cairo_font_face_t: Cairo: A Vector Graphics Library

## cairo_font_face_t

cairo_font_face_t — Base class for font faces

## Functions

cairo_font_face_t * | cairo_font_face_reference ()
void | cairo_font_face_destroy ()
cairo_status_t | cairo_font_face_status ()
cairo_font_type_t | cairo_font_face_get_type ()
unsigned int | cairo_font_face_get_reference_count ()
cairo_status_t | cairo_font_face_set_user_data ()
void * | cairo_font_face_get_user_data ()

## Types and Values

typedef | cairo_font_face_t
enum | cairo_font_type_t

## 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()`.

## Functions

### 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.

Use `cairo_font_face_get_reference_count()` to get the number of references to a cairo_font_face_t.

#### Parameters

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

#### Returns

the referenced cairo_font_face_t.

Since: 1.0

### 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()`.

#### Parameters

font_face | a cairo_font_face_t |

Since: 1.0

### 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

#### Parameters

font_face | a cairo_font_face_t |

#### Returns

`CAIRO_STATUS_SUCCESS` or another error such as `CAIRO_STATUS_NO_MEMORY`.

Since: 1.0

### 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.

#### Parameters

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` .

#### Parameters

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` .

#### Parameters

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.

Since: 1.0

### 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`.

#### Parameters

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`.

Since: 1.0

## Types and Values

### 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 shearing 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()`.

Since: 1.0

### enum 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.

#### Members

CAIRO_FONT_TYPE_TOY | The font was created using cairo's toy font api (Since: 1.2) |
CAIRO_FONT_TYPE_FT | The font is of type FreeType (Since: 1.2) |
CAIRO_FONT_TYPE_WIN32 | The font is of type Win32 (Since: 1.2) |
CAIRO_FONT_TYPE_QUARTZ | The font is of type Quartz (Since: 1.6, in 1.2 and 1.4 it was named CAIRO_FONT_TYPE_ATSUI) |
CAIRO_FONT_TYPE_USER | The font was create using cairo's user font api (Since: 1.8) |
CAIRO_FONT_TYPE_DWRITE | The font is of type Win32 DWrite (Since: 1.18) |

Since: 1.2

## See Also

cairo_scaled_font_t