cairo_surface_t: Cairo: A Vector Graphics Library

+ + +

cairo_surface_t

cairo_surface_t — Base class for surfaces

Functions

++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

+cairo_surface_t * +	+cairo_surface_create_similar () +
+cairo_surface_t * +	+cairo_surface_create_similar_image () +
+cairo_surface_t * +	+cairo_surface_create_for_rectangle () +
+cairo_surface_t * +	+cairo_surface_reference () +
+void +	+cairo_surface_destroy () +
+cairo_status_t +	+cairo_surface_status () +
+void +	+cairo_surface_finish () +
+void +	+cairo_surface_flush () +
+cairo_device_t * +	+cairo_surface_get_device () +
+void +	+cairo_surface_get_font_options () +
+cairo_content_t +	+cairo_surface_get_content () +
+void +	+cairo_surface_mark_dirty () +
+void +	+cairo_surface_mark_dirty_rectangle () +
+void +	+cairo_surface_set_device_offset () +
+void +	+cairo_surface_get_device_offset () +
+void +	+cairo_surface_get_device_scale () +
+void +	+cairo_surface_set_device_scale () +
+void +	+cairo_surface_set_fallback_resolution () +
+void +	+cairo_surface_get_fallback_resolution () +
+cairo_surface_type_t +	+cairo_surface_get_type () +
unsigned int +	+cairo_surface_get_reference_count () +
+cairo_status_t +	+cairo_surface_set_user_data () +
+void * +	+cairo_surface_get_user_data () +
+void +	+cairo_surface_copy_page () +
+void +	+cairo_surface_show_page () +
+cairo_bool_t +	+cairo_surface_has_show_text_glyphs () +
+cairo_status_t +	+cairo_surface_set_mime_data () +
+void +	+cairo_surface_get_mime_data () +
+cairo_bool_t +	+cairo_surface_supports_mime_type () +
+cairo_surface_t * +	+cairo_surface_map_to_image () +
+void +	+cairo_surface_unmap_image () +

Types and Values

++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

#define	CAIRO_HAS_MIME_SURFACE
#define	CAIRO_MIME_TYPE_CCITT_FAX
#define	CAIRO_MIME_TYPE_CCITT_FAX_PARAMS
#define	CAIRO_MIME_TYPE_EPS
#define	CAIRO_MIME_TYPE_EPS_PARAMS
#define	CAIRO_MIME_TYPE_JBIG2
#define	CAIRO_MIME_TYPE_JBIG2_GLOBAL
#define	CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID
#define	CAIRO_MIME_TYPE_JP2
#define	CAIRO_MIME_TYPE_JPEG
#define	CAIRO_MIME_TYPE_PNG
#define	CAIRO_MIME_TYPE_URI
#define	CAIRO_MIME_TYPE_UNIQUE_ID
typedef	cairo_surface_t
enum	cairo_content_t
enum	cairo_surface_type_t

Description

cairo_surface_t is the abstract type representing all different drawing +targets that cairo can render to. The actual drawings are +performed using a cairo context.

A cairo surface is created by using backend-specific +constructors, typically of the form +cairo_backend_surface_create().

Most surface types allow accessing the surface without using Cairo +functions. If you do this, keep in mind that it is mandatory that you call +cairo_surface_flush() before reading from or writing to the surface and that +you must use cairo_surface_mark_dirty() after modifying it.

Example 1. Directly modifying an image surface

+ + + + + + + +

1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+11
+12
+13
+14
+15
+16
+17
+18
+19

void
+modify_image_surface (cairo_surface_t *surface)
+{
+  unsigned char *data;
+  int width, height, stride;
+
+  // flush to ensure all writing to the image was done
+  cairo_surface_flush (surface);
+
+  // modify the image
+  data = cairo_image_surface_get_data (surface);
+  width = cairo_image_surface_get_width (surface);
+  height = cairo_image_surface_get_height (surface);
+  stride = cairo_image_surface_get_stride (surface);
+  modify_image_data (data, width, height, stride);
+
+  // mark the image dirty so Cairo clears its caches.
+  cairo_surface_mark_dirty (surface);
+}

+ +

Note that for other surface types it might be necessary to acquire the +surface's device first. See cairo_device_acquire() for a discussion of +devices.

Functions

cairo_surface_create_similar ()

cairo_surface_t *
+cairo_surface_create_similar (cairo_surface_t *other,
+                              cairo_content_t content,
+                              int width,
+                              int height);

Create a new surface that is as compatible as possible with an +existing surface. For example the new surface will have the same +device scale, fallback resolution and font options as +other +. Generally, the new surface will also use the same backend +as other +, unless that is not possible for some reason. The type of +the returned surface may be examined with +cairo_surface_get_type().

Initially the surface contents are all 0 (transparent if contents +have transparency, black otherwise.)

Use cairo_surface_create_similar_image() if you need an image surface +which can be painted quickly to the target surface.

Parameters

+++++ + + + + + + + + + + + + + + + + + + + + + + +

other	an existing surface used to select the backend of the new surface
content	the content for the new surface
width	width of the new surface, (in device-space units)
height	height of the new surface (in device-space units)

Returns

a pointer to the newly allocated surface. The caller +owns the surface and should call cairo_surface_destroy() when done +with it.

This function always returns a valid pointer, but it will return a +pointer to a "nil" surface if other +is already in an error state +or any other error occurs.

Since: 1.0

cairo_surface_create_similar_image ()

cairo_surface_t *
+cairo_surface_create_similar_image (cairo_surface_t *other,
+                                    cairo_format_t format,
+                                    int width,
+                                    int height);

Create a new image surface that is as compatible as possible for uploading +to and the use in conjunction with an existing surface. However, this surface +can still be used like any normal image surface. Unlike +cairo_surface_create_similar() the new image surface won't inherit +the device scale from other +.

Initially the surface contents are all 0 (transparent if contents +have transparency, black otherwise.)

Use cairo_surface_create_similar() if you don't need an image surface.

Parameters

+++++ + + + + + + + + + + + + + + + + + + + + + + +

other	an existing surface used to select the preference of the new surface
format	the format for the new surface
width	width of the new surface, (in pixels)
height	height of the new surface (in pixels)

Returns

a pointer to the newly allocated image surface. The caller +owns the surface and should call cairo_surface_destroy() when done +with it.

This function always returns a valid pointer, but it will return a +pointer to a "nil" surface if other +is already in an error state +or any other error occurs.

Since: 1.12

cairo_surface_create_for_rectangle ()

cairo_surface_t *
+cairo_surface_create_for_rectangle (cairo_surface_t *target,
+                                    double x,
+                                    double y,
+                                    double width,
+                                    double height);

Create a new surface that is a rectangle within the target surface. +All operations drawn to this surface are then clipped and translated +onto the target surface. Nothing drawn via this sub-surface outside of +its bounds is drawn onto the target surface, making this a useful method +for passing constrained child surfaces to library routines that draw +directly onto the parent surface, i.e. with no further backend allocations, +double buffering or copies.

The semantics of subsurfaces have not been finalized yet +unless the rectangle is in full device units, is contained within +the extents of the target surface, and the target or subsurface's +device transforms are not changed.

Parameters

+++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + +

target	an existing surface for which the sub-surface will point to
x	the x-origin of the sub-surface from the top-left of the target surface (in device-space units)
y	the y-origin of the sub-surface from the top-left of the target surface (in device-space units)
width	width of the sub-surface (in device-space units)
height	height of the sub-surface (in device-space units)

Returns

a pointer to the newly allocated surface. The caller +owns the surface and should call cairo_surface_destroy() when done +with it.

This function always returns a valid pointer, but it will return a +pointer to a "nil" surface if other +is already in an error state +or any other error occurs.

Since: 1.10

cairo_surface_reference ()

cairo_surface_t *
+cairo_surface_reference (cairo_surface_t *surface);

Increases the reference count on surface + by one. This prevents +surface + from being destroyed until a matching call to +cairo_surface_destroy() is made.

Use cairo_surface_get_reference_count() to get the number of +references to a cairo_surface_t.

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Returns

the referenced cairo_surface_t.

Since: 1.0

cairo_surface_destroy ()

void
+cairo_surface_destroy (cairo_surface_t *surface);

Decreases the reference count on surface + by one. If the result is +zero, then surface + and all associated resources are freed. See +cairo_surface_reference().

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Since: 1.0

cairo_surface_status ()

cairo_status_t
+cairo_surface_status (cairo_surface_t *surface);

Checks whether an error has previously occurred for this +surface.

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Returns

CAIRO_STATUS_SUCCESS, CAIRO_STATUS_NULL_POINTER, +CAIRO_STATUS_NO_MEMORY, CAIRO_STATUS_READ_ERROR, +CAIRO_STATUS_INVALID_CONTENT, CAIRO_STATUS_INVALID_FORMAT, or +CAIRO_STATUS_INVALID_VISUAL.

Since: 1.0

cairo_surface_finish ()

void
+cairo_surface_finish (cairo_surface_t *surface);

This function finishes the surface and drops all references to +external resources. For example, for the Xlib backend it means +that cairo will no longer access the drawable, which can be freed. +After calling cairo_surface_finish() the only valid operations on a +surface are getting and setting user, referencing and +destroying, and flushing and finishing it. +Further drawing to the surface will not affect the +surface but will instead trigger a CAIRO_STATUS_SURFACE_FINISHED +error.

When the last call to cairo_surface_destroy() decreases the +reference count to zero, cairo will call cairo_surface_finish() if +it hasn't been called already, before freeing the resources +associated with the surface.

Parameters

+++++ + + + + + +

surface

the cairo_surface_t to finish

Since: 1.0

cairo_surface_flush ()

void
+cairo_surface_flush (cairo_surface_t *surface);

Do any pending drawing for the surface and also restore any temporary +modifications cairo has made to the surface's state. This function +must be called before switching from drawing on the surface with +cairo to drawing on it directly with native APIs, or accessing its +memory outside of Cairo. If the surface doesn't support direct +access, then this function does nothing.

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Since: 1.0

cairo_surface_get_device ()

cairo_device_t *
+cairo_surface_get_device (cairo_surface_t *surface);

This function returns the device for a surface +. +See cairo_device_t.

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Returns

The device for surface +or NULL if the surface does +not have an associated device.

Since: 1.10

cairo_surface_get_font_options ()

void
+cairo_surface_get_font_options (cairo_surface_t *surface,
+                                cairo_font_options_t *options);

Retrieves the default font rendering options for the surface. +This allows display surfaces to report the correct subpixel order +for rendering on them, print surfaces to disable hinting of +metrics and so forth. The result can then be used with +cairo_scaled_font_create().

Parameters

+++++ + + + + + + + + + + + + +

surface	a cairo_surface_t
options	a cairo_font_options_t object into which to store +the retrieved options. All existing values are overwritten

Since: 1.0

cairo_surface_get_content ()

cairo_content_t
+cairo_surface_get_content (cairo_surface_t *surface);

This function returns the content type of surface + which indicates +whether the surface contains color and/or alpha information. See +cairo_content_t.

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Returns

The content type of surface +.

Since: 1.2

cairo_surface_mark_dirty ()

void
+cairo_surface_mark_dirty (cairo_surface_t *surface);

Tells cairo that drawing has been done to surface using means other +than cairo, and that cairo should reread any cached areas. Note +that you must call cairo_surface_flush() before doing such drawing.

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Since: 1.0

cairo_surface_mark_dirty_rectangle ()

void
+cairo_surface_mark_dirty_rectangle (cairo_surface_t *surface,
+                                    int x,
+                                    int y,
+                                    int width,
+                                    int height);

Like cairo_surface_mark_dirty(), but drawing has been done only to +the specified rectangle, so that cairo can retain cached contents +for other parts of the surface.

Any cached clip set on the surface will be reset by this function, +to make sure that future cairo calls have the clip set that they +expect.

Parameters

+++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + +

surface	a cairo_surface_t
x	X coordinate of dirty rectangle
y	Y coordinate of dirty rectangle
width	width of dirty rectangle
height	height of dirty rectangle

Since: 1.0

cairo_surface_set_device_offset ()

void
+cairo_surface_set_device_offset (cairo_surface_t *surface,
+                                 double x_offset,
+                                 double y_offset);

Sets an offset that is added to the device coordinates determined +by the CTM when drawing to surface +. One use case for this function +is when we want to create a cairo_surface_t that redirects drawing +for a portion of an onscreen surface to an offscreen surface in a +way that is completely invisible to the user of the cairo +API. Setting a transformation via cairo_translate() isn't +sufficient to do this, since functions like +cairo_device_to_user() will expose the hidden offset.

Note that the offset affects drawing to the surface as well as +using the surface in a source pattern.

Parameters

+++++ + + + + + + + + + + + + + + + + + +

surface	a cairo_surface_t
x_offset	the offset in the X direction, in device units
y_offset	the offset in the Y direction, in device units

Since: 1.0

cairo_surface_get_device_offset ()

void
+cairo_surface_get_device_offset (cairo_surface_t *surface,
+                                 double *x_offset,
+                                 double *y_offset);

This function returns the previous device offset set by +cairo_surface_set_device_offset().

Parameters

+++++ + + + + + + + + + + + + + + + + + +

surface	a cairo_surface_t
x_offset	the offset in the X direction, in device units
y_offset	the offset in the Y direction, in device units

Since: 1.2

cairo_surface_get_device_scale ()

void
+cairo_surface_get_device_scale (cairo_surface_t *surface,
+                                double *x_scale,
+                                double *y_scale);

This function returns the previous device offset set by +cairo_surface_set_device_scale().

Parameters

+++++ + + + + + + + + + + + + + + + + + +

surface	a cairo_surface_t
x_scale	the scale in the X direction, in device units
y_scale	the scale in the Y direction, in device units

Since: 1.14

cairo_surface_set_device_scale ()

void
+cairo_surface_set_device_scale (cairo_surface_t *surface,
+                                double x_scale,
+                                double y_scale);

Sets a scale that is multiplied to the device coordinates determined +by the CTM when drawing to surface +. One common use for this is to +render to very high resolution display devices at a scale factor, so +that code that assumes 1 pixel will be a certain size will still work. +Setting a transformation via cairo_translate() isn't +sufficient to do this, since functions like +cairo_device_to_user() will expose the hidden scale.

Note that the scale affects drawing to the surface as well as +using the surface in a source pattern.

Parameters

+++++ + + + + + + + + + + + + + + + + + +

surface	a cairo_surface_t
x_scale	a scale factor in the X direction
y_scale	a scale factor in the Y direction

Since: 1.14

cairo_surface_set_fallback_resolution ()

void
+cairo_surface_set_fallback_resolution (cairo_surface_t *surface,
+                                       double x_pixels_per_inch,
+                                       double y_pixels_per_inch);

Set the horizontal and vertical resolution for image fallbacks.

When certain operations aren't supported natively by a backend, +cairo will fallback by rendering operations to an image and then +overlaying that image onto the output. For backends that are +natively vector-oriented, this function can be used to set the +resolution used for these image fallbacks, (larger values will +result in more detailed images, but also larger file sizes).

Some examples of natively vector-oriented backends are the ps, pdf, +and svg backends.

For backends that are natively raster-oriented, image fallbacks are +still possible, but they are always performed at the native +device resolution. So this function has no effect on those +backends.

Note: The fallback resolution only takes effect at the time of +completing a page (with cairo_show_page() or cairo_copy_page()) so +there is currently no way to have more than one fallback resolution +in effect on a single page.

The default fallback resoultion is 300 pixels per inch in both +dimensions.

Parameters

+++++ + + + + + + + + + + + + + + + + + +

surface	a cairo_surface_t
x_pixels_per_inch	horizontal setting for pixels per inch
y_pixels_per_inch	vertical setting for pixels per inch

Since: 1.2

cairo_surface_get_fallback_resolution ()

void
+cairo_surface_get_fallback_resolution (cairo_surface_t *surface,
+                                       double *x_pixels_per_inch,
+                                       double *y_pixels_per_inch);

This function returns the previous fallback resolution set by +cairo_surface_set_fallback_resolution(), or default fallback +resolution if never set.

Parameters

+++++ + + + + + + + + + + + + + + + + + +

surface	a cairo_surface_t
x_pixels_per_inch	horizontal pixels per inch
y_pixels_per_inch	vertical pixels per inch

Since: 1.8

cairo_surface_get_type ()

cairo_surface_type_t
+cairo_surface_get_type (cairo_surface_t *surface);

This function returns the type of the backend used to create +a surface. See cairo_surface_type_t for available types.

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Returns

The type of surface +.

Since: 1.2

cairo_surface_get_reference_count ()

unsigned int
+cairo_surface_get_reference_count (cairo_surface_t *surface);

Returns the current reference count of surface +.

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Returns

the current reference count of surface +. If the +object is a nil object, 0 will be returned.

Since: 1.4

cairo_surface_set_user_data ()

cairo_status_t
+cairo_surface_set_user_data (cairo_surface_t *surface,
+                             const cairo_user_data_key_t *key,
+                             void *user_data,
+                             cairo_destroy_func_t destroy);

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

Parameters

+++++ + + + + + + + + + + + + + + + + + + + + + + +

surface	a cairo_surface_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 surface
destroy	a cairo_destroy_func_t which will be called when the +surface 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_surface_get_user_data ()

void *
+cairo_surface_get_user_data (cairo_surface_t *surface,
+                             const cairo_user_data_key_t *key);

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

Parameters

+++++ + + + + + + + + + + + + +

surface	a cairo_surface_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

cairo_surface_copy_page ()

void
+cairo_surface_copy_page (cairo_surface_t *surface);

Emits the current page for backends that support multiple pages, +but doesn't clear it, so that the contents of the current page will +be retained for the next page. Use cairo_surface_show_page() if you +want to get an empty page after the emission.

There is a convenience function for this that takes a cairo_t, +namely cairo_copy_page().

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Since: 1.6

cairo_surface_show_page ()

void
+cairo_surface_show_page (cairo_surface_t *surface);

Emits and clears the current page for backends that support multiple +pages. Use cairo_surface_copy_page() if you don't want to clear the page.

There is a convenience function for this that takes a cairo_t, +namely cairo_show_page().

Parameters

+++++ + + + + + +

surface

a cairo_Surface_t

Since: 1.6

cairo_surface_has_show_text_glyphs ()

cairo_bool_t
+cairo_surface_has_show_text_glyphs (cairo_surface_t *surface);

Returns whether the surface supports +sophisticated cairo_show_text_glyphs() operations. That is, +whether it actually uses the provided text and cluster data +to a cairo_show_text_glyphs() call.

Note: Even if this function returns FALSE, a +cairo_show_text_glyphs() operation targeted at surface + will +still succeed. It just will +act like a cairo_show_glyphs() operation. Users can use this +function to avoid computing UTF-8 text and cluster mapping if the +target surface does not use it.

Parameters

+++++ + + + + + +

surface

a cairo_surface_t

Returns

TRUE if surface +supports +cairo_show_text_glyphs(), FALSE otherwise

Since: 1.8

cairo_surface_set_mime_data ()

cairo_status_t
+cairo_surface_set_mime_data (cairo_surface_t *surface,
+                             const char *mime_type,
+                             const unsigned char *data,
+                             unsigned long  length,
+                             cairo_destroy_func_t destroy,
+                             void *closure);

Attach an image in the format mime_type + to surface +. To remove +the data from a surface, call this function with same mime type +and NULL for data +.

The attached image (or filename) data can later be used by backends +which support it (currently: PDF, PS, SVG and Win32 Printing +surfaces) to emit this data instead of making a snapshot of the +surface +. This approach tends to be faster and requires less +memory and disk space.

The recognized MIME types are the following: CAIRO_MIME_TYPE_JPEG, +CAIRO_MIME_TYPE_PNG, CAIRO_MIME_TYPE_JP2, CAIRO_MIME_TYPE_URI, +CAIRO_MIME_TYPE_UNIQUE_ID, CAIRO_MIME_TYPE_JBIG2, +CAIRO_MIME_TYPE_JBIG2_GLOBAL, CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID, +CAIRO_MIME_TYPE_CCITT_FAX, CAIRO_MIME_TYPE_CCITT_FAX_PARAMS.

See corresponding backend surface docs for details about which MIME +types it can handle. Caution: the associated MIME data will be +discarded if you draw on the surface afterwards. Use this function +with care.

Even if a backend supports a MIME type, that does not mean cairo +will always be able to use the attached MIME data. For example, if +the backend does not natively support the compositing operation used +to apply the MIME data to the backend. In that case, the MIME data +will be ignored. Therefore, to apply an image in all cases, it is best +to create an image surface which contains the decoded image data and +then attach the MIME data to that. This ensures the image will always +be used while still allowing the MIME data to be used whenever +possible.

Parameters

+++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

surface	a cairo_surface_t
mime_type	the MIME type of the image data
data	the image data to attach to the surface
length	the length of the image data
destroy	a cairo_destroy_func_t which will be called when the +surface is destroyed or when new image data is attached using the +same mime type.
closure	the data to be passed to the `destroy` +notifier

Returns

CAIRO_STATUS_SUCCESS or CAIRO_STATUS_NO_MEMORY if a +slot could not be allocated for the user data.

Since: 1.10

cairo_surface_get_mime_data ()

void
+cairo_surface_get_mime_data (cairo_surface_t *surface,
+                             const char *mime_type,
+                             const unsigned char **data,
+                             unsigned long *length);

Return mime data previously attached to surface + using the +specified mime type. If no data has been attached with the given +mime type, data + is set NULL.

Parameters

+++++ + + + + + + + + + + + + + + + + + + + + + + +

surface	a cairo_surface_t
mime_type	the mime type of the image data
data	the image data to attached to the surface
length	the length of the image data

Since: 1.10

cairo_surface_supports_mime_type ()

cairo_bool_t
+cairo_surface_supports_mime_type (cairo_surface_t *surface,
+                                  const char *mime_type);

Return whether surface + supports mime_type +.

Parameters

+++++ + + + + + + + + + + + + +

surface	a cairo_surface_t
mime_type	the mime type

Returns

TRUE if surface +supports +mime_type +, FALSE otherwise

Since: 1.12

cairo_surface_map_to_image ()

cairo_surface_t *
+cairo_surface_map_to_image (cairo_surface_t *surface,
+                            const cairo_rectangle_int_t *extents);

Returns an image surface that is the most efficient mechanism for +modifying the backing store of the target surface. The region retrieved +may be limited to the extents + or NULL for the whole surface

Note, the use of the original surface as a target or source whilst +it is mapped is undefined. The result of mapping the surface +multiple times is undefined. Calling cairo_surface_destroy() or +cairo_surface_finish() on the resulting image surface results in +undefined behavior. Changing the device transform of the image +surface or of surface + before the image surface is unmapped results +in undefined behavior.

Parameters

+++++ + + + + + + + + + + + + +

surface	an existing surface used to extract the image from
extents	limit the extraction to an rectangular region

Returns

a pointer to the newly allocated image surface. The caller +must use cairo_surface_unmap_image() to destroy this image surface.

This function always returns a valid pointer, but it will return a +pointer to a "nil" surface if other +is already in an error state +or any other error occurs. If the returned pointer does not have an +error status, it is guaranteed to be an image surface whose format +is not CAIRO_FORMAT_INVALID.

Since: 1.12

cairo_surface_unmap_image ()

void
+cairo_surface_unmap_image (cairo_surface_t *surface,
+                           cairo_surface_t *image);

Unmaps the image surface as returned from cairo_surface_map_to_image().

The content of the image will be uploaded to the target surface. +Afterwards, the image is destroyed.

Using an image surface which wasn't returned by cairo_surface_map_to_image() +results in undefined behavior.

Parameters

+++++ + + + + + + + + + + + + +

surface	the surface passed to `cairo_surface_map_to_image()`.
image	the currently mapped image

Since: 1.12

Types and Values

CAIRO_HAS_MIME_SURFACE

#define CAIRO_HAS_MIME_SURFACE 1
+

CAIRO_MIME_TYPE_CCITT_FAX

#define CAIRO_MIME_TYPE_CCITT_FAX "image/g3fax"
+

Group 3 or Group 4 CCITT facsimile encoding (International +Telecommunication Union, Recommendations T.4 and T.6.)

Since: 1.16

CAIRO_MIME_TYPE_CCITT_FAX_PARAMS

#define CAIRO_MIME_TYPE_CCITT_FAX_PARAMS "application/x-cairo.ccitt.params"
+

Decode parameters for Group 3 or Group 4 CCITT facsimile encoding. +See CCITT Fax Images.

Since: 1.16

CAIRO_MIME_TYPE_EPS

#define CAIRO_MIME_TYPE_EPS "application/postscript"
+

Encapsulated PostScript file. +Encapsulated PostScript File Format Specification

Since: 1.16

CAIRO_MIME_TYPE_EPS_PARAMS

#define CAIRO_MIME_TYPE_EPS_PARAMS "application/x-cairo.eps.params"
+

Embedding parameters Encapsulated PostScript data. +See Embedding EPS files.

Since: 1.16

CAIRO_MIME_TYPE_JBIG2

#define CAIRO_MIME_TYPE_JBIG2 "application/x-cairo.jbig2"
+

Joint Bi-level Image Experts Group image coding standard (ISO/IEC 11544).

Since: 1.14

CAIRO_MIME_TYPE_JBIG2_GLOBAL

#define CAIRO_MIME_TYPE_JBIG2_GLOBAL "application/x-cairo.jbig2-global"
+

Joint Bi-level Image Experts Group image coding standard (ISO/IEC 11544) global segment.

Since: 1.14

CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID

#define CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID "application/x-cairo.jbig2-global-id"
+

An unique identifier shared by a JBIG2 global segment and all JBIG2 images +that depend on the global segment.

Since: 1.14

CAIRO_MIME_TYPE_JP2

#define CAIRO_MIME_TYPE_JP2 "image/jp2"
+

The Joint Photographic Experts Group (JPEG) 2000 image coding standard (ISO/IEC 15444-1).

Since: 1.10

CAIRO_MIME_TYPE_JPEG

#define CAIRO_MIME_TYPE_JPEG "image/jpeg"
+

The Joint Photographic Experts Group (JPEG) image coding standard (ISO/IEC 10918-1).

Since: 1.10

CAIRO_MIME_TYPE_PNG

#define CAIRO_MIME_TYPE_PNG "image/png"
+

The Portable Network Graphics image file format (ISO/IEC 15948).

Since: 1.10

CAIRO_MIME_TYPE_URI

#define CAIRO_MIME_TYPE_URI "text/x-uri"
+

URI for an image file (unofficial MIME type).

Since: 1.10

CAIRO_MIME_TYPE_UNIQUE_ID

#define CAIRO_MIME_TYPE_UNIQUE_ID "application/x-cairo.uuid"
+

Unique identifier for a surface (cairo specific MIME type). All surfaces with +the same unique identifier will only be embedded once.

Since: 1.12

cairo_surface_t

typedef struct _cairo_surface cairo_surface_t;
+

A cairo_surface_t represents an image, either as the destination +of a drawing operation or as source when drawing onto another +surface. To draw to a cairo_surface_t, create a cairo context +with the surface as the target, using cairo_create().

There are different subtypes of cairo_surface_t for +different drawing backends; for example, cairo_image_surface_create() +creates a bitmap image in memory. +The type of a surface can be queried with cairo_surface_get_type().

The initial contents of a surface after creation depend upon the manner +of its creation. If cairo creates the surface and backing storage for +the user, it will be initially cleared; for example, +cairo_image_surface_create() and cairo_surface_create_similar(). +Alternatively, if the user passes in a reference to some backing storage +and asks cairo to wrap that in a cairo_surface_t, then the contents are +not modified; for example, cairo_image_surface_create_for_data() and +cairo_xlib_surface_create().

Memory management of cairo_surface_t is done with +cairo_surface_reference() and cairo_surface_destroy().

Since: 1.0

enum cairo_content_t

cairo_content_t is used to describe the content that a surface will +contain, whether color information, alpha information (translucence +vs. opacity), or both.

Note: The large values here are designed to keep cairo_content_t +values distinct from cairo_format_t values so that the +implementation can detect the error if users confuse the two types.

Members

+++++ + + + + + + + + + + + + + + + + + +

CAIRO_CONTENT_COLOR	+ The surface will hold color content only. (Since 1.0) +
CAIRO_CONTENT_ALPHA	+ The surface will hold alpha content only. (Since 1.0) +
CAIRO_CONTENT_COLOR_ALPHA	+ The surface will hold color and alpha content. (Since 1.0) +

Since: 1.0

enum cairo_surface_type_t

cairo_surface_type_t is used to describe the type of a given +surface. The surface types are also known as "backends" or "surface +backends" within cairo.

The type of a surface is determined by the function used to create +it, which will generally be of the form +cairo_type_surface_create(), +(though see cairo_surface_create_similar() as well).

The surface type can be queried with cairo_surface_get_type()

The various cairo_surface_t functions can be used with surfaces of +any type, but some backends also provide type-specific functions +that must only be called with a surface of the appropriate +type. These functions have names that begin with +cairo_type_surface such as cairo_image_surface_get_width().

The behavior of calling a type-specific function with a surface of +the wrong type is undefined.

New entries may be added in future versions.

Members

+++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

CAIRO_SURFACE_TYPE_IMAGE	+ The surface is of type image, since 1.2 +
CAIRO_SURFACE_TYPE_PDF	+ The surface is of type pdf, since 1.2 +
CAIRO_SURFACE_TYPE_PS	+ The surface is of type ps, since 1.2 +
CAIRO_SURFACE_TYPE_XLIB	+ The surface is of type xlib, since 1.2 +
CAIRO_SURFACE_TYPE_XCB	+ The surface is of type xcb, since 1.2 +
CAIRO_SURFACE_TYPE_GLITZ	+ The surface is of type glitz, since 1.2 +
CAIRO_SURFACE_TYPE_QUARTZ	+ The surface is of type quartz, since 1.2 +
CAIRO_SURFACE_TYPE_WIN32	+ The surface is of type win32, since 1.2 +
CAIRO_SURFACE_TYPE_BEOS	+ The surface is of type beos, since 1.2 +
CAIRO_SURFACE_TYPE_DIRECTFB	+ The surface is of type directfb, since 1.2 +
CAIRO_SURFACE_TYPE_SVG	+ The surface is of type svg, since 1.2 +
CAIRO_SURFACE_TYPE_OS2	+ The surface is of type os2, since 1.4 +
CAIRO_SURFACE_TYPE_WIN32_PRINTING	+ The surface is a win32 printing surface, since 1.6 +
CAIRO_SURFACE_TYPE_QUARTZ_IMAGE	+ The surface is of type quartz_image, since 1.6 +
CAIRO_SURFACE_TYPE_SCRIPT	+ The surface is of type script, since 1.10 +
CAIRO_SURFACE_TYPE_QT	+ The surface is of type Qt, since 1.10 +
CAIRO_SURFACE_TYPE_RECORDING	+ The surface is of type recording, since 1.10 +
CAIRO_SURFACE_TYPE_VG	+ The surface is a OpenVG surface, since 1.10 +
CAIRO_SURFACE_TYPE_GL	+ The surface is of type OpenGL, since 1.10 +
CAIRO_SURFACE_TYPE_DRM	+ The surface is of type Direct Render Manager, since 1.10 +
CAIRO_SURFACE_TYPE_TEE	+ The surface is of type 'tee' (a multiplexing surface), since 1.10 +
CAIRO_SURFACE_TYPE_XML	+ The surface is of type XML (for debugging), since 1.10 +
CAIRO_SURFACE_TYPE_SKIA
CAIRO_SURFACE_TYPE_SUBSURFACE	+ The surface is a subsurface created with + `cairo_surface_create_for_rectangle()`, since 1.10 +
CAIRO_SURFACE_TYPE_COGL	+ This surface is of type Cogl, since 1.12 +

Since: 1.2