## cairo_font_face_t

cairo_font_face_t — Base class for font faces

## Synopsis

    typedef             cairo_font_face_t;
    cairo_font_face_t * cairo_font_face_reference           (cairo_font_face_t *font_face);
    void                cairo_font_face_destroy             (cairo_font_face_t *font_face);
    cairo_status_t      cairo_font_face_status              (cairo_font_face_t *font_face);
    enum                cairo_font_type_t;
    cairo_font_type_t   cairo_font_face_get_type            (cairo_font_face_t *font_face);
    unsigned int        cairo_font_face_get_reference_count (cairo_font_face_t *font_face);
    cairo_status_t      cairo_font_face_set_user_data       (cairo_font_face_t *font_face,
                                                             const cairo_user_data_key_t *key,
                                                             void *user_data,
                                                             cairo_destroy_func_t destroy);
    void *              cairo_font_face_get_user_data       (cairo_font_face_t *font_face,
                                                             const cairo_user_data_key_t *key);

## Description

cairo_font_face_t represents a particular font at a particular weight, slant, and other characteristic but no size, transformation, or size.

Font faces are created using font-backend-specific constructors, typically of the form cairo_backend`_font_face_create()`, or implicitly using the toy text API by way of `cairo_select_font_face()`. The resulting face can be accessed using `cairo_get_font_face()`.

## Details

### cairo_font_face_t

    typedef struct _cairo_font_face cairo_font_face_t;

A cairo_font_face_t specifies all aspects of a font other than the size or font matrix (a font matrix is used to distort a font by sheering it or scaling it unequally in the two directions) . A font face can be set on a cairo_t by using `cairo_set_font_face()`; the size and font matrix are set with `cairo_set_font_size()` and `cairo_set_font_matrix()`.

There are various types of font faces, depending on the font backend they use. The type of a font face can be queried using `cairo_font_face_get_type()`.

Memory management of cairo_font_face_t is done with `cairo_font_face_reference()` and `cairo_font_face_destroy()`.

### cairo_font_face_reference ()

    cairo_font_face_t * cairo_font_face_reference           (cairo_font_face_t *font_face);

Increases the reference count on `font_face` by one. This prevents `font_face` from being destroyed until a matching call to `cairo_font_face_destroy()` is made.

The number of references to a cairo_font_face_t can be get using `cairo_font_face_get_reference_count()`.

`font_face` : | a cairo_font_face_t, (may be `NULL` in which case this function does nothing).
Returns : | the referenced cairo_font_face_t.

### cairo_font_face_destroy ()

    void                cairo_font_face_destroy             (cairo_font_face_t *font_face);

Decreases the reference count on `font_face` by one. If the result is zero, then `font_face` and all associated resources are freed. See `cairo_font_face_reference()`.

`font_face` : | a cairo_font_face_t

### cairo_font_face_status ()

    cairo_status_t      cairo_font_face_status              (cairo_font_face_t *font_face);

Checks whether an error has previously occurred for this font face

`font_face` : | a cairo_font_face_t
Returns : | `CAIRO_STATUS_SUCCESS` or another error such as `CAIRO_STATUS_NO_MEMORY`.

### enum cairo_font_type_t

    typedef enum _cairo_font_type {
        CAIRO_FONT_TYPE_TOY,
        CAIRO_FONT_TYPE_FT,
        CAIRO_FONT_TYPE_WIN32,
        CAIRO_FONT_TYPE_QUARTZ,
        CAIRO_FONT_TYPE_USER
    } cairo_font_type_t;

cairo_font_type_t is used to describe the type of a given font face or scaled font. The font types are also known as "font backends" within cairo.

The type of a font face is determined by the function used to create it, which will generally be of the form cairo_type`_font_face_create()`. The font face type can be queried with `cairo_font_face_get_type()`

The various cairo_font_face_t functions can be used with a font face of any type.

The type of a scaled font is determined by the type of the font face passed to `cairo_scaled_font_create()`. The scaled font type can be queried with `cairo_scaled_font_get_type()`

The various cairo_scaled_font_t functions can be used with scaled fonts of any type, but some font backends also provide type-specific functions that must only be called with a scaled font of the appropriate type. These functions have names that begin with cairo_type`_scaled_font()` such as `cairo_ft_scaled_font_lock_face()`.

The behavior of calling a type-specific function with a scaled font of the wrong type is undefined.

New entries may be added in future versions.

`CAIRO_FONT_TYPE_TOY` | The font was created using cairo's toy font api
`CAIRO_FONT_TYPE_FT` | The font is of type FreeType
`CAIRO_FONT_TYPE_WIN32` | The font is of type Win32
`CAIRO_FONT_TYPE_QUARTZ` | The font is of type Quartz (Since: 1.6)
`CAIRO_FONT_TYPE_USER` | The font was create using cairo's user font api (Since: 1.8)

Since 1.2

### cairo_font_face_get_type ()

    cairo_font_type_t   cairo_font_face_get_type            (cairo_font_face_t *font_face);

This function returns the type of the backend used to create a font face. See cairo_font_type_t for available types.

`font_face` : | a font face
Returns : | The type of `font_face`.

Since 1.2

### cairo_font_face_get_reference_count ()

    unsigned int        cairo_font_face_get_reference_count (cairo_font_face_t *font_face);

Returns the current reference count of `font_face`.

`font_face` : | a cairo_font_face_t
Returns : | the current reference count of `font_face`. If the object is a nil object, 0 will be returned.

Since 1.4

### cairo_font_face_set_user_data ()

    cairo_status_t      cairo_font_face_set_user_data       (cairo_font_face_t *font_face,
                                                             const cairo_user_data_key_t *key,
                                                             void *user_data,
                                                             cairo_destroy_func_t destroy);

Attach user data to `font_face`. To remove user data from a font face, call this function with the key that was used to set it and `NULL` for `data`.

`font_face` : | a cairo_font_face_t
`key` : | the address of a cairo_user_data_key_t to attach the user data to
`user_data` : | the user data to attach to the font face
`destroy` : | a cairo_destroy_func_t which will be called when the font face is destroyed or when new user data is attached using the same key.
Returns : | `CAIRO_STATUS_SUCCESS` or `CAIRO_STATUS_NO_MEMORY` if a slot could not be allocated for the user data.

### cairo_font_face_get_user_data ()

    void *              cairo_font_face_get_user_data       (cairo_font_face_t *font_face,
                                                             const cairo_user_data_key_t *key);

Return user data previously attached to `font_face` using the specified key. If no user data has been attached with the given key this function returns `NULL`.

`font_face` : | a cairo_font_face_t
`key` : | the address of the cairo_user_data_key_t the user data was attached to
Returns : | the user data previously attached or `NULL`.

## See Also

cairo_scaled_font_t