrl or LeftSide) then SendToParent;
    VK_RIGHT: if ForwardMovement and (Ctrl or RightSide) then SendToParent;
    VK_HOME: if ForwardMovement and (Ctrl or LeftSide) then SendToParent;
    VK_END: if ForwardMovement and (Ctrl or RightSide) then SendToParent;
    VK_F2:
      begin
        ParentEvent;
        if Key = VK_F2 then
        begin
          Deselect;
          Exit;
        end;
      end;
    VK_TAB: if not (ssAlt in Shift) then SendToParent;
  end;
  if (Key = VK_DELETE) and not Grid.CanEditModify then Key := 0;
  if Key <> 0 then
  begin
    ParentEvent;
    inherited KeyDown(Key, Shift);
  end;
end;

procedure TInplaceEdit.KeyPress(var Key: Char);
var
  Selection: TSelection;
begin
  Grid.KeyPress(Key);
  if (Key in [#32..#255]) and not Grid.CanEditAcceptKey(Key) then
  begin
    Key := #0;
    MessageBeep(0);
  end;
  case Key of
    #9, #27: Key := #0;
    #13:
      begin
        SendMessage(Handle, EM_GETSEL, Longint(@Selection.StartPos), Longint(@Selection.EndPos));
        if (Selection.StartPos = 0) and (Selection.EndPos = GetTextLen) then
          Deselect else
          SelectAll;
        Key := #0;
      end;
    ^H, ^V, ^X, #32..#255:
      if not Grid.CanEditModify then Key := #0;
  end;
  if Key <> #0 then inherited KeyPress(Key);
end;

procedure TInplaceEdit.KeyUp(var Key: Word; Shift: TShiftState);
begin
  Grid.KeyUp(Key, Shift);
end;

procedure TInplaceEdit.WndProc(var Message: TMessage);
begin
  case Message.Msg of
    WM_SETFOCUS:
      begin
        if (GetParentForm(Self) = nil) or GetParentForm(Self).SetFocusedControl(Grid) then Dispatch(Message);
        Exit;
      end;
    WM_LBUTTONDOWN:
      begin
        if UINT(GetMessageTime - FClickTime) < GetDoubleClickTime then
          Message.Msg := WM_LBUTTONDBLCLK;
        FClickTime := 0;
      end;
  end;
  inherited WndProc(Message);
end;

procedure TInplaceEdit.Deselect;
begin
  SendMessage(Handle, EM_SETSEL, $7FFFFFFF, Longint($FFFFFFFF));
end;

procedure TInplaceEdit.Invalidate;
var
  Cur: TRect;
begin
  ValidateRect(Handle, nil);
  InvalidateRect(Handle, nil, True);
  Windows.GetClientRect(Handle, Cur);
  MapWindowPoints(Handle, Grid.Handle, Cur, 2);
  ValidateRect(Grid.Handle, @Cur);
  InvalidateRect(Grid.Handle, @Cur, False);
end;

procedure TInplaceEdit.Hide;
begin
  if HandleAllocated and IsWindowVisible(Handle) then
  begin
    Invalidate;
    SetWindowPos(Handle, 0, 0, 0, 0, 0, SWP_HIDEWINDOW or SWP_NOZORDER or
      SWP_NOREDRAW);
    if Focused then Windows.SetFocus(Grid.Handle);
  end;
end;

function TInplaceEdit.PosEqual(const Rect: TRect): Boolean;
var
  Cur: TRect;
begin
  GetWindowRect(Handle, Cur);
  MapWindowPoints(HWND_DESKTOP, Grid.Handle, Cur, 2);
  Result := EqualRect(Rect, Cur);
end;

procedure TInplaceEdit.InternalMove(const Loc: TRect; Redraw: Boolean);
begin
  if IsRectEmpty(Loc) then Hide
  else
  begin
    CreateHandle;
    Redraw := Redraw or not IsWindowVisible(Handle);
    Invalidate;
    with Loc do
      SetWindowPos(Handle, HWND_TOP, Left, Top, Right - Left, Bottom - Top,
        SWP_SHOWWINDOW or SWP_NOREDRAW);
    BoundsChanged;
    if Redraw then Invalidate;
    if Grid.Focused then
      Windows.SetFocus(Handle);
  end;
end;

procedure TInplaceEdit.BoundsChanged;
var
  R: TRect;
begin
  R := Rect(2, 2, Width - 2, Height);
  SendMessage(Handle, EM_SETRECTNP, 0, LongInt(@R));
  SendMessage(Handle, EM_SCROLLCARET, 0, 0);
end;

procedure TInplaceEdit.UpdateLoc(const Loc: TRect);
begin
  InternalMove(Loc, False);
end;

function TInplaceEdit.Visible: Boolean;
begin
  Result := IsWindowVisible(Handle);
end;

procedure TInplaceEdit.Move(const Loc: TRect);
begin
  InternalMove(Loc, True);
end;

procedure TInplaceEdit.SetFocus;
begin
  if IsWindowVisible(Handle) then
    Windows.SetFocus(Handle);
end;

procedure TInplaceEdit.UpdateContents;
begin
  Text := '';
  EditMask := Grid.GetEditMask(Grid.Col, Grid.Row);
  Text := Grid.GetEditText(Grid.Col, Grid.Row);
  MaxLength := Grid.GetEditLimit;
end;

{ TCustomGrid }

constructor TCustomGrid.Create(AOwner: TComponent);
const
  GridStyle = [csCaptureMouse, csOpaque, csDoubleClicks];
begin
  inherited Create(AOwner);
  if NewStyleControls then
    ControlStyle := GridStyle else
    ControlStyle := GridStyle + [csFramed];
  FCanEditModify := True;
  FColCount := 5;
  FRowCount := 5;
  FFixedCols := 1;
  FFixedRows := 1;
  FGridLineWidth := 1;
  FOptions := [goFixedVertLine, goFixedHorzLine, goVertLine, goHorzLine,
    goRangeSelect];
  DesignOptionsBoost := [goColSizing, goRowSizing];
  FFixedColor := clBtnFace;
  FScrollBars := ssBoth;
  FBorderStyle := bsSingle;
  FDefaultColWidth := 64;
  FDefaultRowHeight := 24;
  FDefaultDrawing := True;
  FSaveCellExtents := True;
  FEditorMode := False;
  Color := clWindow;
  ParentColor := False;
  TabStop := True;
  SetBounds(Left, Top, FColCount * FDefaultColWidth,
    FRowCount * FDefaultRowHeight);
  FInplaceEdit := CreateEditor;
  FInplaceEdit.SetGrid(Self);
  FInplaceEdit.Parent := Self;
  Initialize;
end;

destructor TCustomGrid.Destroy;
begin
  FInplaceEdit.Free;
  inherited Destroy;
  FreeMem(FColWidths);
  FreeMem(FRowHeights);
  FreeMem(FTabStops);
end;

procedure TCustomGrid.AdjustSize(Index, Amount: Longint; Rows: Boolean);
var
  NewCur: TGridCoord;
  OldRows, OldCols: Longint;
  MovementX, MovementY: Longint;
  MoveRect: TGridRect;
  ScrollArea: TRect;
  AbsAmount: Longint;

  function DoSizeAdjust(var Count: Longint; var Extents: Pointer;
    DefaultExtent: Integer; var Current: Longint): Longint;
  var
    I: Integer;
    NewCount: Longint;
  begin
    NewCount := Count + Amount;
    if NewCount < Index then InvalidOp(STooManyDeleted);
    if (Amount < 0) and Assigned(Extents) then
    begin
      Result := 0;
      for I := Index to Index - Amount - 1 do
        Inc(Result, PIntArray(Extents)^[I]);
    end
    else
      Result := Amount * DefaultExtent;
    if Extents <> nil then
      ModifyExtents(Extents, Index, Amount, DefaultExtent);
    Count := NewCount;
    if Current >= Index then
      if (Amount < 0) and (Current < Index - Amount) then Current := Index
      else Inc(Current, Amount);
  end;

begin
  if Amount = 0 then Exit;
  NewCur := FCurrent;
  OldCols := ColCount;
  OldRows := RowCount;
  MoveRect.Left := FixedCols;
  MoveRect.Right := ColCount - 1;
  MoveRect.Top := FixedRows;
  MoveRect.Bottom := RowCount - 1;
  MovementX := 0;
  MovementY := 0;
  AbsAmount := Amount;
  if AbsAmount < 0 then AbsAmount := -AbsAmount;
  if Rows then
  begin
    MovementY := DoSizeAdjust(FRowCount, FRowHeights, DefaultRowHeight, NewCur.Y);
    MoveRect.Top := Index;
    if Index + AbsAmount <= TopRow then MoveRect.Bottom := TopRow - 1;
  end
  else
  begin
    MovementX := DoSizeAdjust(FColCount, FColWidths, DefaultColWidth, NewCur.X);
    MoveRect.Left := Index;
    if Index + AbsAmount <= LeftCol then MoveRect.Right := LeftCol - 1;
  end;
  GridRectToScreenRect(MoveRect, ScrollArea, True);
  if not IsRectEmpty(ScrollArea) then
  begin
    ScrollWindow(Handle, MovementX, MovementY, @ScrollArea, @ScrollArea);
    UpdateWindow(Handle);
  end;
  SizeChanged(OldCols, OldRows);
  if (NewCur.X <> FCurrent.X) or (NewCur.Y <> FCurrent.Y) then
    MoveCurrent(NewCur.X, NewCur.Y, True, True);
end;

function TCustomGrid.BoxRect(ALeft, ATop, ARight, ABottom: Longint): TRect;
var
  GridRect: TGridRect;
begin
  GridRect.Left := ALeft;
  GridRect.Right := ARight;
  GridRect.Top := ATop;
  GridRect.Bottom := ABottom;
  GridRectToScreenRect(GridRect, Result, False);
end;

procedure TCustomGrid.DoExit;
begin
  inherited DoExit;
  if not (goAlwaysShowEditor in Options) then HideEditor;
end;

function TCustomGrid.CellRect(ACol, ARow: Longint): TRect;
begin
  Result := BoxRect(ACol, ARow, ACol, ARow);
end;

function TCustomGrid.CanEditAcceptKey(Key: Char): Boolean;
begin
  Result := True;
end;

function TCustomGrid.CanGridAcceptKey(Key: Word; Shift: TShiftState): Boolean;
begin
  Result := True;
end;

function TCustomGrid.CanEditModify: Boolean;
begin
  Result := FCanEditModify;
end;

function TCustomGrid.CanEditShow: Boolean;
begin
  Result := ([goRowSelect, goEditing] * Options = [goEditing]) and
    FEditorMode and not (csDesigning in ComponentState) and HandleAllocated and
    ((goAlwaysShowEditor in Options) or IsActiveControl);
end;

function TCustomGrid.IsActiveControl: Boolean;
var
  H: Hwnd;
  ParentForm: TCustomForm;
begin
  Result := False;
  ParentForm := GetParentForm(Self);
  if Assigned(ParentForm) then
  begin
    if (ParentForm.ActiveControl = Self) then
      Result := True
  end
  else
  begin
    H := GetFocus;
    while IsWindow(H) and (Result = False) do
    begin
      if H = WindowHandle then
        Result := True
      else
        H := GetParent(H);
    end;
  end;
end;

function TCustomGrid.GetEditMask(ACol, ARow: Longint): string;
begin
  Result := '';
end;

function TCustomGrid.GetEditText(ACol, ARow: Longint): string;
begin
  Result := '';
end;

procedure TCustomGrid.SetEditText(ACol, ARow: Longint; const Value: string);
begin
end;

function TCustomGrid.GetEditLimit: Integer;
begin
  Result := 0;
end;

procedure TCustomGrid.HideEditor;
begin
  FEditorMode := False;
  HideEdit;
end;

procedure TCustomGrid.ShowEditor;
begin
  FEditorMode := True;
  UpdateEdit;
end;

procedure TCustomGrid.ShowEditorChar(Ch: Char);
begin
  ShowEditor;
  if FInplaceEdit <> nil then
    PostMessage(FInplaceEdit.Handle, WM_CHAR, Word(Ch), 0);
end;

procedure TCustomGrid.InvalidateEditor;
begin
  FInplaceCol := -1;
  FInplaceRow := -1;
  UpdateEdit;
end;

procedure TCustomGrid.ReadColWidths(Reader: TReader);
var
  I: Integer;
begin
  with Reader do
  begin
    ReadListBegin;
    for I := 0 to ColCount - 1 do ColWidths[I] := ReadInteger;
    ReadListEnd;
  end;
end;

procedure TCustomGrid.ReadRowHeights(Reader: TReader);
var
  I: Integer;
begin
  with Reader do
  begin
    ReadListBegin;
    for I := 0 to RowCount - 1 do RowHeights[I] := ReadInteger;
    ReadListEnd;
  end;
end;

procedure TCustomGrid.WriteColWidths(Writer: TWriter);
var
  I: Integer;
begin
  with Writer do
  begin
    WriteListBegin;
    for I := 0 to ColCount - 1 do WriteInteger(ColWidths[I]);
    WriteListEnd;
  end;
end;

procedure TCustomGrid.WriteRowHeights(Writer: TWriter);
var
  I: Integer;
begin
  with Writer do
  begin
    WriteListBegin;
    for I := 0 to RowCount - 1 do WriteInteger(RowHeights[I]);
    WriteListEnd;
  end;
end;

procedure TCustomGrid.DefineProperties(Filer: TFiler);

  function DoColWidths: Boolean;
  begin
    if Filer.Ancestor <> nil then
      Result := not CompareExtents(TCustomGrid(Filer.Ancestor).FColWidths, FColWidths)
    else
      Result := FColWidths <> nil;
  end;

  function DoRowHeights: Boolean;
  begin
    if Filer.Ancestor <> nil then
      Result := not CompareExtents(TCustomGrid(Filer.Ancestor).FRowHeights, FRowHeights)
    else
      Result := FRowHeights <> nil;
  end;


begin
  inherited DefineProperties(Filer);
  if FSaveCellExtents then
    with Filer do
    begin
      DefineProperty('ColWidths', ReadColWidths, WriteColWidths, DoColWidths);
      DefineProperty('RowHeights', ReadRowHeights, WriteRowHeights, DoRowHeights);
    end;
end;

procedure TCustomGrid.MoveColumn(FromIndex, ToIndex: Longint);
var
  Rect: TGridRect;
begin
  if FromIndex = ToIndex then Exit;
  if Assigned(FColWidths) then
  begin
    MoveExtent(FColWidths, FromIndex + 1, ToIndex + 1);
    MoveExtent(FTabStops, FromIndex + 1, ToIndex + 1);
  end;
  MoveAdjust(FCurrent.X, FromIndex, ToIndex);
  MoveAdjust(FAnchor.X, FromIndex, ToIndex);
  MoveAdjust(FInplaceCol, FromIndex, ToIndex);
  Rect.Top := 0;
  Rect.Bottom := VisibleRowCount;
  if FromIndex < ToIndex then
  begin
    Rect.Left := FromIndex;
    Rect.Right := ToIndex;
  end
  else
  begin
    Rect.Left := ToIndex;
    Rect.Right := FromIndex;
  end;
  InvalidateRect(Rect);
  ColumnMoved(FromIndex, ToIndex);
  if Assigned(FColWidths) then
    ColWidthsChanged;
  UpdateEdit;
end;

procedure TCustomGrid.ColumnMoved(FromIndex, ToIndex: Longint);
begin
end;

procedure TCustomGrid.MoveRow(FromIndex, ToIndex: Longint);
begin
  if Assigned(FRowHeights) then
    MoveExtent(FRowHeights, FromIndex + 1, ToIndex + 1);
  MoveAdjust(FCurrent.Y, FromIndex, ToIndex);
  MoveAdjust(FAnchor.Y, FromIndex, ToIndex);
  MoveAdjust(FInplaceRow, FromIndex, ToIndex);
  RowMoved(FromIndex, ToIndex);
  if Assigned(FRowHeights) then
    RowHeightsChanged;
  UpdateEdit;
end;

procedure TCustomGrid.RowMoved(FromIndex, ToIndex: Longint);
begin
end;

function TCustomGrid.MouseCoord(X, Y: Integer): TGridCoord;
var
  DrawInfo: TGridDrawInfo;
begin
  CalcDrawInfo(DrawInfo);
  Result := CalcCoordFromPoint(X, Y, DrawInfo);
  if Result.X < 0 then Result.Y := -1
  else if Result.Y < 0 then Result.X := -1;
end;

procedure TCustomGrid.MoveColRow(ACol, ARow: Longint; MoveAnchor,
  Show: Boolean);
begin
  MoveCurrent(ACol, ARow, MoveAnchor, Show);
end;

function TCustomGrid.SelectCell(ACol, ARow: Longint): Boolean;
begin
  Result := True;
end;

procedure TCustomGrid.SizeChanged(OldColCount, OldRowCount: Longint);
begin
end;

function TCustomGrid.Sizing(X, Y: Integer): Boolean;
var
  DrawInfo: TGridDrawInfo;
  State: TGridState;
  Index: Longint;
  Pos, Ofs: Integer;
begin
  State := FGridState;
  if State = gsNormal then
  begin
    CalcDrawInfo(DrawInfo);
    CalcSizingState(X, Y, State, Index, Pos, Ofs, DrawInfo);
  end;
  Result := State <> gsNormal;
end;

procedure TCustomGrid.TopLeftChanged;
begin
  if FEditorMode and (FInplaceEdit <> nil) then FInplaceEdit.UpdateLoc(CellRect(Col, Row));
end;

procedure FillDWord(var Dest; Count, Value: Integer); register;
asm
  XCHG  EDX, ECX
  PUSH  EDI
  MOV   EDI, EAX
  MOV   EAX, EDX
  REP   STOSD
  POP   EDI
end;

{ StackAlloc allocates a 'small' block of memory from the stack by
  decrementing SP.  This provides the allocation speed of a local variable,
  but the runtime size flexibility of heap allocated memory.  }
function StackAlloc(Size: Integer): Pointer; register;
asm
  POP   ECX          { return address }
  MOV   EDX, ESP
  ADD   EAX, 3
  AND   EAX, not 3   // round up to keep ESP dword aligned
  CMP   EAX, 4092
  JLE   @@2
@@1:
  SUB   ESP, 4092
  PUSH  EAX          { make sure we touch guard page, to grow stack }
  SUB   EAX, 4096
  JNS   @@1
  ADD   EAX, 4096
@@2:
  SUB   ESP, EAX
  MOV   EAX, ESP     { function result = low memory address of block }
  PUSH  EDX          { save original SP, for cleanup }
  MOV   EDX, ESP
  SUB   EDX, 4
  PUSH  EDX          { save current SP, for sanity check  (sp = [sp]) }
  PUSH  ECX          { return to caller }
end;

{ StackFree pops the memory allocated by StackAlloc off the stack.
- Calling StackFree is optional - SP will be restored when the calling routine
  exits, but it's a good idea to free the stack allocated memory ASAP anyway.
- StackFree must be called in the same stack context as StackAlloc - not in
  a subroutine or finally block.
- Multiple StackFree calls must occur in reverse order of their corresponding
  StackAlloc calls.
- Built-in sanity checks guarantee that an improper call to StackFree will not
  corrupt the stack. Worst case is that the stack block is not released until
  the calling routine exits. }
procedure StackFree(P: Pointer); register;
asm
  POP   ECX                     { return address }
  MOV   EDX, DWORD PTR [ESP]
  SUB   EAX, 8
  CMP   EDX, ESP                { sanity check #1 (SP = [SP]) }
  JNE   @@1
  CMP   EDX, EAX                { sanity check #2 (P = this stack block) }
  JNE   @@1
  MOV   ESP, DWORD PTR [ESP+4]  { restore previous SP  }
@@1:
  PUSH  ECX                     { return to caller }
end;

procedure TCustomGrid.Paint;
var
  LineColor: TColor;
  DrawInfo: TGridDrawInfo;
  Sel: TGridRect;
  UpdateRect: TRect;
  AFocRect, FocRect: TRect;
  PointsList: PIntArray;
  StrokeList: PIntArray;
  MaxStroke: Integer;
  FrameFlags1, FrameFlags2: DWORD;

  procedure DrawLines(DoHorz, DoVert: Boolean; Col, Row: Longint;
    const CellBounds: array of Integer; OnColor, OffColor: TColor);

  { Cellbounds is 4 integers: StartX, StartY, StopX, StopY
    Horizontal lines:  MajorIndex = 0
    Vertical lines:    MajorIndex = 1 }

  const
    FlatPenStyle = PS_Geometric or PS_Solid or PS_EndCap_Flat or PS_Join_Miter;

    procedure DrawAxisLines(const AxisInfo: TGridAxisDrawInfo;
      Cell, MajorIndex: Integer; UseOnColor: Boolean);
    var
      Line: Integer;
      LogBrush: TLOGBRUSH;
      Index: Integer;
      Points: PIntArray;
      StopMajor, StartMinor, StopMinor: Integer;
    begin
      with Canvas, AxisInfo do
      begin
        if EffectiveLineWidth <> 0 then
        begin
          Pen.Width := GridLineWidth;
          if UseOnColor then
            Pen.Color := OnColor
          else
            Pen.Color := OffColor;
          if Pen.Width > 1 then
          begin
            LogBrush.lbStyle := BS_Solid;
            LogBrush.lbColor := Pen.Color;
            LogBrush.lbHatch := 0;
            Pen.Handle := ExtCreatePen(FlatPenStyle, Pen.Width, LogBrush, 0, nil);
          end;
          Points := PointsList;
          Line := CellBounds[MajorIndex] + EffectiveLineWidth shr 1 +
            GetExtent(Cell);
          //!!! ??? Line needs to be incremented for RightToLeftAlignment ???
          if UseRightToLeftAlignment and (MajorIndex = 0) then Inc(Line);
          StartMinor := CellBounds[MajorIndex xor 1];
          StopMinor := CellBounds[2 + (MajorIndex xor 1)];
          StopMajor := CellBounds[2 + MajorIndex] + EffectiveLineWidth;
          Index := 0;
          repeat
            Points^[Index + MajorIndex] := Line;         { MoveTo }
            Points^[Index + (MajorIndex xor 1)] := StartMinor;
            Inc(Index, 2);
            Points^[Index + MajorIndex] := Line;         { LineTo }
            Points^[Index + (MajorIndex xor 1)] := StopMinor;
            Inc(Index, 2);
            Inc(Cell);
            // For hidden columns/rows, set extent to -EffectiveLineWidth
            Inc(Line, GetExtent(Cell) + EffectiveLineWidth);
          until (Line > StopMajor) or (Cell > LastFullVisibleCell);
           { 2 integers per point, 2 points per line -> Index div 4 }
          PolyPolyLine(Canvas.Handle, Points^, StrokeList^, Index shr 2);
        end;
      end;
    end;

  begin
    if (CellBounds[0] = CellBounds[2]) or (CellBounds[1] = CellBounds[3]) then Exit;
    if not DoHorz then
    begin
      DrawAxisLines(DrawInfo.Vert, Row, 1, DoHorz);
      DrawAxisLines(DrawInfo.Horz, Col, 0, DoVert);
    end
    else
    begin
      DrawAxisLines(DrawInfo.Horz, Col, 0, DoVert);
      DrawAxisLines(DrawInfo.Vert, Row, 1, DoHorz);
    end;
  end;

  procedure DrawCells(ACol, ARow: Longint; StartX, StartY, StopX, StopY: Integer;
    Color: TColor; IncludeDrawState: TGridDrawState);
  var
    CurCol, CurRow: Longint;
    AWhere, Where, TempRect: TRect;
    DrawState: TGridDrawState;
    Focused: Boolean;
  begin
    CurRow := ARow;
    Where.Top := StartY;
    while (Where.Top < StopY) and (CurRow < RowCount) do
    begin
      CurCol := ACol;
      Where.Left := StartX;
      Where.Bottom := Where.Top + RowHeights[CurRow];
      while (Where.Left < StopX) and (CurCol < ColCount) do
      begin
        Where.Right := Where.Left + ColWidths[CurCol];
        if (Where.Right > Where.Left) and RectVisible(Canvas.Handle, Where) then
        begin
          DrawState := IncludeDrawState;
          Focused := IsActiveControl;
          if Focused and (CurRow = Row) and (CurCol = Col)  then
            Include(DrawState, gdFocused);
          if PointInGridRect(CurCol, CurRow, Sel) then
            Include(DrawState, gdSelected);
          if not (gdFocused in DrawState) or not (goEditing in Options) or
            not FEditorMode or (csDesigning in ComponentState) then
          begin
            if DefaultDrawing or (csDesigning in ComponentState) then
              with Canvas do
              begin
                Font := Self.Font;
                if (gdSelected in DrawState) and
                  (not (gdFocused in DrawState) or
                  ([goDrawFocusSelected, goRowSelect] * Options <> [])) then
                begin
                  Brush.Color := clHighlight;
                  Font.Color := clHighlightText;
                end
                else
                  Brush.Color := Color;
                FillRect(Where);
              end;
            DrawCell(CurCol, CurRow, Where, DrawState);
            if DefaultDrawing and (gdFixed in DrawState) and Ctl3D and
              ((FrameFlags1 or FrameFlags2) <> 0) then
            begin
              TempRect := Where;
              if (FrameFlags1 and BF_RIGHT) = 0 then
                Inc(TempRect.Right, DrawInfo.Horz.EffectiveLineWidth)
              else if (FrameFlags1 and BF_BOTTOM) = 0 then
                Inc(TempRect.Bottom, DrawInfo.Vert.EffectiveLineWidth);
              DrawEdge(Canvas.Handle, TempRect, BDR_RAISEDINNER, FrameFlags1);
              DrawEdge(Canvas.Handle, TempRect, BDR_RAISEDINNER, FrameFlags2);
            end;
            if DefaultDrawing and not (csDesigning in ComponentState) and
              (gdFocused in DrawState) and
              ([goEditing, goAlwaysShowEditor] * Options <>
              [goEditing, goAlwaysShowEditor])
              and not (goRowSelect in Options) then
            begin
              if not UseRightToLeftAlignment then
                DrawFocusRect(Canvas.Handle, Where)
              else
              begin
                AWhere := Where;
                AWhere.Left := Where.Right;
                AWhere.Right := Where.Left;
                DrawFocusRect(Canvas.Handle, AWhere);
              end;
            end;
          end;
        end;
        Where.Left := Where.Right + DrawInfo.Horz.EffectiveLineWidth;
        Inc(CurCol);
      end;
      Where.Top := Where.Bottom + DrawInfo.Vert.EffectiveLineWidth;
      Inc(CurRow);
    end;
  end;

begin
  if UseRightToLeftAlignment then ChangeGridOrientation(True);

  UpdateRect := Canvas.ClipRect;
  CalcDrawInfo(DrawInfo);
  with DrawInfo do
  begin
    if (Horz.EffectiveLineWidth > 0) or (Vert.EffectiveLineWidth > 0) then
    begin
      { Draw the grid line in the four areas (fixed, fixed), (variable, fixed),
        (fixed, variable) and (variable, variable) }
      LineColor := clSilver;
      MaxStroke := Max(Horz.LastFullVisibleCell - LeftCol + FixedCols,
                        Vert.LastFullVisibleCell - TopRow + FixedRows) + 3;
      PointsList := StackAlloc(MaxStroke * sizeof(TPoint) * 2);
      StrokeList := StackAlloc(MaxStroke * sizeof(Integer));
      FillDWord(StrokeList^, MaxStroke, 2);

      if ColorToRGB(Color) = clSilver then LineColor := clGray;
      DrawLines(goFixedHorzLine in Options, goFixedVertLine in Options,
        0, 0, [0, 0, Horz.FixedBoundary, Vert.FixedBoundary], clBlack, FixedColor);
      DrawLines(goFixedHorzLine in Options, goFixedVertLine in Options,
        LeftCol, 0, [Horz.FixedBoundary, 0, Horz.GridBoundary,
        Vert.FixedBoundary], clBlack, FixedColor);
      DrawLines(goFixedHorzLine in Options, goFixedVertLine in Options,
        0, TopRow, [0, Vert.FixedBoundary, Horz.FixedBoundary,
        Vert.GridBoundary], clBlack, FixedColor);
      DrawLines(goHorzLine in Options, goVertLine in Options, LeftCol,
        TopRow, [Horz.FixedBoundary, Vert.FixedBoundary, Horz.GridBoundary,
        Vert.GridBoundary], LineColor, Color);

      StackFree(StrokeList);
      StackFree(PointsList);
    end;

    { Draw the cells in the four areas }
    Sel := Selection;
    FrameFlags1 := 0;
    FrameFlags2 := 0;
    if goFixedVertLine in Options then
    begin
      FrameFlags1 := BF_RIGHT;
      FrameFlags2 := BF_LEFT;
    end;
    if goFixedHorzLine in Options then
    begin
      FrameFlags1 := FrameFlags1 or BF_BOTTOM;
      FrameFlags2 := FrameFlags2 or BF_TOP;
    end;
    DrawCells(0, 0, 0, 0, Horz.FixedBoundary, Vert.FixedBoundary, FixedColor,
      [gdFixed]);
    DrawCells(LeftCol, 0, Horz.FixedBoundary - FColOffset, 0, Horz.GridBoundary,  //!! clip
      Vert.FixedBoundary, FixedColor, [gdFixed]);
    DrawCells(0, TopRow, 0, Vert.FixedBoundary, Horz.FixedBoundary,
      Vert.GridBoundary, FixedColor, [gdFixed]);
    DrawCells(LeftCol, TopRow, Horz.FixedBoundary - FColOffset,                   //!! clip
      Vert.FixedBoundary, Horz.GridBoundary, Vert.GridBoundary, Color, []);

    if not (csDesigning in ComponentState) and
      (goRowSelect in Options) and DefaultDrawing and Focused then
    begin
      GridRectToScreenRect(GetSelection, FocRect, False);
      if not UseRightToLeftAlignment then
        Canvas.DrawFocusRect(FocRect)
      else
      begin
        AFocRect := FocRect;
        AFocRect.Left := FocRect.Right;
        AFocRect.Right := FocRect.Left;
        DrawFocusRect(Canvas.Handle, AFocRect);
      end;
    end;

    { Fill in area not occupied by cells }
    if Horz.GridBoundary < Horz.GridExtent then
    begin
      Canvas.Brush.Color := Color;
      Canvas.FillRect(Rect(Horz.GridBoundary, 0, Horz.GridExtent, Vert.GridBoundary));
    end;
    if Vert.GridBoundary < Vert.GridExtent then
    begin
      Canvas.Brush.Color := Color;
      Canvas.FillRect(Rect(0, Vert.GridBoundary, Horz.GridExtent, Vert.GridExtent));
    end;
  end;

  if UseRightToLeftAlignment then ChangeGridOrientation(False);
end;

function TCustomGrid.CalcCoordFromPoint(X, Y: Integer;
  const DrawInfo: TGridDrawInfo): TGridCoord;

  function DoCalc(const AxisInfo: TGridAxisDrawInfo; N: Integer): Integer;
  var
    I, Start, Stop: Longint;
    Line: Integer;
  begin
    with AxisInfo do
    begin
      if N < FixedBoundary then
      begin
        Start := 0;
        Stop :=  FixedCellCount - 1;
        Line := 0;
      end
      else
      begin
        Start := FirstGridCell;
        Stop := GridCellCount - 1;
        Line := FixedBoundary;
      end;
      Result := -1;
      for I := Start to Stop do
      begin
        Inc(Line, GetExtent(I) + EffectiveLineWidth);
        if N < Line then
        begin
          Result := I;
          Exit;
        end;
      end;
    end;
  end;

  function DoCalcRightToLeft(const AxisInfo: TGridAxisDrawInfo; N: Integer): Integer;
  var
    I, Start, Stop: Longint;
    Line: Integer;
  begin
    N := ClientWidth - N;
    with AxisInfo do
    begin
      if N < FixedBoundary then
      begin
        Start := 0;
        Stop :=  FixedCellCount - 1;
        Line := ClientWidth;
      end
      else
      begin
        Start := FirstGridCell;
        Stop := GridCellCount - 1;
        Line := FixedBoundary;
      end;
      Result := -1;
      for I := Start to Stop do
      begin
        Inc(Line, GetExtent(I) + EffectiveLineWidth);
        if N < Line then
        begin
          Result := I;
          Exit;
        end;
      end;
    end;
  end;

begin
  if not UseRightToLeftAlignment then
    Result.X := DoCalc(DrawInfo.Horz, X)
  else
    Result.X := DoCalcRightToLeft(DrawInfo.Horz, X);
  Result.Y := DoCalc(DrawInfo.Vert, Y);
end;

procedure TCustomGrid.CalcDrawInfo(var DrawInfo: TGridDrawInfo);
begin
  CalcDrawInfoXY(DrawInfo, ClientWidth, ClientHeight);
end;

procedure TCustomGrid.CalcDrawInfoXY(var DrawInfo: TGridDrawInfo;
  UseWidth, UseHeight: Integer);

  procedure CalcAxis(var AxisInfo: TGridAxisDrawInfo; UseExtent: Integer);
  var
    I: Integer;
  begin
    with AxisInfo do
    begin
      GridExtent := UseExtent;
      GridBoundary := FixedBoundary;
      FullVisBoundary := FixedBoundary;
      LastFullVisibleCell := FirstGridCell;
      for I := FirstGridCell to GridCellCount - 1 do
      begin
        Inc(GridBoundary, GetExtent(I) + EffectiveLineWidth);
        if GridBoundary > GridExtent + EffectiveLineWidth then
        begin
          GridBoundary := GridExtent;
          Break;
        end;
        LastFullVisibleCell := I;
        FullVisBoundary := GridBoundary;
      end;
    end;
  end;

begin
  CalcFixedInfo(DrawInfo);
  CalcAxis(DrawInfo.Horz, UseWidth);
  CalcAxis(DrawInfo.Vert, UseHeight);
end;

procedure TCustomGrid.CalcFixedInfo(var DrawInfo: TGridDrawInfo);

  procedure CalcFixedAxis(var Axis: TGridAxisDrawInfo; LineOptions: TGridOptions;
    FixedCount, FirstCell, CellCount: Integer; GetExtentFunc: TGetExtentsFunc);
  var
    I: Integer;
  begin
    with Axis do
    begin
      if LineOptions * Options = [] then
        EffectiveLineWidth := 0
      else
        EffectiveLineWidth := GridLineWidth;

      FixedBoundary := 0;
      for I := 0 to FixedCount - 1 do
        Inc(FixedBoundary, GetExtentFunc(I) + EffectiveLineWidth);

      FixedCellCount := FixedCount;
      FirstGridCell := FirstCell;
      GridCellCount := CellCount;
      GetExtent := GetExtentFunc;
    end;
  end;

begin
  CalcFixedAxis(DrawInfo.Horz, [goFixedVertLine, goVertLine], FixedCols,
    LeftCol, ColCount, GetColWidths);
  CalcFixedAxis(DrawInfo.Vert, [goFixedHorzLine, goHorzLine], FixedRows,
    TopRow, RowCount, GetRowHeights);
end;

{ Calculates the TopLeft that will put the given Coord in view }
function TCustomGrid.CalcMaxTopLeft(const Coord: TGridCoord;
  const DrawInfo: TGridDrawInfo): TGridCoord;

  function CalcMaxCell(const Axis: TGridAxisDrawInfo; Start: Integer): Integer;
  var
    Line: Integer;
    I, Extent: Longint;
  begin
    Result := Start;
    with Axis do
    begin
      Line := GridExtent + EffectiveLineWidth;
      for I := Start downto FixedCellCount do
      begin
        Extent := GetExtent(I);
        if Extent > 0 then
        begin
          Dec(Line, Extent);
          Dec(Line, EffectiveLineWidth);
          if Line < FixedBoundary then
          begin
            if (Result = Start) and (GetExtent(Start) <= 0) then
              Result := I;
            Break;
          end;
          Result := I;
        end;
      end;
    end;
  end;

begin
  Result.X := CalcMaxCell(DrawInfo.Horz, Coord.X);
  Result.Y := CalcMaxCell(DrawInfo.Vert, Coord.Y);
end;

procedure TCustomGrid.CalcSizingState(X, Y: Integer; var State: TGridState;
  var Index: Longint; var SizingPos, SizingOfs: Integer;
  var FixedInfo: TGridDrawInfo);

  procedure CalcAxisState(const AxisInfo: TGridAxisDrawInfo; Pos: Integer;
    NewState: TGridState);
  var
    I, Line, Back, Range: Integer;
  begin
    if UseRightToLeftAlignment then
      Pos := ClientWidth - Pos;
    with AxisInfo do
    begin
      Line := FixedBoundary;
      Range := EffectiveLineWidth;
      Back := 0;
      if Range < 7 then
      begin
        Range := 7;
        Back := (Range - EffectiveLineWidth) shr 1;
      end;
      for I := FirstGridCell to GridCellCount - 1 do
      begin
        Inc(Line, GetExtent(I));
        if Line > GridBoundary then Break;
        if (Pos >= Line - Back) and (Pos <= Line - Back + Range) then
        begin
          State := NewState;
          SizingPos := Line;
          SizingOfs := Line - Pos;
          Index := I;
          Exit;
        end;
        Inc(Line, EffectiveLineWidth);
      end;
      if (GridBoundary = GridExtent) and (Pos >= GridExtent - Back)
        and (Pos <= GridExtent) then
      begin
        State := NewState;
        SizingPos := GridExtent;
        SizingOfs := GridExtent - Pos;
        Index := LastFullVisibleCell + 1;
      end;
    end;
  end;

  function XOutsideHorzFixedBoundary: Boolean;
  begin
    with FixedInfo do
      if not UseRightToLeftAlignment then
        Result := X > Horz.FixedBoundary
      else
        Result := X < ClientWidth - Horz.FixedBoundary;
  end;

  function XOutsideOrEqualHorzFixedBoundary: Boolean;
  begin
    with FixedInfo do
      if not UseRightToLeftAlignment then
        Result := X >= Horz.FixedBoundary
      else
        Result := X <= ClientWidth - Horz.FixedBoundary;
  end;


var
  EffectiveOptions: TGridOptions;
begin
  State := gsNormal;
  Index := -1;
  EffectiveOptions := Options;
  if csDesigning in ComponentState then
    EffectiveOptions := EffectiveOptions + DesignOptionsBoost;
  if [goColSizing, goRowSizing] * EffectiveOptions <> [] then
    with FixedInfo do
    begin
      Vert.GridExtent := ClientHeight;
      Horz.GridExtent := ClientWidth;
      if (XOutsideHorzFixedBoundary) and (goColSizing in EffectiveOptions) then
      begin
        if Y >= Vert.FixedBoundary then Exit;
        CalcAxisState(Horz, X, gsColSizing);
      end
      else if (Y > Vert.FixedBoundary) and (goRowSizing in EffectiveOptions) then
      begin
        if XOutsideOrEqualHorzFixedBoundary then Exit;
        CalcAxisState(Vert, Y, gsRowSizing);
      end;
    end;
end;

procedure TCustomGrid.ChangeGridOrientation(RightToLeftOrientation: Boolean);
var
  Org: TPoint;
  Ext: TPoint;
begin
  if RightToLeftOrientation then
  begin
    Org := Point(ClientWidth,0);
    Ext := Point(-1,1);
    SetMapMode(Canvas.Handle, mm_Anisotropic);
    SetWindowOrgEx(Canvas.Handle, Org.X, Org.Y, nil);
    SetViewportExtEx(Canvas.Handle, ClientWidth, ClientHeight, nil);
    SetWindowExtEx(Canvas.Handle, Ext.X*ClientWidth, Ext.Y*ClientHeight, nil);
  end
  else
  begin
    Org := Point(0,0);
    Ext := Point(1,1);
    SetMapMode(Canvas.Handle, mm_Anisotropic);
    SetWindowOrgEx(Canvas.Handle, Org.X, Org.Y, nil);
    SetViewportExtEx(Canvas.Handle, ClientWidth, ClientHeight, nil);
    SetWindowExtEx(Canvas.Handle, Ext.X*ClientWidth, Ext.Y*ClientHeight, nil);
  end;
end;

procedure TCustomGrid.ChangeSize(NewColCount, NewRowCount: Longint);
var
  OldColCount, OldRowCount: Longint;
  OldDrawInfo: TGridDrawInfo;

  procedure MinRedraw(const OldInfo, NewInfo: TGridAxisDrawInfo; Axis: Integer);
  var
    R: TRect;
    First: Integer;
  begin
    First := Min(OldInfo.LastFullVisibleCell, NewInfo.LastFullVisibleCell);
    // Get the rectangle around the leftmost or topmost cell in the target range.
    R := CellRect(First and not Axis, First and Axis);
    R.Bottom := Height;
    R.Right := Width;
    Windows.InvalidateRect(Handle, @R, False);
  end;

  procedure DoChange;
  var
    Coord: TGridCoord;
    NewDrawInfo: TGridDrawInfo;
  begin
    if FColWidths <> nil then
      UpdateExtents(FColWidths, ColCount, DefaultColWidth);
    if FTabStops <> nil then
      UpdateExtents(FTabStops, ColCount, Integer(True));
    if FRowHeights <> nil then
      UpdateExtents(FRowHeights, RowCount, DefaultRowHeight);
    Coord := FCurrent;
    if Row >= RowCount then Coord.Y := RowCount - 1;
    if Col >= ColCount then Coord.X := ColCount - 1;
    if (FCurrent.X <> Coord.X) or (FCurrent.Y <> Coord.Y) then
      MoveCurrent(Coord.X, Coord.Y, True, True);
    if (FAnchor.X <> Coord.X) or (FAnchor.Y <> Coord.Y) then
      MoveAnchor(Coord);
    if VirtualView or
      (LeftCol <> OldDrawInfo.Horz.FirstGridCell) or
      (TopRow <> OldDrawInfo.Vert.FirstGridCell) then
      InvalidateGrid
    else if HandleAllocated then
    begin
      CalcDrawInfo(NewDrawInfo);
      MinRedraw(OldDrawInfo.Horz, NewDrawInfo.Horz, 0);
      MinRedraw(OldDrawInfo.Vert, NewDrawInfo.Vert, -1);
    end;
    UpdateScrollRange;
    SizeChanged(OldColCount, OldRowCount);
  end;

begin
  if HandleAllocated then
    CalcDrawInfo(OldDrawInfo);
  OldColCount := FColCount;
  OldRowCount := FRowCount;
  FColCount := NewColCount;
  FRowCount := NewRowCount;
  if FixedCols > NewColCount then FFixedCols := NewColCount - 1;
  if FixedRows > NewRowCount then FFixedRows := NewRowCount - 1;
  try
    DoChange;
  except
    { Could not change size so try to clean up by setting the size back }
    FColCount := OldColCount;
    FRowCount := OldRowCount;
    DoChange;
    InvalidateGrid;
    raise;
  end;
end;

{ Will move TopLeft so that Coord is in view }
procedure TCustomGrid.ClampInView(const Coord: TGridCoord);
var
  DrawInfo: TGridDrawInfo;
  MaxTopLeft: TGridCoord;
  OldTopLeft: TGridCoord;
begin
  if not HandleAllocated then Exit;
  CalcDrawInfo(DrawInfo);
  with DrawInfo, Coord do
  begin
    if (X > Horz.LastFullVisibleCell) or
      (Y > Vert.LastFullVisibleCell) or (X < LeftCol) or (Y < TopRow) then
    begin
      OldTopLeft := FTopLeft;
      MaxTopLeft := CalcMaxTopLeft(Coord, DrawInfo);
      Update;
      if X < LeftCol then FTopLeft.X := X
      else if X > Horz.LastFullVisibleCell then FTopLeft.X := MaxTopLeft.X;
      if Y < TopRow then FTopLeft.Y := Y
      else if Y > Vert.LastFullVisibleCell then FTopLeft.Y := MaxTopLeft.Y;
      TopLeftMoved(OldTopLeft);
    end;
  end;
end;

procedure TCustomGrid.DrawSizingLine(const DrawInfo: TGridDrawInfo);
var
  OldPen: TPen;
begin
  OldPen := TPen.Create;
  try
    with Canvas, DrawInfo do
    begin
      OldPen.Assign(Pen);
      Pen.Style := psDot;
      Pen.Mode := pmXor;
      Pen.Width := 1;
      try
        if FGridState = gsRowSizing then
        begin
          MoveTo(0, FSizingPos);
          LineTo(Horz.GridBoundary, FSizingPos);
        end
        else
        begin
          MoveTo(FSizingPos, 0);
          LineTo(FSizingPos, Vert.GridBoundary);
        end;
      finally
        Pen := OldPen;
      end;
    end;
  finally
    OldPen.Free;
  end;
end;

procedure TCustomGrid.DrawMove;
var
  OldPen: TPen;
  Pos: Integer;
  R: TRect;
begin
  OldPen := TPen.Create;
  try
    with Canvas do
    begin
      OldPen.Assign(Pen);
      try
        Pen.Style := psDot;
        Pen.Mode := pmXor;
        Pen.Width := 5;
        if FGridState = gsRowMoving then
        begin
          R := CellRect(0, FMovePos);
          if FMovePos > FMoveIndex then
            Pos := R.Bottom else
            Pos := R.Top;
          MoveTo(0, Pos);
          LineTo(ClientWidth, Pos);
        end
        else
        begin
          R := CellRect(FMovePos, 0);
          if FMovePos > FMoveIndex then
            if not UseRightToLeftAlignment then
              Pos := R.Right
            else
              Pos := R.Left
          else
            if not UseRightToLeftAlignment then
              Pos := R.Left
            else
              Pos := R.Right;
          MoveTo(Pos, 0);
          LineTo(Pos, ClientHeight);
        end;
      finally
        Canvas.Pen := OldPen;
      end;
    end;
  finally
    OldPen.Free;
  end;
end;

procedure TCustomGrid.FocusCell(ACol, ARow: Longint; MoveAnchor: Boolean);
begin
  MoveCurrent(ACol, ARow, MoveAnchor, True);
  UpdateEdit;
  Click;
end;

procedure TCustomGrid.GridRectToScreenRect(GridRect: TGridRect;
  var ScreenRect: TRect; IncludeLine: Boolean);

  function LinePos(const AxisInfo: TGridAxisDrawInfo; Line: Integer): Integer;
  var
    Start, I: Longint;
  begin
    with AxisInfo do
    begin
      Result := 0;
      if Line < FixedCellCount then
        Start := 0
      else
      begin
        if Line >= FirstGridCell then
          Result := FixedBoundary;
        Start := FirstGridCell;
      end;
      for I := Start to Line - 1 do
      begin
        Inc(Result, GetExtent(I) + EffectiveLineWidth);
        if Result > GridExtent then
        begin
          Result := 0;
          Exit;
        end;
      end;
    end;
  end;

  function CalcAxis(const AxisInfo: TGridAxisDrawInfo;
    GridRectMin, GridRectMax: Integer;
    var ScreenRectMin, ScreenRectMax: Integer): Boolean;
  begin
    Result := False;
    with AxisInfo do
    begin
      if (GridRectMin >= FixedCellCount) and (GridRectMin < FirstGridCell) then
        if GridRectMax < FirstGridCell then
        begin
          FillChar(ScreenRect, SizeOf(ScreenRect), 0); { erase partial results }
          Exit;
        end
        else
          GridRectMin := FirstGridCell;
      if GridRectMax > LastFullVisibleCell then
      begin
        GridRectMax := LastFullVisibleCell;
        if GridRectMax < GridCellCount - 1 then Inc(GridRectMax);
        if LinePos(AxisInfo, GridRectMax) = 0 then
          Dec(GridRectMax);
      end;

      ScreenRectMin := LinePos(AxisInfo, GridRectMin);
      ScreenRectMax := LinePos(AxisInfo, GridRectMax);
      if ScreenRectMax = 0 then
        ScreenRectMax := ScreenRectMin + GetExtent(GridRectMin)
      else
        Inc(ScreenRectMax, GetExtent(GridRectMax));
      if ScreenRectMax > GridExtent then
        ScreenRectMax := GridExtent;
      if IncludeLine then Inc(ScreenRectMax, EffectiveLineWidth);
    end;
    Result := True;
  end;

var
  DrawInfo: TGridDrawInfo;
  Hold: Integer;
begin
  FillChar(ScreenRect, SizeOf(ScreenRect), 0);
  if (GridRect.Left > GridRect.Right) or (GridRect.Top > GridRect.Bottom) then
    Exit;
  CalcDrawInfo(DrawInfo);
  with DrawInfo do
  begin
    if GridRect.Left > Horz.LastFullVisibleCell + 1 then Exit;
    if GridRect.Top > Vert.LastFullVisibleCell + 1 then Exit;

    if CalcAxis(Horz, GridRect.Left, GridRect.Right, ScreenRect.Left,
      ScreenRect.Right) then
    begin
      CalcAxis(Vert, GridRect.Top, GridRect.Bottom, ScreenRect.Top,
        ScreenRect.Bottom);
    end;
  end;
  if UseRightToLeftAlignment and (Canvas.CanvasOrientation = coLeftToRight) then
  begin
    Hold := ScreenRect.Left;
    ScreenRect.Left := ClientWidth - ScreenRect.Right;
    ScreenRect.Right := ClientWidth - Hold;
  end;
end;

procedure TCustomGrid.Initialize;
begin
  FTopLeft.X := FixedCols;
  FTopLeft.Y := FixedRows;
  FCurrent := FTopLeft;
  FAnchor := FCurrent;
  if goRowSelect in Options then FAnchor.X := ColCount - 1;
end;

procedure TCustomGrid.InvalidateCell(ACol, ARow: Longint);
var
  Rect: TGridRect;
begin
  Rect.Top := ARow;
  Rect.Left := ACol;
  Rect.Bottom := ARow;
  Rect.Right := ACol;
  InvalidateRect(Rect);
end;

procedure TCustomGrid.InvalidateCol(ACol: Longint);
var
  Rect: TGridRect;
begin
  if not HandleAllocated then Exit;
  Rect.Top := 0;
  Rect.Left := ACol;
  Rect.Bottom := VisibleRowCount+1;
  Rect.Right := ACol;
  InvalidateRect(Rect);
end;

procedure TCustomGrid.InvalidateRow(ARow: Longint);
var
  Rect: TGridRect;
begin
  if not HandleAllocated then Exit;
  Rect.Top := ARow;
  Rect.Left := 0;
  Rect.Bottom := ARow;
  Rect.Right := VisibleColCount+1;
  InvalidateRect(Rect);
end;

procedure TCustomGrid.InvalidateGrid;
begin
  Invalidate;
end;

procedure TCustomGrid.InvalidateRect(ARect: TGridRect);
var
  InvalidRect: TRect;
begin
  if not HandleAllocated then Exit;
  GridRectToScreenRect(ARect, InvalidRect, True);
  Windows.InvalidateRect(Handle, @InvalidRect, False);
end;

procedure TCustomGrid.ModifyScrollBar(ScrollBar, ScrollCode, Pos: Cardinal;
  UseRightToLeft: Boolean);
var
  NewTopLeft, MaxTopLeft: TGridCoord;
  DrawInfo: TGridDrawInfo;
  RTLFactor: Integer;

  function Min: Longint;
  begin
    if ScrollBar = SB_HORZ then Result := FixedCols
    else Result := FixedRows;
  end;

  function Max: Longint;
  begin
    if ScrollBar = SB_HORZ then Result := MaxTopLeft.X
    else Result := MaxTopLeft.Y;
  end;

  function PageUp: Longint;
  var
    MaxTopLeft: TGridCoord;
  begin
    MaxTopLeft := CalcMaxTopLeft(FTopLeft, DrawInfo);
    if ScrollBar = SB_HORZ then
      Result := FTopLeft.X - MaxTopLeft.X else
      Result := FTopLeft.Y - MaxTopLeft.Y;
    if Result < 1 then Result := 1;
  end;

  function PageDown: Longint;
  var
    DrawInfo: TGridDrawInfo;
  begin
    CalcDrawInfo(DrawInfo);
    with DrawInfo do
      if ScrollBar = SB_HORZ then
        Result := Horz.LastFullVisibleCell - FTopLeft.X else
        Result := Vert.LastFullVisibleCell - FTopLeft.Y;
    if Result < 1 then Result := 1;
  end;

  function CalcScrollBar(Value, ARTLFactor: Longint): Longint;
  begin
    Result := Value;
    case ScrollCode of
      SB_LINEUP:
        Dec(Result, ARTLFactor);
      SB_LINEDOWN:
        Inc(Result, ARTLFactor);
      SB_PAGEUP:
        Dec(Result, PageUp * ARTLFactor);
      SB_PAGEDOWN:
        Inc(Result, PageDown * ARTLFactor);
      SB_THUMBPOSITION, SB_THUMBTRACK:
        if (goThumbTracking in Options) or (ScrollCode = SB_THUMBPOSITION) then
        begin
          if (not UseRightToLeftAlignment) or (ARTLFactor = 1) then
            Result := Min + LongMulDiv(Pos, Max - Min, MaxShortInt)
          else
            Result := Max - LongMulDiv(Pos, Max - Min, MaxShortInt);
        end;
      SB_BOTTOM:
        Result := Max;
      SB_TOP:
        Result := Min;
    end;
  end;

  procedure ModifyPixelScrollBar(Code, Pos: Cardinal);
  var
    NewOffset: Integer;
    OldOffset: Integer;
    R: TGridRect;
    GridSpace, ColWidth: Integer;
  begin
    NewOffset := FColOffset;
    ColWidth := ColWidths[DrawInfo.Horz.FirstGridCell];
    GridSpace := ClientWidth - DrawInfo.Horz.FixedBoundary;
    case Code of
      SB_LINEUP: Dec(NewOffset, Canvas.TextWidth('0') * RTLFactor);
      SB_LINEDOWN: Inc(NewOffset, Canvas.TextWidth('0') * RTLFactor);
      SB_PAGEUP: Dec(NewOffset, GridSpace * RTLFactor);
      SB_PAGEDOWN: Inc(NewOffset, GridSpace * RTLFactor);
      SB_THUMBPOSITION,
      SB_THUMBTRACK:
        if (goThumbTracking in Options) or (Code = SB_THUMBPOSITION) then
        begin
          if not UseRightToLeftAlignment then
            NewOffset := Pos
          else
            NewOffset := Max - Integer(Pos);
        end;
      SB_BOTTOM: NewOffset := 0;
      SB_TOP: NewOffset := ColWidth - GridSpace;
    end;
    if NewOffset < 0 then
      NewOffset := 0
    else if NewOffset >= ColWidth - GridSpace then
      NewOffset := ColWidth - GridSpace;
    if NewOffset <> FColOffset then
    begin
      OldOffset := FColOffset;
      FColOffset := NewOffset;
      ScrollData(OldOffset - NewOffset, 0);
      FillChar(R, SizeOf(R), 0);
      R.Bottom := FixedRows;
      InvalidateRect(R);
      Update;
      UpdateScrollPos;
    end;
  end;

var
  Temp: Longint;
begin
  if (not UseRightToLeftAlignment) or (not UseRightToLeft) then
    RTLFactor := 1
  else
    RTLFactor := -1;
  if Visible and CanFocus and TabStop and not (csDesigning in ComponentState) then
    SetFocus;
  CalcDrawInfo(DrawInfo);
  if (ScrollBar = SB_HORZ) and (ColCount = 1) then
  begin
    ModifyPixelScrollBar(ScrollCode, Pos);
    Exit;
  end;
  MaxTopLeft.X := ColCount - 1;
  MaxTopLeft.Y := RowCount - 1;
  MaxTopLeft := CalcMaxTopLeft(MaxTopLeft, DrawInfo);
  NewTopLeft := FTopLeft;
  if ScrollBar = SB_HORZ then
    repeat
      Temp := NewTopLeft.X;
      NewTopLeft.X := CalcScrollBar(NewTopLeft.X, RTLFactor);
    until (NewTopLeft.X <= FixedCols) or (NewTopLeft.X >= MaxTopLeft.X)        
      or (ColWidths[NewTopLeft.X] > 0) or (Temp = NewTopLeft.X)
  else
    repeat
      Temp := NewTopLeft.Y;
      NewTopLeft.Y := CalcScrollBar(NewTopLeft.Y, 1);
    until (NewTopLeft.Y <= FixedRows) or (NewTopLeft.Y >= MaxTopLeft.Y)
      or (RowHeights[NewTopLeft.Y] > 0) or (Temp = NewTopLeft.Y);
  NewTopLeft.X := Math.Max(FixedCols, Math.Min(MaxTopLeft.X, NewTopLeft.X));
  NewTopLeft.Y := Math.Max(FixedRows, Math.Min(MaxTopLeft.Y, NewTopLeft.Y));
  if (NewTopLeft.X <> FTopLeft.X) or (NewTopLeft.Y <> FTopLeft.Y) then
    MoveTopLeft(NewTopLeft.X, NewTopLeft.Y);
end;

procedure TCustomGrid.MoveAdjust(var CellPos: Longint; FromIndex, ToIndex: Longint);
var
  Min, Max: Longint;
begin
  if CellPos = FromIndex then CellPos := ToIndex
  else
  begin
    Min := FromIndex;
    Max := ToIndex;
    if FromIndex > ToIndex then
    begin
      Min := ToIndex;
      Max := FromIndex;
    end;
    if (CellPos >= Min) and (CellPos <= Max) then
      if FromIndex > ToIndex then
        Inc(CellPos) else
        Dec(CellPos);
  end;
end;

procedure TCustomGrid.MoveAnchor(const NewAnchor: TGridCoord);
var
  OldSel: TGridRect;
begin
  if [goRangeSelect, goEditing] * Options = [goRangeSelect] then
  begin
    OldSel := Selection;
    FAnchor := NewAnchor;
    if goRowSelect in Options then FAnchor.X := ColCount - 1;
    ClampInView(NewAnchor);
    SelectionMoved(OldSel);
  end
  else MoveCurrent(NewAnchor.X, NewAnchor.Y, True, True);
end;

procedure TCustomGrid.MoveCurrent(ACol, ARow: Longint; MoveAnchor,
  Show: Boolean);
var
  OldSel: TGridRect;
  OldCurrent: TGridCoord;
begin
  if (ACol < 0) or (ARow < 0) or (ACol >= ColCount) or (ARow >= RowCount) then
    InvalidOp(SIndexOutOfRange);
  if SelectCell(ACol, ARow) then
  begin
    OldSel := Selection;
    OldCurrent := FCurrent;
    FCurrent.X := ACol;
    FCurrent.Y := ARow;
    if not (goAlwaysShowEditor in Options) then HideEditor;
    if MoveAnchor or not (goRangeSelect in Options) then
    begin
      FAnchor := FCurrent;
      if goRowSelect in Options then FAnchor.X := ColCount - 1;
    end;
    if goRowSelect in Options then FCurrent.X := FixedCols;
    if Show then ClampInView(FCurrent);
    SelectionMoved(OldSel);
    with OldCurrent do InvalidateCell(X, Y);
    with FCurrent do InvalidateCell(ACol, ARow);
  end;
end;

procedure TCustomGrid.MoveTopLeft(ALeft, ATop: Longint);
var
  OldTopLeft: TGridCoord;
begin
  if (ALeft = FTopLeft.X) and (ATop = FTopLeft.Y) then Exit;
  Update;
  OldTopLeft := FTopLeft;
  FTopLeft.X := ALeft;
  FTopLeft.Y := ATop;
  TopLeftMoved(OldTopLeft);
end;

procedure TCustomGrid.ResizeCol(Index: Longint; OldSize, NewSize: Integer);
begin
  InvalidateGrid;
end;

procedure TCustomGrid.ResizeRow(Index: Longint; OldSize, NewSize: Integer);
begin
  InvalidateGrid;
end;

procedure TCustomGrid.SelectionMoved(const OldSel: TGridRect);
var
  OldRect, NewRect: TRect;
  AXorRects: TXorRects;
  I: Integer;
begin
  if not HandleAllocated then Exit;
  GridRectToScreenRect(OldSel, OldRect, True);
  GridRectToScreenRect(Selection, NewRect, True);
  XorRects(OldRect, NewRect, AXorRects);
  for I := Low(AXorRects) to High(AXorRects) do
    Windows.InvalidateRect(Handle, @AXorRects[I], False);
end;

procedure TCustomGrid.ScrollDataInfo(DX, DY: Integer;
  var DrawInfo: TGridDrawInfo);
var
  ScrollArea: TRect;
  ScrollFlags: Integer;
begin
  with DrawInfo do
  begin
    ScrollFlags := SW_INVALIDATE;
    if not DefaultDrawing then
      ScrollFlags := ScrollFlags or SW_ERASE;
    { Scroll the area }
    if DY = 0 then
    begin
      { Scroll both the column titles and data area at the same time }
      if not UseRightToLeftAlignment then
        ScrollArea := Rect(Horz.FixedBoundary, 0, Horz.GridExtent, Vert.GridExtent)
      else
      begin
        ScrollArea := Rect(ClientWidth - Horz.GridExtent, 0, ClientWidth - Horz.FixedBoundary, Vert.GridExtent);
        DX := -DX;
      end;
      ScrollWindowEx(Handle, DX, 0, @ScrollArea, @ScrollArea, 0, nil, ScrollFlags);
    end
    else if DX = 0 then
    begin
      { Scroll both the row titles and data area at the same time }
      ScrollArea := Rect(0, Vert.FixedBoundary, Horz.GridExtent, Vert.GridExtent);
      ScrollWindowEx(Handle, 0, DY, @ScrollArea, @ScrollArea, 0, nil, ScrollFlags);
    end
    else
    begin
      { Scroll titles and data area separately }
      { Column titles }
      ScrollArea := Rect(Horz.FixedBoundary, 0, Horz.GridExtent, Vert.FixedBoundary);
      ScrollWindowEx(Handle, DX, 0, @ScrollArea, @ScrollArea, 0, nil, ScrollFlags);
      { Row titles }
      ScrollArea := Rect(0, Vert.FixedBoundary, Horz.FixedBoundary, Vert.GridExtent);
      ScrollWindowEx(Handle, 0, DY, @ScrollArea, @ScrollArea, 0, nil, ScrollFlags);
      { Data area }
      ScrollArea := Rect(Horz.FixedBoundary, Vert.FixedBoundary, Horz.GridExtent,
        Vert.GridExtent);
      ScrollWindowEx(Handle, DX, DY, @ScrollArea, @ScrollArea, 0, nil, ScrollFlags);
    end;
  end;
  if goRowSelect in Options then
    InvalidateRect(Selection);
end;

procedure TCustomGrid.ScrollData(DX, DY: Integer);
var
  DrawInfo: TGridDrawInfo;
begin
  CalcDrawInfo(DrawInfo);
  ScrollDataInfo(DX, DY, DrawInfo);
end;

procedure TCustomGrid.TopLeftMoved(const OldTopLeft: TGridCoord);

  function CalcScroll(const AxisInfo: TGridAxisDrawInfo;
    OldPos, CurrentPos: Integer; var Amount: Longint): Boolean;
  var
    Start, Stop: Longint;
    I: Longint;
  begin
    Result := False;
    with AxisInfo do
    begin
      if OldPos < CurrentPos then
      begin
        Start := OldPos;
        Stop := CurrentPos;
      end
      else
      begin
        Start := CurrentPos;
        Stop := OldPos;
      end;
      Amount := 0;
      for I := Start to Stop - 1 do
      begin
        Inc(Amount, GetExtent(I) + EffectiveLineWidth);
        if Amount > (GridBoundary - FixedBoundary) then
        begin
          { Scroll amount too big, redraw the whole thing }
          InvalidateGrid;
          Exit;
        end;
      end;
      if OldPos < CurrentPos then Amount := -Amount;
    end;
    Result := True;
  end;

var
  DrawInfo: TGridDrawInfo;
  Delta: TGridCoord;
begin
  UpdateScrollPos;
  CalcDrawInfo(DrawInfo);
  if CalcScroll(DrawInfo.Horz, OldTopLeft.X, FTopLeft.X, Delta.X) and
    CalcScroll(DrawInfo.Vert, OldTopLeft.Y, FTopLeft.Y, Delta.Y) then
    ScrollDataInfo(Delta.X, Delta.Y, DrawInfo);
  TopLeftChanged;
end;

procedure TCustomGrid.UpdateScrollPos;
var
  DrawInfo: TGridDrawInfo;
  MaxTopLeft: TGridCoord;
  GridSpace, ColWidth: Integer;

  procedure SetScroll(Code: Word; Value: Integer);
  begin
    if UseRightToLeftAlignment and (Code = SB_HORZ) then
      if ColCount <> 1 then Value := MaxShortInt - Value
      else                  Value := (ColWidth - GridSpace) - Value;
    if GetScrollPos(Handle, Code) <> Value then
      SetScrollPos(Handle, Code, Value, True);
  end;

begin
  if (not HandleAllocated) or (ScrollBars = ssNone) then Exit;
  CalcDrawInfo(DrawInfo);
  MaxTopLeft.X := ColCount - 1;
  MaxTopLeft.Y := RowCount - 1;
  MaxTopLeft := CalcMaxTopLeft(MaxTopLeft, DrawInfo);
  if ScrollBars in [ssHorizontal, ssBoth] then
    if ColCount = 1 then
    begin
      ColWidth := ColWidths[DrawInfo.Horz.FirstGridCell];
      GridSpace := ClientWidth - DrawInfo.Horz.FixedBoundary;
      if (FColOffset > 0) and (GridSpace > (ColWidth - FColOffset)) then
        ModifyScrollbar(SB_HORZ, SB_THUMBPOSITION, ColWidth - GridSpace, True)
      else
        SetScroll(SB_HORZ, FColOffset)
    end
    else
      SetScroll(SB_HORZ, LongMulDiv(FTopLeft.X - FixedCols, MaxShortInt,
        MaxTopLeft.X - FixedCols));
  if ScrollBars in [ssVertical, ssBoth] then
    SetScroll(SB_VERT, LongMulDiv(FTopLeft.Y - FixedRows, MaxShortInt,
      MaxTopLeft.Y - FixedRows));
end;

procedure TCustomGrid.UpdateScrollRange;
var
  MaxTopLeft, OldTopLeft: TGridCoord;
  DrawInfo: TGridDrawInfo;
  OldScrollBars: TScrollStyle;
  Updated: Boolean;

  procedure DoUpdate;
  begin
    if not Updated then
    begin
      Update;
      Updated := True;
    end;
  end;

  function ScrollBarVisible(Code: Word): Boolean;
  var
    Min, Max: Integer;
  begin
    Result := False;
    if (ScrollBars = ssBoth) or
      ((Code = SB_HORZ) and (ScrollBars = ssHorizontal)) or
      ((Code = SB_VERT) and (ScrollBars = ssVertical)) then
    begin
      GetScrollRange(Handle, Code, Min, Max);
      Result := Min <> Max;
    end;
  end;

  procedure CalcSizeInfo;
  begin
    CalcDrawInfoXY(DrawInfo, DrawInfo.Horz.GridExtent, DrawInfo.Vert.GridExtent);
    MaxTopLeft.X := ColCount - 1;
    MaxTopLeft.Y := RowCount - 1;
    MaxTopLeft := CalcMaxTopLeft(MaxTopLeft, DrawInfo);
  end;

  procedure SetAxisRange(var Max, Old, Current: Longint; Code: Word;
    Fixeds: Integer);
  begin
    CalcSizeInfo;
    if Fixeds < Max then
      SetScrollRange(Handle, Code, 0, MaxShortInt, True)
    else
      SetScrollRange(Handle, Code, 0, 0, True);
    if Old > Max then
    begin
      DoUpdate;
      Current := Max;
    end;
  end;

  procedure SetHorzRange;
  var
    Range: Integer;
  begin
    if OldScrollBars in [ssHorizontal, ssBoth] then
      if ColCount = 1 then
      begin
        Range := ColWidths[0] - ClientWidth;
        if Range < 0 then Range := 0;
        SetScrollRange(Handle, SB_HORZ, 0, Range, True);
      end
      else
        SetAxisRange(MaxTopLeft.X, OldTopLeft.X, FTopLeft.X, SB_HORZ, FixedCols);
  end;

  procedure SetVertRange;
  begin
    if OldScrollBars in [ssVertical, ssBoth] then
      SetAxisRange(MaxTopLeft.Y, OldTopLeft.Y, FTopLeft.Y, SB_VERT, FixedRows);
  end;

begin
  if (ScrollBars = ssNone) or not HandleAllocated or not Showing then Exit;
  with DrawInfo do
  begin
    Horz.GridExtent := ClientWidth;
    Vert.GridExtent := ClientHeight;
    { Ignore scroll bars for initial calculation }
    if ScrollBarVisible(SB_HORZ) then
      Inc(Vert.GridExtent, GetSystemMetrics(SM_CYHSCROLL));
    if ScrollBarVisible(SB_VERT) then
      Inc(Horz.GridExtent, GetSystemMetrics(SM_CXVSCROLL));
  end;
  OldTopLeft := FTopLeft;
  { Temporarily mark us as not having scroll bars to avoid recursion }
  OldScrollBars := FScrollBars;
  FScrollBars := ssNone;
  Updated := False;
  try
    { Update scrollbars }
    SetHorzRange;
    DrawInfo.Vert.GridExtent := ClientHeight;
    SetVertRange;
    if DrawInfo.Horz.GridExtent <> ClientWidth then
    begin
      DrawInfo.Horz.GridExtent := ClientWidth;
      SetHorzRange;
    end;
  finally
    FScrollBars := OldScrollBars;
  end;
  UpdateScrollPos;
  if (FTopLeft.X <> OldTopLeft.X) or (FTopLeft.Y <> OldTopLeft.Y) then
    TopLeftMoved(OldTopLeft);
end;

function TCustomGrid.CreateEditor: TInplaceEdit;
begin
  Result := TInplaceEdit.Create(Self);
end;

procedure TCustomGrid.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  with Params do
  begin
    Style := Style or WS_TABSTOP;
    if FScrollBars in [ssVertical, ssBoth] then Style := Style or WS_VSCROLL;
    if FScrollBars in [ssHorizontal, ssBoth] then Style := Style or WS_HSCROLL;
    WindowClass.style := CS_DBLCLKS;
    if FBorderStyle = bsSingle then
      if NewStyleControls and Ctl3D then
      begin
        Style := Style and not WS_BORDER;
        ExStyle := ExStyle or WS_EX_CLIENTEDGE;
      end
      else
        Style := Style or WS_BORDER;
  end;
end;

procedure TCustomGrid.KeyDown(var Key: Word; Shift: TShiftState);
var
  NewTopLeft, NewCurrent, MaxTopLeft: TGridCoord;
  DrawInfo: TGridDrawInfo;
  PageWidth, PageHeight: Integer;
  RTLFactor: Integer;
  NeedsInvalidating: Boolean;

  procedure CalcPageExtents;
  begin
    CalcDrawInfo(DrawInfo);
    PageWidth := DrawInfo.Horz.LastFullVisibleCell - LeftCol;
    if PageWidth < 1 then PageWidth := 1;
    PageHeight := DrawInfo.Vert.LastFullVisibleCell - TopRow;
    if PageHeight < 1 then PageHeight := 1;
  end;

  procedure Restrict(var Coord: TGridCoord; MinX, MinY, MaxX, MaxY: Longint);
  begin
    with Coord do
    begin
      if X > MaxX then X := MaxX
      else if X < MinX then X := MinX;
      if Y > MaxY then Y := MaxY
      else if Y < MinY then Y := MinY;
    end;
  end;

begin
  inherited KeyDown(Key, Shift);
  NeedsInvalidating := False;
  if not CanGridAcceptKey(Key, Shift) then Key := 0;
  if not UseRightToLeftAlignment then
    RTLFactor := 1
  else
    RTLFactor := -1;
  NewCurrent := FCurrent;
  NewTopLeft := FTopLeft;
  CalcPageExtents;
  if ssCtrl in Shift then
    case Key of
      VK_UP: Dec(NewTopLeft.Y);
      VK_DOWN: Inc(NewTopLeft.Y);
      VK_LEFT:
        if not (goRowSelect in Options) then
        begin
          Dec(NewCurrent.X, PageWidth * RTLFactor);
          Dec(NewTopLeft.X, PageWidth * RTLFactor);
        end;
      VK_RIGHT:
        if not (goRowSelect in Options) then
        begin
          Inc(NewCurrent.X, PageWidth * RTLFactor);
          Inc(NewTopLeft.X, PageWidth * RTLFactor);
        end;
      VK_PRIOR: NewCurrent.Y := TopRow;
      VK_NEXT: NewCurrent.Y := DrawInfo.Vert.LastFullVisibleCell;
      VK_HOME:
        begin
          NewCurrent.X := FixedCols;
          NewCurrent.Y := FixedRows;
          NeedsInvalidating := UseRightToLeftAlignment;
        end;
      VK_END:
        begin
          NewCurrent.X := ColCount - 1;
          NewCurrent.Y := RowCount - 1;
          NeedsInvalidating := UseRightToLeftAlignment;
        end;
    end
  else
    case Key of
      VK_UP: Dec(NewCurrent.Y);
      VK_DOWN: Inc(NewCurrent.Y);
      VK_LEFT:
        if goRowSelect in Options then
          Dec(NewCurrent.Y, RTLFactor) else
          Dec(NewCurrent.X, RTLFactor);
      VK_RIGHT:
        if goRowSelect in Options then
          Inc(NewCurrent.Y, RTLFactor) else
          Inc(NewCurrent.X, RTLFactor);
      VK_NEXT:
        begin
          Inc(NewCurrent.Y, PageHeight);
          Inc(NewTopLeft.Y, PageHeight);
        end;
      VK_PRIOR:
        begin
          Dec(NewCurrent.Y, PageHeight);
          Dec(NewTopLeft.Y, PageHeight);
        end;
      VK_HOME:
        if goRowSelect in Options then
          NewCurrent.Y := FixedRows else
          NewCurrent.X := FixedCols;
      VK_END:
        if goRowSelect in Options then
          NewCurrent.Y := RowCount - 1 else
          NewCurrent.X := ColCount - 1;
      VK_TAB:
        if not (ssAlt in Shift) then
        repeat
          if ssShift in Shift then
          begin
            Dec(NewCurrent.X);
            if NewCurrent.X < FixedCols then
            begin
              NewCurrent.X := ColCount - 1;
              Dec(NewCurrent.Y);
              if NewCurrent.Y < FixedRows then NewCurrent.Y := RowCount - 1;
            end;
            Shift := [];
          end
          else
          begin
            Inc(NewCurrent.X);
            if NewCurrent.X >= ColCount then
            begin
              NewCurrent.X := FixedCols;
              Inc(NewCurrent.Y);
              if NewCurrent.Y >= RowCount then NewCurrent.Y := FixedRows;
            end;
          end;
        until TabStops[NewCurrent.X] or (NewCurrent.X = FCurrent.X);
      VK_F2: EditorMode := True;
    end;
  MaxTopLeft.X := ColCount - 1;
  MaxTopLeft.Y := RowCount - 1;
  MaxTopLeft := CalcMaxTopLeft(MaxTopLeft, DrawInfo);
  Restrict(NewTopLeft, FixedCols, FixedRows, MaxTopLeft.X, MaxTopLeft.Y);
  if (NewTopLeft.X <> LeftCol) or (NewTopLeft.Y <> TopRow) then
    MoveTopLeft(NewTopLeft.X, NewTopLeft.Y);
  Restrict(NewCurrent, FixedCols, FixedRows, ColCount - 1, RowCount - 1);
  if (NewCurrent.X <> Col) or (NewCurrent.Y <> Row) then
    FocusCell(NewCurrent.X, NewCurrent.Y, not (ssShift in Shift)); 
  if NeedsInvalidating then Invalidate;
end;

procedure TCustomGrid.KeyPress(var Key: Char);
begin
  inherited KeyPress(Key);
  if not (goAlwaysShowEditor in Options) and (Key = #13) then
  begin
    if FEditorMode then
      HideEditor else
      ShowEditor;
    Key := #0;
  end;
end;

procedure TCustomGrid.MouseDown(Button: TMouseButton; Shift: TShiftState;
  X, Y: Integer);
var
  CellHit: TGridCoord;
  DrawInfo: TGridDrawInfo;
  MoveDrawn: Boolean;
begin
  MoveDrawn := False;
  HideEdit;
  if not (csDesigning in ComponentState) and
    (CanFocus or (GetParentForm(Self) = nil)) then
  begin
    SetFocus;
    if not IsActiveControl then
    begin
      MouseCapture := False;
      Exit;
    end;
  end;
  if (Button = mbLeft) and (ssDouble in Shift) then
    DblClick
  else if Button = mbLeft then
  begin
    CalcDrawInfo(DrawInfo);
    { Check grid sizing }
    CalcSizingState(X, Y, FGridState, FSizingIndex, FSizingPos, FSizingOfs,
      DrawInfo);
    if FGridState <> gsNormal then
    begin
      if UseRightToLeftAlignment then
        FSizingPos := ClientWidth - FSizingPos;
      DrawSizingLine(DrawInfo);
      Exit;
    end;
    CellHit := CalcCoordFromPoint(X, Y, DrawInfo);
    if (CellHit.X >= FixedCols) and (CellHit.Y >= FixedRows) then
    begin
      if goEditing in Options then
      begin
        if (CellHit.X = FCurrent.X) and (CellHit.Y = FCurrent.Y) then
          ShowEditor
        else
        begin
          MoveCurrent(CellHit.X, CellHit.Y, True, True);
          UpdateEdit;
        end;
        Click;
      end
      else
      begin
        FGridState := gsSelecting;
        SetTimer(Handle, 1, 60, nil);
        if ssShift in Shift then
          MoveAnchor(CellHit)
        else
          MoveCurrent(CellHit.X, CellHit.Y, True, True);
      end;
    end
    else if (goRowMoving in Options) and (CellHit.X >= 0) and
      (CellHit.X < FixedCols) and (CellHit.Y >= FixedRows) then
    begin
      FMoveIndex := CellHit.Y;
      FMovePos := FMoveIndex;
      if BeginRowDrag(FMoveIndex, FMovePos, Point(X,Y)) then
      begin
        FGridState := gsRowMoving;
        Update;
        DrawMove;
        MoveDrawn := True;
        SetTimer(Handle, 1, 60, nil);
      end;
    end
    else if (goColMoving in Options) and (CellHit.Y >= 0) and
      (CellHit.Y < FixedRows) and (CellHit.X >= FixedCols) then
    begin
      FMoveIndex := CellHit.X;
      FMovePos := FMoveIndex;
      if BeginColumnDrag(FMoveIndex, FMovePos, Point(X,Y)) then
      begin
        FGridState := gsColMoving;
        Update;
        DrawMove;
        MoveDrawn := True;
        SetTimer(Handle, 1, 60, nil);
      end;
    end;
  end;
  try
    inherited MouseDown(Button, Shift, X, Y);
  except
    if MoveDrawn then DrawMove;
  end;
end;

procedure TCustomGrid.MouseMove(Shift: TShiftState; X, Y: Integer);
var
  DrawInfo: TGridDrawInfo;
  CellHit: TGridCoord;
begin
  CalcDrawInfo(DrawInfo);
  case FGridState of
    gsSelecting, gsColMoving, gsRowMoving:
      begin
        CellHit := CalcCoordFromPoint(X, Y, DrawInfo);
        if (CellHit.X >= FixedCols) and (CellHit.Y >= FixedRows) and
          (CellHit.X <= DrawInfo.Horz.LastFullVisibleCell+1) and
          (CellHit.Y <= DrawInfo.Vert.LastFullVisibleCell+1) then
          case FGridState of
            gsSelecting:
              if ((CellHit.X <> FAnchor.X) or (CellHit.Y <> FAnchor.Y)) then
                MoveAnchor(CellHit);
            gsColMoving:
              MoveAndScroll(X, CellHit.X, DrawInfo, DrawInfo.Horz, SB_HORZ, Point(X,Y));
            gsRowMoving:
              MoveAndScroll(Y, CellHit.Y, DrawInfo, DrawInfo.Vert, SB_VERT, Point(X,Y));
          end;
      end;
    gsRowSizing, gsColSizing:
      begin
        DrawSizingLine(DrawInfo); { XOR it out }
        if FGridState = gsRowSizing then
          FSizingPos := Y + FSizingOfs else
          FSizingPos := X + FSizingOfs;
        DrawSizingLine(DrawInfo); { XOR it back in }
      end;
  end;
  inherited MouseMove(Shift, X, Y);
end;

procedure TCustomGrid.MouseUp(Button: TMouseButton; Shift: TShiftState;
  X, Y: Integer);
var
  DrawInfo: TGridDrawInfo;
  NewSize: Integer;

  function ResizeLine(const AxisInfo: TGridAxisDrawInfo): Integer;
  var
    I: Integer;
  begin
    with AxisInfo do
    begin
      Result := FixedBoundary;
      for I := FirstGridCell to FSizingIndex - 1 do
        Inc(Result, GetExtent(I) + EffectiveLineWidth);
      Result := FSizingPos - Result;
    end;
  end;

begin
  try
    case FGridState of
      gsSelecting:
        begin
          MouseMove(Shift, X, Y);
          KillTimer(Handle, 1);
          UpdateEdit;
          Click;
        end;
      gsRowSizing, gsColSizing:
        begin
          CalcDrawInfo(DrawInfo);
          DrawSizingLine(DrawInfo);
          if UseRightToLeftAlignment then
            FSizingPos := ClientWidth - FSizingPos;
          if FGridState = gsColSizing then
          begin
            NewSize := ResizeLine(DrawInfo.Horz);
            if NewSize > 1 then
            begin
              ColWidths[FSizingIndex] := NewSize;
              UpdateDesigner;
            end;
          end
          else
          begin
            NewSize := ResizeLine(DrawInfo.Vert);
            if NewSize > 1 then
            begin
              RowHeights[FSizingIndex] := NewSize;
              UpdateDesigner;
            end;
          end;
        end;
      gsColMoving:
        begin
          DrawMove;
          KillTimer(Handle, 1);
          if EndColumnDrag(FMoveIndex, FMovePos, Point(X,Y))
            and (FMoveIndex <> FMovePos) then
          begin
            MoveColumn(FMoveIndex, FMovePos);
            UpdateDesigner;
          end;
          UpdateEdit;
        end;
      gsRowMoving:
        begin
          DrawMove;
          KillTimer(Handle, 1);
          if EndRowDrag(FMoveIndex, FMovePos, Point(X,Y))
            and (FMoveIndex <> FMovePos) then
          begin
            MoveRow(FMoveIndex, FMovePos);
            UpdateDesigner;
          end;
          UpdateEdit;
        end;
    else
      UpdateEdit;
    end;
    inherited MouseUp(Button, Shift, X, Y);
  finally
    FGridState := gsNormal;
  end;
end;

procedure TCustomGrid.MoveAndScroll(Mouse, CellHit: Integer;
  var DrawInfo: TGridDrawInfo; var Axis: TGridAxisDrawInfo;
  ScrollBar: Integer; const MousePt: TPoint);
begin
  if UseRightToLeftAlignment and (ScrollBar = SB_HORZ) then
    Mouse := ClientWidth - Mouse;
  if (CellHit <> FMovePos) and
    not((FMovePos = Axis.FixedCellCount) and (Mouse < Axis.FixedBoundary)) and
    not((FMovePos = Axis.GridCellCount-1) and (Mouse > Axis.GridBoundary)) then
  begin
    DrawMove;   // hide the drag line
    if (Mouse < Axis.FixedBoundary) then
    begin
      if (FMovePos > Axis.FixedCellCount) then
      begin
        ModifyScrollbar(ScrollBar, SB_LINEUP, 0, False);
        Update;
        CalcDrawInfo(DrawInfo);    // this changes contents of Axis var
      end;
      CellHit := Axis.FirstGridCell;
    end
    else if (Mouse >= Axis.FullVisBoundary) then
    begin
      if (FMovePos = Axis.LastFullVisibleCell) and
        (FMovePos < Axis.GridCellCount -1) then
      begin
        ModifyScrollBar(Scrollbar, SB_LINEDOWN, 0, False);
        Update;
        CalcDrawInfo(DrawInfo);    // this changes contents of Axis var
      end;
      CellHit := Axis.LastFullVisibleCell;
    end
    else if CellHit < 0 then CellHit := FMovePos;
    if ((FGridState = gsColMoving) and CheckColumnDrag(FMoveIndex, CellHit, MousePt))
      or ((FGridState = gsRowMoving) and CheckRowDrag(FMoveIndex, CellHit, MousePt)) then
      FMovePos := CellHit;
    DrawMove;
  end;
end;

function TCustomGrid.GetColWidths(Index: Longint): Integer;
begin
  if (FColWidths = nil) or (Index >= ColCount) then
    Result := DefaultColWidth
  else
    Result := PIntArray(FColWidths)^[Index + 1];
end;

function TCustomGrid.GetRowHeights(Index: Longint): Integer;
begin
  if (FRowHeights = nil) or (Index >= RowCount) then
    Result := DefaultRowHeight
  else
    Result := PIntArray(FRowHeights)^[Index + 1];
end;

function TCustomGrid.GetGridWidth: Integer;
var
  DrawInfo: TGridDrawInfo;
begin
  CalcDrawInfo(DrawInfo);
  Result := DrawInfo.Horz.GridBoundary;
end;

function TCustomGrid.GetGridHeight: Integer;
var
  DrawInfo: TGridDrawInfo;
begin
  CalcDrawInfo(DrawInfo);
  Result := DrawInfo.Vert.GridBoundary;
end;

function TCustomGrid.GetSelection: TGridRect;
begin
  Result := GridRect(FCurrent, FAnchor);
end;

function TCustomGrid.GetTabStops(Index: Longint): Boolean;
begin
  if FTabStops = nil then Result := True
  else Result := Boolean(PIntArray(FTabStops)^[Index + 1]);
end;

function TCustomGrid.GetVisibleColCount: Integer;
var
  DrawInfo: TGridDrawInfo;
begin
  CalcDrawInfo(DrawInfo);
  Result := DrawInfo.Horz.LastFullVisibleCell - LeftCol + 1;
end;

function TCustomGrid.GetVisibleRowCount: Integer;
var
  DrawInfo: TGridDrawInfo;
begin
  CalcDrawInfo(DrawInfo);
  Result := DrawInfo.Vert.LastFullVisibleCell - TopRow + 1;
end;

procedure TCustomGrid.SetBorderStyle(Value: TBorderStyle);
begin
  if FBorderStyle <> Value then
  begin
    FBorderStyle := Value;
    RecreateWnd;
  end;
end;

procedure TCustomGrid.SetCol(Value: Longint);
begin
  if Col <> Value then FocusCell(Value, Row, True);
end;

procedure TCustomGrid.SetColCount(Value: Longint);
begin
  if FColCount <> Value then
  begin
    if Value < 1 then Value := 1;
    if Value <= FixedCols then FixedCols := Value - 1;
    ChangeSize(Value, RowCount);
    if goRowSelect in Options then
    begin
      FAnchor.X := ColCount - 1;
      Invalidate;
    end;
  end;
end;

procedure TCustomGrid.SetColWidths(Index: Longint; Value: Integer);
begin
  if FColWidths = nil then
    UpdateExtents(FColWidths, ColCount, DefaultColWidth);
  if Index >= ColCount then InvalidOp(SIndexOutOfRange);
  if Value <> PIntArray(FColWidths)^[Index + 1] then
  begin
    ResizeCol(Index, PIntArray(FColWidths)^[Index + 1], Value);
    PIntArray(FColWidths)^[Index + 1] := Value;
    ColWidthsChanged;
  end;
end;

procedure TCustomGrid.SetDefaultColWidth(Value: Integer);
begin
  if FColWidths <> nil then UpdateExtents(FColWidths, 0, 0);
  FDefaultColWidth := Value;
  ColWidthsChanged;
  InvalidateGrid;
end;

procedure TCustomGrid.SetDefaultRowHeight(Value: Integer);
begin
  if FRowHeights <> nil then UpdateExtents(FRowHeights, 0, 0);
  FDefaultRowHeight := Value;
  RowHeightsChanged;
  InvalidateGrid;
end;

procedure TCustomGrid.SetFixedColor(Value: TColor);
begin
  if FFixedColor <> Value then
  begin
    FFixedColor := Value;
    InvalidateGrid;
  end;
end;

procedure TCustomGrid.SetFixedCols(Value: Integer);
begin
  if FFixedCols <> Value then
  begin
    if Value < 0 then InvalidOp(SIndexOutOfRange);
    if Value >= ColCount then InvalidOp(SFixedColTooBig);
    FFixedCols := Value;
    Initialize;
    InvalidateGrid;
  end;
end;

procedure TCustomGrid.SetFixedRows(Value: Integer);
begin
  if FFixedRows <> Value then
  begin
    if Value < 0 then InvalidOp(SIndexOutOfRange);
    if Value >= RowCount then InvalidOp(SFixedRowTooBig);
    FFixedRows := Value;
    Initialize;
    InvalidateGrid;
  end;
end;

procedure TCustomGrid.SetEditorMode(Value: Boolean);
begin
  if not Value then
    HideEditor
  else
  begin
    ShowEditor;
    if FInplaceEdit <> nil then FInplaceEdit.Deselect;
  end;
end;

procedure TCustomGrid.SetGridLineWidth(Value: Integer);
begin
  if FGridLineWidth <> Value then
  begin
    FGridLineWidth := Value;
    InvalidateGrid;
  end;
end;

procedure TCustomGrid.SetLeftCol(Value: Longint);
begin
  if FTopLeft.X <> Value then MoveTopLeft(Value, TopRow);
end;

procedure TCustomGrid.SetOptions(Value: TGridOptions);
begin
  if FOptions <> Value then
  begin
    if goRowSelect in Value then
      Exclude(Value, goAlwaysShowEditor);
    FOptions := Value;
    if not FEditorMode then
      if goAlwaysShowEditor in Value then
        ShowEditor else
        HideEditor;
    if goRowSelect in Value then MoveCurrent(Col, Row,  True, False);
    InvalidateGrid;
  end;
end;

procedure TCustomGrid.SetRow(Value: Longint);
begin
  if Row <> Value then FocusCell(Col, Value, True);
end;

procedure TCustomGrid.SetRowCount(Value: Longint);
begin
  if FRowCount <> Value then
  begin
    if Value < 1 then Value := 1;
    if Value <= FixedRows then FixedRows := Value - 1;
    ChangeSize(ColCount, Value);
  end;
end;

procedure TCustomGrid.SetRowHeights(Index: Longint; Value: Integer);
begin
  if FRowHeights = nil then
    UpdateExtents(FRowHeights, RowCount, DefaultRowHeight);
  if Index >= RowCount then InvalidOp(SIndexOutOfRange);
  if Value <> PIntArray(FRowHeights)^[Index + 1] then
  begin
    ResizeRow(Index, PIntArray(FRowHeights)^[Index + 1], Value);
    PIntArray(FRowHeights)^[Index + 1] := Value;
    RowHeightsChanged;
  end;
end;

procedure TCustomGrid.SetScrollBars(Value: TScrollStyle);
begin
  if FScrollBars <> Value then
  begin
    FScrollBars := Value;
    RecreateWnd;
  end;
end;

procedure TCustomGrid.SetSelection(Value: TGridRect);
var
  OldSel: TGridRect;
begin
  OldSel := Selection;
  FAnchor := Value.TopLeft;
  FCurrent := Value.BottomRight;
  SelectionMoved(OldSel);
end;

procedure TCustomGrid.SetTabStops(Index: Longint; Value: Boolean);
begin
  if FTabStops = nil then
    UpdateExtents(FTabStops, ColCount, Integer(True));
  if Index >= ColCount then InvalidOp(SIndexOutOfRange);
  PIntArray(FTabStops)^[Index + 1] := Integer(Value);
end;

procedure TCustomGrid.SetTopRow(Value: Longint);
begin
  if FTopLeft.Y <> Value then MoveTopLeft(LeftCol, Value);
end;

procedure TCustomGrid.HideEdit;
begin
  if FInplaceEdit <> nil then
    try
      UpdateText;
    finally
      FInplaceCol := -1;
      FInplaceRow := -1;
      FInplaceEdit.Hide;
    end;
end;

procedure TCustomGrid.UpdateEdit;

  procedure UpdateEditor;
  begin
    FInplaceCol := Col;
    FInplaceRow := Row;
    FInplaceEdit.UpdateContents;
    if FInplaceEdit.MaxLength = -1 then FCanEditModify := False
    else FCanEditModify := True;
    FInplaceEdit.SelectAll;
  end;

begin
  if CanEditShow then
  begin
    if FInplaceEdit = nil then
    begin

    end
    else
    begin
      if (Col <> FInplaceCol) or (Row <> FInplaceRow) then
      begin
        HideEdit;
        UpdateEditor;
      end;
    end;
    if CanEditShow then FInplaceEdit.Move(CellRect(Col, Row));
  end;
end;

procedure TCustomGrid.UpdateText;
begin
  if (FInplaceCol <> -1) and (FInplaceRow <> -1) then
    SetEditText(FInplaceCol, FInplaceRow, FInplaceEdit.Text);
end;

procedure TCustomGrid.WMChar(var Msg: TWMChar);
begin
  if (goEditing in Options) and (Char(Msg.CharCode) in [^H, #32..#255]) then
    ShowEditorChar(Char(Msg.CharCode))
  else
    inherited;
end;

procedure TCustomGrid.WMCommand(var Message: TWMCommand);
begin
  with Message do
  begin
    if (FInplaceEdit <> nil) and (Ctl = FInplaceEdit.Handle) then
      case NotifyCode of
        EN_CHANGE: UpdateText;
      end;
  end;
end;

procedure TCustomGrid.WMGetDlgCode(var Msg: TWMGetDlgCode);
begin
  Msg.Result := DLGC_WANTARROWS;
  if goRowSelect in Options then Exit;
  if goTabs in Options then Msg.Result := Msg.Result or DLGC_WANTTAB;
  if goEditing in Options then Msg.Result := Msg.Result or DLGC_WANTCHARS;
end;

procedure TCustomGrid.WMKillFocus(var Msg: TWMKillFocus);
begin
  inherited;
  InvalidateRect(Selection);
  if (FInplaceEdit <> nil) and (Msg.FocusedWnd <> FInplaceEdit.Handle) then
    HideEdit;
end;

procedure TCustomGrid.WMLButtonDown(var Message: TMessage);
begin
  inherited;
  if FInplaceEdit <> nil then FInplaceEdit.FClickTime := GetMessageTime;
end;

procedure TCustomGrid.WMNCHitTest(var Msg: TWMNCHitTest);
begin
  DefaultHandler(Msg);
  FHitTest := ScreenToClient(SmallPointToPoint(Msg.Pos));
end;

procedure TCustomGrid.WMSetCursor(var Msg: TWMSetCursor);
var
  DrawInfo: TGridDrawInfo;
  State: TGridState;
  Index: Longint;
  Pos, Ofs: Integer;
  Cur: HCURSOR;
begin
  Cur := 0;
  with Msg do
  begin
    if HitTest = HTCLIENT then
    begin
      if FGridState = gsNormal then
      begin
        CalcDrawInfo(DrawInfo);
        CalcSizingState(FHitTest.X, FHitTest.Y, State, Index, Pos, Ofs,
          DrawInfo);
      end else State := FGridState;
      if State = gsRowSizing then
        Cur := Screen.Cursors[crVSplit]
      else if State = gsColSizing then
        Cur := Screen.Cursors[crHSplit]
    end;
  end;
  if Cur <> 0 then SetCursor(Cur)
  else inherited;
end;

procedure TCustomGrid.WMSetFocus(var Msg: TWMSetFocus);
begin
  inherited;
  if (FInplaceEdit = nil) or (Msg.FocusedWnd <> FInplaceEdit.Handle) then
  begin
    InvalidateRect(Selection);
    UpdateEdit;
  end;
end;

procedure TCustomGrid.WMSize(var Msg: TWMSize);
begin
  inherited;
  UpdateScrollRange;
  if UseRightToLeftAlignment then Invalidate;
end;

procedure TCustomGrid.WMVScroll(var Msg: TWMVScroll);
begin
  ModifyScrollBar(SB_VERT, Msg.ScrollCode, Msg.Pos, True);
end;

procedure TCustomGrid.WMHScroll(var Msg: TWMHScroll);
begin
  ModifyScrollBar(SB_HORZ, Msg.ScrollCode, Msg.Pos, True);
end;

procedure TCustomGrid.CancelMode;
var
  DrawInfo: TGridDrawInfo;
begin
  try
    case FGridState of
      gsSelecting:
        KillTimer(Handle, 1);
      gsRowSizing, gsColSizing:
        begin
          CalcDrawInfo(DrawInfo);
          DrawSizingLine(DrawInfo);
        end;
      gsColMoving, gsRowMoving:
        begin
          DrawMove;
          KillTimer(Handle, 1);
        end;
    end;
  finally
    FGridState := gsNormal;
  end;
end;

procedure TCustomGrid.WMCancelMode(var Msg: TWMCancelMode);
begin
  inherited;
  CancelMode;
end;

procedure TCustomGrid.CMCancelMode(var Msg: TMessage);
begin
  if Assigned(FInplaceEdit) then FInplaceEdit.WndProc(Msg);
  inherited;
  CancelMode;
end;

procedure TCustomGrid.CMFontChanged(var Message: TMessage);
begin
  if FInplaceEdit <> nil then FInplaceEdit.Font := Font;
  inherited;
end;

procedure TCustomGrid.CMCtl3DChanged(var Message: TMessage);
begin
  inherited;
  RecreateWnd;
end;

procedure TCustomGrid.CMDesignHitTest(var Msg: TCMDesignHitTest);
begin
  Msg.Result := Longint(BOOL(Sizing(Msg.Pos.X, Msg.Pos.Y)));
end;

procedure TCustomGrid.CMWantSpecialKey(var Msg: TCMWantSpecialKey);
begin
  inherited;
  if (goEditing in Options) and (Char(Msg.CharCode) = #13) then Msg.Result := 1;
end;

procedure TCustomGrid.TimedScroll(Direction: TGridScrollDirection);
var
  MaxAnchor, NewAnchor: TGridCoord;
begin
  NewAnchor := FAnchor;
  MaxAnchor.X := ColCount - 1;
  MaxAnchor.Y := RowCount - 1;
  if (sdLeft in Direction) and (FAnchor.X > FixedCols) then Dec(NewAnchor.X);
  if (sdRight in Direction) and (FAnchor.X < MaxAnchor.X) then Inc(NewAnchor.X);
  if (sdUp in Direction) and (FAnchor.Y > FixedRows) then Dec(NewAnchor.Y);
  if (sdDown in Direction) and (FAnchor.Y < MaxAnchor.Y) then Inc(NewAnchor.Y);
  if (FAnchor.X <> NewAnchor.X) or (FAnchor.Y <> NewAnchor.Y) then
    MoveAnchor(NewAnchor);
end;

procedure TCustomGrid.WMTimer(var Msg: TWMTimer);
var
  Point: TPoint;
  DrawInfo: TGridDrawInfo;
  ScrollDirection: TGridScrollDirection;
  CellHit: TGridCoord;
  LeftSide: Integer;
  RightSide: Integer;
begin
  if not (FGridState in [gsSelecting, gsRowMoving, gsColMoving]) then Exit;
  GetCursorPos(Point);
  Point := ScreenToClient(Point);
  CalcDrawInfo(DrawInfo);
  ScrollDirection := [];
  with DrawInfo do
  begin
    CellHit := CalcCoordFromPoint(Point.X, Point.Y, DrawInfo);
    case FGridState of
      gsColMoving:
        MoveAndScroll(Point.X, CellHit.X, DrawInfo, Horz, SB_HORZ, Point);
      gsRowMoving:
        MoveAndScroll(Point.Y, CellHit.Y, DrawInfo, Vert, SB_VERT, Point);
      gsSelecting:
      begin
        if not UseRightToLeftAlignment then
        begin
          if Point.X < Horz.FixedBoundary then Include(ScrollDirection, sdLeft)
          else if Point.X > Horz.FullVisBoundary then Include(ScrollDirection, sdRight);
        end
        else
        begin
          LeftSide := ClientWidth - Horz.FullVisBoundary;
          RightSide := ClientWidth - Horz.FixedBoundary;
          if Point.X < LeftSide then Include(ScrollDirection, sdRight)
          else if Point.X > RightSide then Include(ScrollDirection, sdLeft);
        end;
        if Point.Y < Vert.FixedBoundary then Include(ScrollDirection, sdUp)
        else if Point.Y > Vert.FullVisBoundary then Include(ScrollDirection, sdDown);
        if ScrollDirection <> [] then  TimedScroll(ScrollDirection);
      end;
    end;
  end;
end;

procedure TCustomGrid.ColWidthsChanged;
begin
  UpdateScrollRange;
  UpdateEdit;
end;

procedure TCustomGrid.RowHeightsChanged;
begin
  UpdateScrollRange;
  UpdateEdit;
end;

procedure TCustomGrid.DeleteColumn(ACol: Longint);
begin
  MoveColumn(ACol, ColCount-1);
  ColCount := ColCount - 1;
end;

procedure TCustomGrid.DeleteRow(ARow: Longint);
begin
  MoveRow(ARow, RowCount - 1);
  RowCount := RowCount - 1;
end;

procedure TCustomGrid.UpdateDesigner;
var
  ParentForm: TCustomForm;
begin
  if (csDesigning in ComponentState) and HandleAllocated and
    not (csUpdating in ComponentState) then
  begin
    ParentForm := GetParentForm(Self);
    if Assigned(ParentForm) and Assigned(ParentForm.Designer) then
      ParentForm.Designer.Modified;
  end;
end;

function TCustomGrid.DoMouseWheelDown(Shift: TShiftState; MousePos: TPoint): Boolean;
begin
  Result := inherited DoMouseWheelDown(Shift, MousePos);
  if not Result then
  begin
    if Row < RowCount - 1 then Row := Row + 1;
    Result := True;
  end;
end;

function TCustomGrid.DoMouseWheelUp(Shift: TShiftState; MousePos: TPoint): Boolean;
begin
  Result := inherited DoMouseWheelUp(Shift, MousePos);
  if not Result then
  begin
    if Row > FixedRows then Row := Row - 1;
    Result := True;
  end;
end;

function TCustomGrid.CheckColumnDrag(var Origin,
  Destination: Integer; const MousePt: TPoint): Boolean;
begin
  Result := True;
end;

function TCustomGrid.CheckRowDrag(var Origin,
  Destination: Integer; const MousePt: TPoint): Boolean;
begin
  Result := True;
end;

function TCustomGrid.BeginColumnDrag(var Origin, Destination: Integer; const MousePt: TPoint): Boolean;
begin
  Result := True;
end;

function TCustomGrid.BeginRowDrag(var Origin, Destination: Integer; const MousePt: TPoint): Boolean;
begin
  Result := True;
end;

function TCustomGrid.EndColumnDrag(var Origin, Destination: Integer; const MousePt: TPoint): Boolean;
begin
  Result := True;
end;

function TCustomGrid.EndRowDrag(var Origin, Destination: Integer; const MousePt: TPoint): Boolean;
begin
  Result := True;
end;

procedure TCustomGrid.CMShowingChanged(var Message: TMessage);
begin
  inherited;
  if Showing then UpdateScrollRange;
end;

{ TDrawGrid }

function TDrawGrid.CellRect(ACol, ARow: Longint): TRect;
begin
  Result := inherited CellRect(ACol, ARow);
end;

procedure TDrawGrid.MouseToCell(X, Y: Integer; var ACol, ARow: Longint);
var
  Coord: TGridCoord;
begin
  Coord := MouseCoord(X, Y);
  ACol := Coord.X;
  ARow := Coord.Y;
end;

procedure TDrawGrid.ColumnMoved(FromIndex, ToIndex: Longint);
begin
  if Assigned(FOnColumnMoved) then FOnColumnMoved(Self, FromIndex, ToIndex);
end;

function TDrawGrid.GetEditMask(ACol, ARow: Longint): string;
begin
  Result := '';
  if Assigned(FOnGetEditMask) then FOnGetEditMask(Self, ACol, ARow, Result);
end;

function TDrawGrid.GetEditText(ACol, ARow: Longint): string;
begin
  Result := '';
  if Assigned(FOnGetEditText) then FOnGetEditText(Self, ACol, ARow, Result);
end;

procedure TDrawGrid.RowMoved(FromIndex, ToIndex: Longint);
begin
  if Assigned(FOnRowMoved) then FOnRowMoved(Self, FromIndex, ToIndex);
end;

function TDrawGrid.SelectCell(ACol, ARow: Longint): Boolean;
begin
  Result := True;
  if Assigned(FOnSelectCell) then FOnSelectCell(Self, ACol, ARow, Result);
end;

procedure TDrawGrid.SetEditText(ACol, ARow: Longint; const Value: string);
begin
  if Assigned(FOnSetEditText) then FOnSetEditText(Self, ACol, ARow, Value);
end;

procedure TDrawGrid.DrawCell(ACol, ARow: Longint; ARect: TRect;
  AState: TGridDrawState);
var
  Hold: Integer;
begin
  if Assigned(FOnDrawCell) then
  begin
    if UseRightToLeftAlignment then
    begin
      ARect.Left := ClientWidth - ARect.Left;
      ARect.Right := ClientWidth - ARect.Right;
      Hold := ARect.Left;
      ARect.Left := ARect.Right;
      ARect.Right := Hold;
      ChangeGridOrientation(False);
    end;
    FOnDrawCell(Self, ACol, ARow, ARect, AState);
    if UseRightToLeftAlignment then ChangeGridOrientation(True); 
  end;
end;

procedure TDrawGrid.TopLeftChanged;
begin
  inherited TopLeftChanged;
  if Assigned(FOnTopLeftChanged) then FOnTopLeftChanged(Self);
end;

{ StrItem management for TStringSparseList }

type
  PStrItem = ^TStrItem;
  TStrItem = record
    FObject: TObject;
    FString: string;
  end;

function NewStrItem(const AString: string; AObject: TObject): PStrItem;
begin
  New(Result);
  Result^.FObject := AObject;
  Result^.FString := AString;
end;

procedure DisposeStrItem(P: PStrItem);
begin
  Dispose(P);
end;

{ Sparse array classes for TStringGrid }

type

  PPointer = ^Pointer;

{ Exception classes }

  EStringSparseListError = class(Exception);

{ TSparsePointerArray class}

{ Used by TSparseList.  Based on Sparse1Array, but has Pointer elements
  and Integer index, just like TPointerList/TList, and less indirection }

  { Apply function for the applicator:
        TheIndex        Index of item in array
        TheItem         Value of item (i.e pointer element) in section
        Returns: 0 if success, else error code. }
  TSPAApply = function(TheIndex: Integer; TheItem: Pointer): Integer;

  TSecDir = array[0..4095] of Pointer;  { Enough for up to 12 bits of sec }
  PSecDir = ^TSecDir;
  TSPAQuantum = (SPASmall, SPALarge);   { Section size }

  TSparsePointerArray = class(TObject)
  private
    secDir: PSecDir;
    slotsInDir: Word;
    indexMask, secShift: Word;
    FHighBound: Integer;
    FSectionSize: Word;
    cachedIndex: Integer;
    cachedPointer: Pointer;
    { Return item[i], nil if slot outside defined section. }
    function  GetAt(Index: Integer): Pointer;
    { Return address of item[i], creating slot if necessary. }
    function  MakeAt(Index: Integer): PPointer;
    { Store item at item[i], creating slot if necessary. }
    procedure PutAt(Index: Integer; Item: Pointer);
  public
    constructor Create(Quantum: TSPAQuantum);
    destructor  Destroy; override;

    { Traverse SPA, calling apply function for each defined non-nil
      item.  The traversal terminates if the apply function returns
      a value other than 0. }
    { NOTE: must be static method so that we can take its address in
      TSparseList.ForAll }
    function  ForAll(ApplyFunction: Pointer {TSPAApply}): Integer;

    { Ratchet down HighBound after a deletion }
    procedure ResetHighBound;

    property HighBound: Integer read FHighBound;
    property SectionSize: Word read FSectionSize;
    property Items[Index: Integer]: Pointer read GetAt write PutAt; default;
  end;

{ TSparseList class }

  TSparseList = class(TObject)
  private
    FList: TSparsePointerArray;
    FCount: Integer;    { 1 + HighBound, adjusted for Insert/Delete }
    FQuantum: TSPAQuantum;
    procedure NewList(Quantum: TSPAQuantum);
  protected
    function  Get(Index: Integer): Pointer;
    procedure Put(Index: Integer; Item: Pointer);
  public
    constructor Create(Quantum: TSPAQuantum);
    destructor  Destroy; override;
    procedure Clear;
    procedure Delete(Index: Integer);
    procedure Exchange(Index1, Index2: Integer);
    function ForAll(ApplyFunction: Pointer {TSPAApply}): Integer;
    procedure Insert(Index: Integer; Item: Pointer);
    procedure Move(CurIndex, NewIndex: Integer);
    property Count: Integer read FCount;
    property Items[Index: Integer]: Pointer read Get write Put; default;
  end;

{ TStringSparseList class }

  TStringSparseList = class(TStrings)
  private
    FList: TSparseList;                 { of StrItems }
    FOnChange: TNotifyEvent;
  protected
    function  Get(Index: Integer): String; override;
    function  GetCount: Integer; override;
    function  GetObject(Index: Integer): TObject; override;
    procedure Put(Index: Integer; const S: String); override;
    procedure PutObject(Index: Integer; AObject: TObject); override;
    procedure Changed;
  public
    constructor Create(Quantum: TSPAQuantum);
    destructor  Destroy; override;
    procedure ReadData(Reader: TReader);
    procedure WriteData(Writer: TWriter);
    procedure DefineProperties(Filer: TFiler); override;
    procedure Delete(Index: Integer); override;
    procedure Exchange(Index1, Index2: Integer); override;
    procedure Insert(Index: Integer; const S: String); override;
    procedure Clear; override;
    property List: TSparseList read FList;
    property OnChange: TNotifyEvent read FOnChange write FOnChange;
  end;

{ TSparsePointerArray }

const
  SPAIndexMask: array[TSPAQuantum] of Byte = (15, 255);
  SPASecShift: array[TSPAQuantum] of Byte = (4, 8);

{ Expand Section Directory to cover at least `newSlots' slots. Returns: Possibly
  updated pointer to the Section Directory. }
function  ExpandDir(secDir: PSecDir; var slotsInDir: Word;
  newSlots: Word): PSecDir;
begin
  Result := secDir;
  ReallocMem(Result, newSlots * SizeOf(Pointer));
  FillChar(Result^[slotsInDir], (newSlots - slotsInDir) * SizeOf(Pointer), 0);
  slotsInDir := newSlots;
end;

{ Allocate a section and set all its items to nil. Returns: Pointer to start of
  section. }
function  MakeSec(SecIndex: Integer; SectionSize: Word): Pointer;
var
  SecP: Pointer;
  Size: Word;
begin
  Size := SectionSize * SizeOf(Pointer);
  GetMem(secP, size);
  FillChar(secP^, size, 0);
  MakeSec := SecP
end;

constructor TSparsePointerArray.Create(Quantum: TSPAQuantum);
begin
  SecDir := nil;
  SlotsInDir := 0;
  FHighBound := -1;
  FSectionSize := Word(SPAIndexMask[Quantum]) + 1;
  IndexMask := Word(SPAIndexMask[Quantum]);
  SecShift := Word(SPASecShift[Quantum]);
  CachedIndex := -1
end;

destructor TSparsePointerArray.Destroy;
var
  i:  Integer;
  size: Word;
begin
  { Scan section directory and free each section that exists. }
  i := 0;
  size := FSectionSize * SizeOf(Pointer);
  while i < slotsInDir do begin
    if secDir^[i] <> nil then
      FreeMem(secDir^[i], size);
    Inc(i)
  end;

  { Free section directory. }
  if secDir <> nil then
    FreeMem(secDir, slotsInDir * SizeOf(Pointer));
end;

function  TSparsePointerArray.GetAt(Index: Integer): Pointer;
var
  byteP: PChar;
  secIndex: Cardinal;
begin
  { Index into Section Directory using high order part of
    index.  Get pointer to Section. If not null, index into
    Section using low order part of index. }
  if Index = cachedIndex then
    Result := cachedPointer
  else begin
    secIndex := Index shr secShift;
    if secIndex >= slotsInDir then
      byteP := nil
    else begin
      byteP := secDir^[secIndex];
      if byteP <> nil then begin
        Inc(byteP, (Index and indexMask) * SizeOf(Pointer));
      end
    end;
    if byteP = nil then Result := nil else Result := PPointer(byteP)^;
    cachedIndex := Index;
    cachedPointer := Result
  end
end;

function  TSparsePointerArray.MakeAt(Index: Integer): PPointer;
var
  dirP: PSecDir;
  p: Pointer;
  byteP: PChar;
  secIndex: Word;
begin
  { Expand Section Directory if necessary. }
  secIndex := Index shr secShift;       { Unsigned shift }
  if secIndex >= slotsInDir then
    dirP := expandDir(secDir, slotsInDir, secIndex + 1)
  else
    dirP := secDir;

  { Index into Section Directory using high order part of
    index.  Get pointer to Section. If null, create new
    Section.  Index into Section using low order part of index. }
  secDir := dirP;
  p := dirP^[secIndex];
  if p = nil then begin
    p := makeSec(secIndex, FSectionSize);
    dirP^[secIndex] := p
  end;
  byteP := p;
  Inc(byteP, (Index and indexMask) * SizeOf(Pointer));
  if Index > FHighBound then
    FHighBound := Index;
  Result := PPointer(byteP);
  cachedIndex := -1
end;

procedure TSparsePointerArray.PutAt(Index: Integer; Item: Pointer);
begin
  if (Item <> nil) or (GetAt(Index) <> nil) then
  begin
    MakeAt(Index)^ := Item;
    if Item = nil then
      ResetHighBound
  end
end;

function  TSparsePointerArray.ForAll(ApplyFunction: Pointer {TSPAApply}):
  Integer;
var
  itemP: PChar;                         { Pointer to item in section }
  item: Pointer;
  i, callerBP: Cardinal;
  j, index: Integer;
begin
  { Scan section directory and scan each section that exists,
    calling the apply function for each non-nil item.
    The apply function must be a far local function in the scope of
    the procedure P calling ForAll.  The trick of setting up the stack
    frame (taken from TurboVision's TCollection.ForEach) allows the
    apply function access to P's arguments and local variables and,
    if P is a method, the instance variables and methods of P's class }
  Result := 0;
  i := 0;
  asm
    mov   eax,[ebp]                     { Set up stack frame for local }
    mov   callerBP,eax
  end;
  while (i < slotsInDir) and (Result = 0) do begin
    itemP := secDir^[i];
    if itemP <> nil then begin
      j := 0;
      index := i shl SecShift;
      while (j < FSectionSize) and (Result = 0) do begin
        item := PPointer(itemP)^;
        if item <> nil then
          { ret := ApplyFunction(index, item.Ptr); }
          asm
            mov   eax,index
            mov   edx,item
            push  callerBP
            call  ApplyFunction
            pop   ecx
            mov   @Result,eax
          end;
        Inc(itemP, SizeOf(Pointer));
        Inc(j);
        Inc(index)
      end
    end;
    Inc(i)
  end;
end;

procedure TSparsePointerArray.ResetHighBound;
var
  NewHighBound: Integer;

  function  Detector(TheIndex: Integer; TheItem: Pointer): Integer; far;
  begin
    if TheIndex > FHighBound then
      Result := 1
    else
    begin
      Result := 0;
      if TheItem <> nil then NewHighBound := TheIndex
    end
  end;

begin
  NewHighBound := -1;
  ForAll(@Detector);
  FHighBound := NewHighBound
end;

{ TSparseList }

constructor TSparseList.Create(Quantum: TSPAQuantum);
begin
  NewList(Quantum)
end;

destructor TSparseList.Destroy;
begin
  if FList <> nil then FList.Destroy
end;

procedure TSparseList.Clear;
begin
  FList.Destroy;
  NewList(FQuantum);
  FCount := 0
end;

procedure TSparseList.Delete(Index: Integer);
var
  I: Integer;
begin
  if (Index < 0) or (Index >= FCount) then Exit;
  for I := Index to FCount - 1 do
    FList[I] := FList[I + 1];
  FList[FCount] := nil;
  Dec(FCount);
end;

procedure TSparseList.Exchange(Index1, Index2: Integer);
var
  temp: Pointer;
begin
  temp := Get(Index1);
  Put(Index1, Get(Index2));
  Put(Index2, temp);
end;

{ Jump to TSparsePointerArray.ForAll so that it looks like it was called
  from our caller, so that the BP trick works. }

function TSparseList.ForAll(ApplyFunction: Pointer {TSPAApply}): Integer; assembler;
asm
        MOV     EAX,[EAX].TSparseList.FList
        JMP     TSparsePointerArray.ForAll
end;

function  TSparseList.Get(Index: Integer): Pointer;
begin
  if Index < 0 then TList.Error(SListIndexError, Index);
  Result := FList[Index]
end;

procedure TSparseList.Insert(Index: Integer; Item: Pointer);
var
  i: Integer;
begin
  if Index < 0 then TList.Error(SListIndexError, Index);
  I := FCount;
  while I > Index do
  begin
    FList[i] := FList[i - 1];
    Dec(i)
  end;
  FList[Index] := Item;
  if Index > FCount then FCount := Index;
  Inc(FCount)
end;

procedure TSparseList.Move(CurIndex, NewIndex: Integer);
var
  Item: Pointer;
begin
  if CurIndex <> NewIndex then
  begin
    Item := Get(CurIndex);
    Delete(CurIndex);
    Insert(NewIndex, Item);
  end;
end;

procedure TSparseList.NewList(Quantum: TSPAQuantum);
begin
  FQuantum := Quantum;
  FList := TSparsePointerArray.Create(Quantum)
end;

procedure TSparseList.Put(Index: Integer; Item: Pointer);
begin
  if Index < 0 then TList.Error(SListIndexError, Index);
  FList[Index] := Item;
  FCount := FList.HighBound + 1
end;

{ TStringSparseList }

constructor TStringSparseList.Create(Quantum: TSPAQuantum);
begin
  FList := TSparseList.Create(Quantum)
end;

destructor  TStringSparseList.Destroy;
begin
  if FList <> nil then begin
    Clear;
    FList.Destroy
  end
end;

procedure TStringSparseList.ReadData(Reader: TReader);
var
  i: Integer;
begin
  with Reader do begin
    i := Integer(ReadInteger);
    while i > 0 do begin
      InsertObject(Integer(ReadInteger), ReadString, nil);
      Dec(i)
    end
  end
end;

procedure TStringSparseList.WriteData(Writer: TWriter);
var
  itemCount: Integer;

  function  CountItem(TheIndex: Integer; TheItem: Pointer): Integer; far;
  begin
    Inc(itemCount);
    Result := 0
  end;

  function  StoreItem(TheIndex: Integer; TheItem: Pointer): Integer; far;
  begin
    with Writer do
    begin
      WriteInteger(TheIndex);           { Item index }
      WriteString(PStrItem(TheItem)^.FString);
    end;
    Result := 0
  end;

begin
  with Writer do
  begin
    itemCount := 0;
    FList.ForAll(@CountItem);
    WriteInteger(itemCount);
    FList.ForAll(@StoreItem);
  end
end;

procedure TStringSparseList.DefineProperties(Filer: TFiler);
begin
  Filer.DefineProperty('List', ReadData, WriteData, True);
end;

function  TStringSparseList.Get(Index: Integer): String;
var
  p: PStrItem;
begin
  p := PStrItem(FList[Index]);
  if p = nil then Result := '' else Result := p^.FString
end;

function  TStringSparseList.GetCount: Integer;
begin
  Result := FList.Count
end;

function  TStringSparseList.GetObject(Index: Integer): TObject;
var
  p: PStrItem;
begin
  p := PStrItem(FList[Index]);
  if p = nil then Result := nil else Result := p^.FObject
end;

procedure TStringSparseList.Put(Index: Integer; const S: String);
var
  p: PStrItem;
  obj: TObject;
begin
  p := PStrItem(FList[Index]);
  if p = nil then obj := nil else obj := p^.FObject;
  if (S = '') and (obj = nil) then   { Nothing left to store }
    FList[Index] := nil
  else
    FList[Index] := NewStrItem(S, obj);
  if p <> nil then DisposeStrItem(p);
  Changed
end;

procedure TStringSparseList.PutObject(Index: Integer; AObject: TObject);
var
  p: PStrItem;
begin
  p := PStrItem(FList[Index]);
  if p <> nil then
    p^.FObject := AObject
  else if AObject <> nil then
    FList[Index] := NewStrItem('',AObject);
  Changed
end;

procedure TStringSparseList.Changed;
begin
  if Assigned(FOnChange) then FOnChange(Self)
end;

procedure TStringSparseList.Delete(Index: Integer);
var
  p: PStrItem;
begin
  p := PStrItem(FList[Index]);
  if p <> nil then DisposeStrItem(p);
  FList.Delete(Index);
  Changed
end;

procedure TStringSparseList.Exchange(Index1, Index2: Integer);
begin
  FList.Exchange(Index1, Index2);
end;

procedure TStringSparseList.Insert(Index: Integer; const S: String);
begin
  FList.Insert(Index, NewStrItem(S, nil));
  Changed
end;

procedure TStringSparseList.Clear;

  function  ClearItem(TheIndex: Integer; TheItem: Pointer): Integer; far;
  begin
    DisposeStrItem(PStrItem(TheItem));    { Item guaranteed non-nil }
    Result := 0
  end;

begin
  FList.ForAll(@ClearItem);
  FList.Clear;
  Changed
end;

{ TStringGridStrings }

{ AIndex < 0 is a column (for column -AIndex - 1)
  AIndex > 0 is a row (for row AIndex - 1)
  AIndex = 0 denotes an empty row or column }

constructor TStringGridStrings.Create(AGrid: TStringGrid; AIndex: Longint);
begin
  inherited Create;
  FGrid := AGrid;
  FIndex := AIndex;
end;

procedure TStringGridStrings.Assign(Source: TPersistent);
var
  I, Max: Integer;
begin
  if Source is TStrings then
  begin
    BeginUpdate;
    Max := TStrings(Source).Count - 1;
    if Max >= Count then Max := Count - 1;
    try
      for I := 0 to Max do
      begin
        Put(I, TStrings(Source).Strings[I]);
        PutObject(I, TStrings(Source).Objects[I]);
      end;
    finally
      EndUpdate;
    end;
    Exit;
  end;
  inherited Assign(Source);
end;

procedure TStringGridStrings.CalcXY(Index: Integer; var X, Y: Integer);
begin
  if FIndex = 0 then
  begin
    X := -1; Y := -1;
  end else if FIndex > 0 then
  begin
    X := Index;
    Y := FIndex - 1;
  end else
  begin
    X := -FIndex - 1;
    Y := Index;
  end;
end;

{ Changes the meaning of Add to mean copy to the first empty string }
function TStringGridStrings.Add(const S: string): Integer;
var
  I: Integer;
begin
  for I := 0 to Count - 1 do
    if Strings[I] = '' then
    begin
      if S = '' then
        Strings[I] := ' '
      else
        Strings[I] := S;
      Result := I;
      Exit;
    end;
  Result := -1;
end;

procedure TStringGridStrings.Clear;
var
  SSList: TStringSparseList;
  I: Integer;

  function BlankStr(TheIndex: Integer; TheItem: Pointer): Integer; far;
  begin
    Objects[TheIndex] := nil;
    Strings[TheIndex] := '';
    Result := 0;
  end;

begin
  if FIndex > 0 then
  begin
    SSList := TStringSparseList(TSparseList(FGrid.FData)[FIndex - 1]);
    if SSList <> nil then SSList.List.ForAll(@BlankStr);
  end
  else if FIndex < 0 then
    for I := Count - 1 downto 0 do
    begin
      Objects[I] := nil;
      Strings[I] := '';
    end;
end;

procedure TStringGridStrings.Delete(Index: Integer);
begin
  InvalidOp(sInvalidStringGridOp);
end;

function TStringGridStrings.Get(Index: Integer): string;
var
  X, Y: Integer;
begin
  CalcXY(Index, X, Y);
  if X < 0 then Result := '' else Result := FGrid.Cells[X, Y];
end;

function TStringGridStrings.GetCount: Integer;
begin
  { Count of a row is the column count, and vice versa }
  if FIndex = 0 then Result := 0
  else if FIndex > 0 then Result := Integer(FGrid.ColCount)
  else Result := Integer(FGrid.RowCount);
end;

function TStringGridStrings.GetObject(Index: Integer): TObject;
var
  X, Y: Integer;
begin
  CalcXY(Index, X, Y);
  if X < 0 then Result := nil else Result := FGrid.Objects[X, Y];
end;

procedure TStringGridStrings.Insert(Index: Integer; const S: string);
begin
  InvalidOp(sInvalidStringGridOp);
end;

procedure TStringGridStrings.Put(Index: Integer; const S: string);
var
  X, Y: Integer;
begin
  CalcXY(Index, X, Y);
  FGrid.Cells[X, Y] := S;
end;

procedure TStringGridStrings.PutObject(Index: Integer; AObject: TObject);
var
  X, Y: Integer;
begin
  CalcXY(Index, X, Y);
  FGrid.Objects[X, Y] := AObject;
end;

procedure TStringGridStrings.SetUpdateState(Updating: Boolean);
begin
  FGrid.SetUpdateState(Updating);
end;

{ TStringGrid }

constructor TStringGrid.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Initialize;
end;

destructor TStringGrid.Destroy;
  function FreeItem(TheIndex: Integer; TheItem: Pointer): Integer; far;
  begin
    TObject(TheItem).Free;
    Result := 0;
  end;

begin
  if FRows <> nil then
  begin
    TSparseList(FRows).ForAll(@FreeItem);
    TSparseList(FRows).Free;
  end;
  if FCols <> nil then
  begin
    TSparseList(FCols).ForAll(@FreeItem);
    TSparseList(FCols).Free;
  end;
  if FData <> nil then
  begin
    TSparseList(FData).ForAll(@FreeItem);
    TSparseList(FData).Free;
  end;
  inherited Destroy;
end;

procedure TStringGrid.ColumnMoved(FromIndex, ToIndex: Longint);

  function MoveColData(Index: Integer; ARow: TStringSparseList): Integer; far;
  begin
    ARow.Move(FromIndex, ToIndex);
    Result := 0;
  end;

begin
  TSparseList(FData).ForAll(@MoveColData);
  Invalidate;
  inherited ColumnMoved(FromIndex, ToIndex);
end;

procedure TStringGrid.RowMoved(FromIndex, ToIndex: Longint);
begin
  TSparseList(FData).Move(FromIndex, ToIndex);
  Invalidate;
  inherited RowMoved(FromIndex, ToIndex);
end;

function TStringGrid.GetEditText(ACol, ARow: Longint): string;
begin
  Result := Cells[ACol, ARow];
  if Assigned(FOnGetEditText) then FOnGetEditText(Self, ACol, ARow, Result);
end;

procedure TStringGrid.SetEditText(ACol, ARow: Longint; const Value: string);
begin
  DisableEditUpdate;
  try
    if Value <> Cells[ACol, ARow] then Cells[ACol, ARow] := Value;
  finally
    EnableEditUpdate;
  end;
  inherited SetEditText(ACol, ARow, Value);
end;

procedure TStringGrid.DrawCell(ACol, ARow: Longint; ARect: TRect;
  AState: TGridDrawState);
begin
  if DefaultDrawing then
    Canvas.TextRect(ARect, ARect.Left+2, ARect.Top+2, Cells[ACol, ARow]);
  inherited DrawCell(ACol, ARow, ARect, AState);
end;

procedure TStringGrid.DisableEditUpdate;
begin
  Inc(FEditUpdate);
end;

procedure TStringGrid.EnableEditUpdate;
begin
  Dec(FEditUpdate);
end;

procedure TStringGrid.Initialize;
var
  quantum: TSPAQuantum;
begin
  if FCols = nil then
  begin
    if ColCount > 512 then quantum := SPALarge else quantum := SPASmall;
    FCols := TSparseList.Create(quantum);
  end;
  if RowCount > 256 then quantum := SPALarge else quantum := SPASmall;
  if FRows = nil then FRows := TSparseList.Create(quantum);
  if FData = nil then FData := TSparseList.Create(quantum);
end;

procedure TStringGrid.SetUpdateState(Updating: Boolean);
begin
  FUpdating := Updating;
  if not Updating and FNeedsUpdating then
  begin
    InvalidateGrid;
    FNeedsUpdating := False;
  end;
end;

procedure TStringGrid.Update(ACol, ARow: Integer);
begin
  if not FUpdating then InvalidateCell(ACol, ARow)
  else FNeedsUpdating := True;
//  if FEditUpdate = 0 then InvalidateEditor;

//  (ACol = Col) and (ARow = Row) and
end;

function  TStringGrid.EnsureColRow(Index: Integer; IsCol: Boolean):
  TStringGridStrings;
var
  RCIndex: Integer;
  PList: ^TSparseList;
begin
  if IsCol then PList := @FCols else PList := @FRows;
  Result := TStringGridStrings(PList^[Index]);
  if Result = nil then
  begin
    if IsCol then RCIndex := -Index - 1 else RCIndex := Index + 1;
    Result := TStringGridStrings.Create(Self, RCIndex);
    PList^[Index] := Result;
  end;
end;

function  TStringGrid.EnsureDataRow(ARow: Integer): Pointer;
var
  quantum: TSPAQuantum;
begin
  Result := TStringSparseList(TSparseList(FData)[ARow]);
  if Result = nil then
  begin
    if ColCount > 512 then quantum := SPALarge else quantum := SPASmall;
    Result := TStringSparseList.Create(quantum);
    TSparseList(FData)[ARow] := Result;
  end;
end;

function TStringGrid.GetCells(ACol, ARow: Integer): string;
var
  ssl: TStringSparseList;
begin
  ssl := TStringSparseList(TSparseList(FData)[ARow]);
  if ssl = nil then Result := '' else Result := ssl[ACol];
end;

function TStringGrid.GetCols(Index: Integer): TStrings;
begin
  Result := EnsureColRow(Index, True);
end;

function TStringGrid.GetObjects(ACol, ARow: Integer): TObject;
var
  ssl: TStringSparseList;
begin
  ssl := TStringSparseList(TSparseList(FData)[ARow]);
  if ssl = nil then Result := nil else Result := ssl.Objects[ACol];
end;

function TStringGrid.GetRows(Index: Integer): TStrings;
begin
  Result := EnsureColRow(Index, False);
end;

procedure TStringGrid.SetCells(ACol, ARow: Integer; const Value: string);
begin
  TStringGridStrings(EnsureDataRow(ARow))[ACol] := Value;
  EnsureColRow(ACol, True);
  EnsureColRow(ARow, False);
  Update(ACol, ARow);
end;

procedure TStringGrid.SetCols(Index: Integer; Value: TStrings);
begin
  EnsureColRow(Index, True).Assign(Value);
end;

procedure TStringGrid.SetObjects(ACol, ARow: Integer; Value: TObject);
begin
  TStringGridStrings(EnsureDataRow(ARow)).Objects[ACol] := Value;
  EnsureColRow(ACol, True);
  EnsureColRow(ARow, False);
  Update(ACol, ARow);
end;

procedure TStringGrid.SetRows(Index: Integer; Value: TStrings);
begin
  EnsureColRow(Index, False).Assign(Value);
end;

end.
