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Cairo: A Vector Graphics Library | ![]() |
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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);
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().
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_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. |
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_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. |
typedef enum _cairo_font_type { CAIRO_FONT_TYPE_TOY, CAIRO_FONT_TYPE_FT, CAIRO_FONT_TYPE_WIN32, CAIRO_FONT_TYPE_QUARTZ } 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.
Since 1.2
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
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_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. |
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. |