Method Cairo.Surface()->map_to_image()

Method map_to_image

Surface map_to_image(RectangleInt|void extents)

Description

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 the whole surface if no extents are given.

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. Destroying or calling 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.

Parameter extents

limit the extraction to an rectangular region

Returns

a newly allocated image surface. The caller must use unmap_image() to destroy this image surface.