manpagez: man pages & more
html files: cairo
Home | html | info | man

Recording Surfaces

Recording Surfaces — Records all drawing operations

Types and Values

Description

A recording surface is a surface that records all drawing operations at the highest level of the surface backend interface, (that is, the level of paint, mask, stroke, fill, and show_text_glyphs). The recording surface can then be "replayed" against any target surface by using it as a source surface.

If you want to replay a surface so that the results in target will be identical to the results that would have been obtained if the original operations applied to the recording surface had instead been applied to the target surface, you can use code like this:

cairo_t *cr;

cr = cairo_create (target);
cairo_set_source_surface (cr, recording_surface, 0.0, 0.0);
cairo_paint (cr);
cairo_destroy (cr);

A recording surface is logically unbounded, i.e. it has no implicit constraint on the size of the drawing surface. However, in practice this is rarely useful as you wish to replay against a particular target surface with known bounds. For this case, it is more efficient to specify the target extents to the recording surface upon creation.

The recording phase of the recording surface is careful to snapshot all necessary objects (paths, patterns, etc.), in order to achieve accurate replay. The efficiency of the recording surface could be improved by improving the implementation of snapshot for the various objects. For example, it would be nice to have a copy-on-write implementation for _cairo_surface_snapshot.

Functions

cairo_recording_surface_create ()

cairo_surface_t *
cairo_recording_surface_create (cairo_content_t content,
                                const cairo_rectangle_t *extents);

Creates a recording-surface which can be used to record all drawing operations at the highest level (that is, the level of paint, mask, stroke, fill and show_text_glyphs). The recording surface can then be "replayed" against any target surface by using it as a source to drawing operations.

The recording phase of the recording surface is careful to snapshot all necessary objects (paths, patterns, etc.), in order to achieve accurate replay.

Parameters

content

the content of the recording surface

 

extents

the extents to record in pixels, can be NULL to record unbounded operations.

 

Returns

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

Since: 1.10


cairo_recording_surface_ink_extents ()

void
cairo_recording_surface_ink_extents (cairo_surface_t *surface,
                                     double *x0,
                                     double *y0,
                                     double *width,
                                     double *height);

Measures the extents of the operations stored within the recording-surface. This is useful to compute the required size of an image surface (or equivalent) into which to replay the full sequence of drawing operations.

Parameters

surface

a cairo_recording_surface_t

 

x0

the x-coordinate of the top-left of the ink bounding box

 

y0

the y-coordinate of the top-left of the ink bounding box

 

width

the width of the ink bounding box

 

height

the height of the ink bounding box

 

Since: 1.10


cairo_recording_surface_get_extents ()

cairo_bool_t
cairo_recording_surface_get_extents (cairo_surface_t *surface,
                                     cairo_rectangle_t *extents);

Get the extents of the recording-surface.

Parameters

surface

a cairo_recording_surface_t

 

extents

the cairo_rectangle_t to be assigned the extents

 

Returns

TRUE if the surface is bounded, of recording type, and not in an error state, otherwise FALSE

Since: 1.12

Types and Values

CAIRO_HAS_RECORDING_SURFACE

#define CAIRO_HAS_RECORDING_SURFACE 1

Defined if the recording surface backend is available. The recording surface backend is always built in. This macro was added for completeness in cairo 1.10.

Since: 1.10

See Also

cairo_surface_t

© manpagez.com 2000-2017
Individual documents may contain additional copyright information.