/**
* _cairo_surface_snapshot:
* @surface: a #cairo_surface_t
*
* Make an immutable reference to @surface. It is an error to call a
* surface-modifying function on the result of this function. The
* resulting 'snapshot' is a lazily copied-on-write surface i.e. it
* remains a reference to the original surface until that surface is
* written to again, at which time a copy is made of the original surface
* and the snapshot then points to that instead. Multiple snapshots of the
* same unmodified surface point to the same copy.
*
* The caller owns the return value and should call
* cairo_surface_destroy() when finished with it. This function will not
* return %NULL, but will return a nil surface instead.
*
* Return value: The snapshot surface. Note that the return surface
* may not necessarily be of the same type as @surface.
**/
cairo_surface_t *
_cairo_surface_snapshot (cairo_surface_t *surface)
{
cairo_surface_snapshot_t *snapshot;
cairo_status_t status;
TRACE ((stderr, "%s: target=%d\n", __FUNCTION__, surface->unique_id));
if (unlikely (surface->status))
return _cairo_surface_create_in_error (surface->status);
if (unlikely (surface->finished))
return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_FINISHED));
if (surface->snapshot_of != NULL)
return cairo_surface_reference (surface);
if (_cairo_surface_is_snapshot (surface))
return cairo_surface_reference (surface);
snapshot = (cairo_surface_snapshot_t *)
_cairo_surface_has_snapshot (surface, &_cairo_surface_snapshot_backend);
if (snapshot != NULL)
return cairo_surface_reference (&snapshot->base);
snapshot = malloc (sizeof (cairo_surface_snapshot_t));
if (unlikely (snapshot == NULL))
return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_FINISHED));
_cairo_surface_init (&snapshot->base,
&_cairo_surface_snapshot_backend,
NULL, /* device */
surface->content);
snapshot->base.type = surface->type;
CAIRO_MUTEX_INIT (snapshot->mutex);
snapshot->target = surface;
snapshot->clone = NULL;
status = _cairo_surface_copy_mime_data (&snapshot->base, surface);
if (unlikely (status)) {
cairo_surface_destroy (&snapshot->base);
return _cairo_surface_create_in_error (status);
}
snapshot->base.device_transform = surface->device_transform;
snapshot->base.device_transform_inverse = surface->device_transform_inverse;
_cairo_surface_attach_snapshot (surface,
&snapshot->base,
_cairo_surface_snapshot_copy_on_write);
return &snapshot->base;
}
/**
* _cairo_surface_snapshot
* @surface: a #cairo_surface_t
*
* Make an immutable reference to @surface. It is an error to call a
* surface-modifying function on the result of this function. The
* resulting 'snapshot' is a lazily copied-on-write surface i.e. it
* remains a reference to the original surface until that surface is
* written to again, at which time a copy is made of the original surface
* and the snapshot then points to that instead. Multiple snapshots of the
* same unmodified surface point to the same copy.
*
* The caller owns the return value and should call
* cairo_surface_destroy() when finished with it. This function will not
* return %NULL, but will return a nil surface instead.
*
* Return value: The snapshot surface. Note that the return surface
* may not necessarily be of the same type as @surface.
**/
cairo_surface_t *
_cairo_surface_snapshot (cairo_surface_t *surface)
{
cairo_surface_snapshot_t *snapshot;
cairo_status_t status;
if (unlikely (surface->status))
return _cairo_surface_create_in_error (surface->status);
if (surface->finished)
return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_FINISHED));
if (surface->snapshot_of != NULL)
return cairo_surface_reference (surface);
if (surface->backend->snapshot != NULL) {
cairo_surface_t *snap;
snap = _cairo_surface_has_snapshot (surface, surface->backend);
if (snap != NULL)
return cairo_surface_reference (snap);
snap = surface->backend->snapshot (surface);
if (snap != NULL) {
if (unlikely (snap->status))
return snap;
status = _cairo_surface_copy_mime_data (snap, surface);
if (unlikely (status)) {
cairo_surface_destroy (snap);
return _cairo_surface_create_in_error (status);
}
snap->device_transform = surface->device_transform;
snap->device_transform_inverse = surface->device_transform_inverse;
cairo_surface_attach_snapshot (surface, snap, NULL);
return snap;
}
}
snapshot = (cairo_surface_snapshot_t *)
_cairo_surface_has_snapshot (surface, &_cairo_surface_snapshot_backend);
if (snapshot != NULL)
return cairo_surface_reference (&snapshot->base);
snapshot = malloc (sizeof (cairo_surface_snapshot_t));
if (unlikely (snapshot == NULL))
return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_FINISHED));
_cairo_surface_init (&snapshot->base,
&_cairo_surface_snapshot_backend,
NULL, /* device */
surface->content);
snapshot->base.type = surface->type;
snapshot->target = surface;
snapshot->clone = NULL;
status = _cairo_surface_copy_mime_data (&snapshot->base, surface);
if (unlikely (status)) {
cairo_surface_destroy (&snapshot->base);
return _cairo_surface_create_in_error (status);
}
snapshot->base.device_transform = surface->device_transform;
snapshot->base.device_transform_inverse = surface->device_transform_inverse;
cairo_surface_attach_snapshot (surface,
&snapshot->base,
_cairo_surface_snapshot_copy_on_write);
return &snapshot->base;
}
