Subversion Repositories Kolibri OS

/*

 * Copyright © 2006 Keith Packard

 * Copyright © 2007 Adrian Johnson

 *

 * This library is free software; you can redistribute it and/or

 * modify it either under the terms of the GNU Lesser General Public

 * License version 2.1 as published by the Free Software Foundation

 * (the "LGPL") or, at your option, under the terms of the Mozilla

 * Public License Version 1.1 (the "MPL"). If you do not alter this

 * notice, a recipient may use your version of this file under either

 * the MPL or the LGPL.

 *

 * You should have received a copy of the LGPL along with this library

 * in the file COPYING-LGPL-2.1; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA

 * You should have received a copy of the MPL along with this library

 * in the file COPYING-MPL-1.1

 *

 * The contents of this file are subject to the Mozilla Public License

 * Version 1.1 (the "License"); you may not use this file except in

 * compliance with the License. You may obtain a copy of the License at

 * http://www.mozilla.org/MPL/

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY

 * OF ANY KIND, either express or implied. See the LGPL or the MPL for

 * the specific language governing rights and limitations.

 *

 * The Original Code is the cairo graphics library.

 *

 * The Initial Developer of the Original Code is Keith Packard

 *

 * Contributor(s):

 *      Keith Packard 

 *      Adrian Johnson 

 */

#include "cairoint.h"

#include "cairo-analysis-surface-private.h"

#include "cairo-error-private.h"

#include "cairo-paginated-private.h"

#include "cairo-recording-surface-private.h"

#include "cairo-surface-subsurface-private.h"

#include "cairo-region-private.h"

typedef struct {

    cairo_surface_t base;

    cairo_surface_t *target;

    cairo_bool_t first_op;

    cairo_bool_t has_supported;

    cairo_bool_t has_unsupported;

    cairo_region_t supported_region;

    cairo_region_t fallback_region;

    cairo_box_t page_bbox;

    cairo_bool_t has_ctm;

    cairo_matrix_t ctm;

} cairo_analysis_surface_t;

cairo_int_status_t

_cairo_analysis_surface_merge_status (cairo_int_status_t status_a,

				      cairo_int_status_t status_b)

{

    /* fatal errors should be checked and propagated at source */

    assert (! _cairo_status_is_error (status_a));

    assert (! _cairo_status_is_error (status_b));

    /* return the most important status */

    if (status_a == CAIRO_INT_STATUS_UNSUPPORTED ||

	status_b == CAIRO_INT_STATUS_UNSUPPORTED)

	return CAIRO_INT_STATUS_UNSUPPORTED;

    if (status_a == CAIRO_INT_STATUS_IMAGE_FALLBACK ||

	status_b == CAIRO_INT_STATUS_IMAGE_FALLBACK)

	return CAIRO_INT_STATUS_IMAGE_FALLBACK;

    if (status_a == CAIRO_INT_STATUS_ANALYZE_RECORDING_SURFACE_PATTERN ||

	status_b == CAIRO_INT_STATUS_ANALYZE_RECORDING_SURFACE_PATTERN)

	return CAIRO_INT_STATUS_ANALYZE_RECORDING_SURFACE_PATTERN;

    if (status_a == CAIRO_INT_STATUS_FLATTEN_TRANSPARENCY ||

	status_b == CAIRO_INT_STATUS_FLATTEN_TRANSPARENCY)

	return CAIRO_INT_STATUS_FLATTEN_TRANSPARENCY;

    /* at this point we have checked all the valid internal codes, so... */

    assert (status_a == CAIRO_STATUS_SUCCESS &&

	    status_b == CAIRO_STATUS_SUCCESS);

    return CAIRO_STATUS_SUCCESS;

}

static cairo_int_status_t

_analyze_recording_surface_pattern (cairo_analysis_surface_t *surface,

				    const cairo_pattern_t    *pattern)

{

    const cairo_surface_pattern_t *surface_pattern;

    cairo_bool_t old_has_ctm;

    cairo_matrix_t old_ctm, p2d;

    cairo_status_t status;

    cairo_surface_t *source;

    assert (pattern->type == CAIRO_PATTERN_TYPE_SURFACE);

    surface_pattern = (const cairo_surface_pattern_t *) pattern;

    assert (surface_pattern->surface->type == CAIRO_SURFACE_TYPE_RECORDING);

    old_ctm = surface->ctm;

    old_has_ctm = surface->has_ctm;

    p2d = pattern->matrix;

    status = cairo_matrix_invert (&p2d);

    assert (status == CAIRO_STATUS_SUCCESS);

    cairo_matrix_multiply (&surface->ctm, &p2d, &surface->ctm);

    surface->has_ctm = ! _cairo_matrix_is_identity (&surface->ctm);

    source = surface_pattern->surface;

    if (source->backend->type == CAIRO_SURFACE_TYPE_SUBSURFACE) {

	cairo_surface_subsurface_t *sub = (cairo_surface_subsurface_t *) source;

	source = sub->target;

    }

    status = _cairo_recording_surface_replay_and_create_regions (source, &surface->base);

    surface->ctm = old_ctm;

    surface->has_ctm = old_has_ctm;

    return status;

}

static cairo_int_status_t

_add_operation (cairo_analysis_surface_t *surface,

		cairo_rectangle_int_t    *rect,

		cairo_int_status_t        backend_status)

{

    cairo_int_status_t status;

    cairo_box_t bbox;

    if (rect->width == 0 || rect->height == 0) {

	/* Even though the operation is not visible we must be careful

	 * to not allow unsupported operations to be replayed to the

	 * backend during CAIRO_PAGINATED_MODE_RENDER */

	if (backend_status == CAIRO_STATUS_SUCCESS ||

	    backend_status == CAIRO_INT_STATUS_FLATTEN_TRANSPARENCY)

	{

	    return CAIRO_STATUS_SUCCESS;

	}

	else

	{

	    return CAIRO_INT_STATUS_IMAGE_FALLBACK;

	}

    }

    _cairo_box_from_rectangle (&bbox, rect);

    if (surface->has_ctm) {

	int tx, ty;

	if (_cairo_matrix_is_integer_translation (&surface->ctm, &tx, &ty)) {

	    rect->x += tx;

	    rect->y += ty;

	} else {

	    _cairo_matrix_transform_bounding_box_fixed (&surface->ctm,

							&bbox, NULL);

	    if (bbox.p1.x == bbox.p2.x || bbox.p1.y == bbox.p2.y) {

		/* Even though the operation is not visible we must be

		 * careful to not allow unsupported operations to be

		 * replayed to the backend during

		 * CAIRO_PAGINATED_MODE_RENDER */

		if (backend_status == CAIRO_STATUS_SUCCESS ||

		    backend_status == CAIRO_INT_STATUS_FLATTEN_TRANSPARENCY)

		{

		    return CAIRO_STATUS_SUCCESS;

		}

		else

		{

		    return CAIRO_INT_STATUS_IMAGE_FALLBACK;

		}

	    }

	    _cairo_box_round_to_rectangle (&bbox, rect);

	}

    }

    if (surface->first_op) {

	surface->first_op = FALSE;

	surface->page_bbox = bbox;

    } else {

	if (bbox.p1.x < surface->page_bbox.p1.x)

	    surface->page_bbox.p1.x = bbox.p1.x;

	if (bbox.p1.y < surface->page_bbox.p1.y)

	    surface->page_bbox.p1.y = bbox.p1.y;

	if (bbox.p2.x > surface->page_bbox.p2.x)

	    surface->page_bbox.p2.x = bbox.p2.x;

	if (bbox.p2.y > surface->page_bbox.p2.y)

	    surface->page_bbox.p2.y = bbox.p2.y;

    }

    /* If the operation is completely enclosed within the fallback

     * region there is no benefit in emitting a native operation as

     * the fallback image will be painted on top.

     */

    if (cairo_region_contains_rectangle (&surface->fallback_region, rect) == CAIRO_REGION_OVERLAP_IN)

	return CAIRO_INT_STATUS_IMAGE_FALLBACK;

    if (backend_status == CAIRO_INT_STATUS_FLATTEN_TRANSPARENCY) {

	/* A status of CAIRO_INT_STATUS_FLATTEN_TRANSPARENCY indicates

	 * that the backend only supports this operation if the

	 * transparency removed. If the extents of this operation does

	 * not intersect any other native operation, the operation is

	 * natively supported and the backend will blend the

	 * transparency into the white background.

	 */

	if (cairo_region_contains_rectangle (&surface->supported_region, rect) == CAIRO_REGION_OVERLAP_OUT)

	    backend_status = CAIRO_STATUS_SUCCESS;

    }

    if (backend_status == CAIRO_STATUS_SUCCESS) {

	/* Add the operation to the supported region. Operations in

	 * this region will be emitted as native operations.

	 */

	surface->has_supported = TRUE;

	return cairo_region_union_rectangle (&surface->supported_region, rect);

    }

    /* Add the operation to the unsupported region. This region will

     * be painted as an image after all native operations have been

     * emitted.

     */

    surface->has_unsupported = TRUE;

    status = cairo_region_union_rectangle (&surface->fallback_region, rect);

    /* The status CAIRO_INT_STATUS_IMAGE_FALLBACK is used to indicate

     * unsupported operations to the recording surface as using

     * CAIRO_INT_STATUS_UNSUPPORTED would cause cairo-surface to

     * invoke the cairo-surface-fallback path then return

     * CAIRO_STATUS_SUCCESS.

     */

    if (status == CAIRO_STATUS_SUCCESS)

	return CAIRO_INT_STATUS_IMAGE_FALLBACK;

    else

	return status;

}

static cairo_status_t

_cairo_analysis_surface_finish (void *abstract_surface)

{

    cairo_analysis_surface_t	*surface = (cairo_analysis_surface_t *) abstract_surface;

    _cairo_region_fini (&surface->supported_region);

    _cairo_region_fini (&surface->fallback_region);

    cairo_surface_destroy (surface->target);

    return CAIRO_STATUS_SUCCESS;

}

static cairo_bool_t

_cairo_analysis_surface_get_extents (void			*abstract_surface,

				     cairo_rectangle_int_t	*rectangle)

{

    cairo_analysis_surface_t *surface = abstract_surface;

    return _cairo_surface_get_extents (surface->target, rectangle);

}

static void

_rectangle_intersect_clip (cairo_rectangle_int_t *extents, cairo_clip_t *clip)

{

    const cairo_rectangle_int_t *clip_extents;

    cairo_bool_t is_empty;

    clip_extents = NULL;

    if (clip != NULL)

	clip_extents = _cairo_clip_get_extents (clip);

    if (clip_extents != NULL)

	is_empty = _cairo_rectangle_intersect (extents, clip_extents);

}

static void

_cairo_analysis_surface_operation_extents (cairo_analysis_surface_t *surface,

					   cairo_operator_t op,

					   const cairo_pattern_t *source,

					   cairo_clip_t *clip,

					   cairo_rectangle_int_t *extents)

{

    cairo_bool_t is_empty;

    is_empty = _cairo_surface_get_extents (&surface->base, extents);

    if (_cairo_operator_bounded_by_source (op)) {

	cairo_rectangle_int_t source_extents;

	_cairo_pattern_get_extents (source, &source_extents);

	is_empty = _cairo_rectangle_intersect (extents, &source_extents);

    }

    _rectangle_intersect_clip (extents, clip);

}

static cairo_int_status_t

_cairo_analysis_surface_paint (void			*abstract_surface,

			       cairo_operator_t		op,

			       const cairo_pattern_t	*source,

			       cairo_clip_t		*clip)

{

    cairo_analysis_surface_t *surface = abstract_surface;

    cairo_status_t	     backend_status;

    cairo_rectangle_int_t  extents;

    if (surface->target->backend->paint == NULL) {

	backend_status = CAIRO_INT_STATUS_UNSUPPORTED;

    } else {

	backend_status =

	    surface->target->backend->paint (surface->target,

					     op, source, clip);

	if (_cairo_status_is_error (backend_status))

	    return backend_status;

    }

    if (backend_status == CAIRO_INT_STATUS_ANALYZE_RECORDING_SURFACE_PATTERN)

	backend_status = _analyze_recording_surface_pattern (surface, source);

    _cairo_analysis_surface_operation_extents (surface,

					       op, source, clip,

					       &extents);

    return _add_operation (surface, &extents, backend_status);

}

static cairo_int_status_t

_cairo_analysis_surface_mask (void			*abstract_surface,

			      cairo_operator_t		 op,

			      const cairo_pattern_t	*source,

			      const cairo_pattern_t	*mask,

			      cairo_clip_t		*clip)

{

    cairo_analysis_surface_t *surface = abstract_surface;

    cairo_int_status_t	      backend_status;

    cairo_rectangle_int_t   extents;

    cairo_bool_t is_empty;

    if (surface->target->backend->mask == NULL) {

	backend_status = CAIRO_INT_STATUS_UNSUPPORTED;

    } else {

	backend_status =

	    surface->target->backend->mask (surface->target,

					    op, source, mask, clip);

	if (_cairo_status_is_error (backend_status))

	    return backend_status;

    }

    if (backend_status == CAIRO_INT_STATUS_ANALYZE_RECORDING_SURFACE_PATTERN) {

	cairo_int_status_t backend_source_status = CAIRO_STATUS_SUCCESS;

	cairo_int_status_t backend_mask_status = CAIRO_STATUS_SUCCESS;

	if (source->type == CAIRO_PATTERN_TYPE_SURFACE) {

	    const cairo_surface_pattern_t *surface_pattern = (const cairo_surface_pattern_t *) source;

	    if (_cairo_surface_is_recording (surface_pattern->surface)) {

		backend_source_status =

		    _analyze_recording_surface_pattern (surface, source);

		if (_cairo_status_is_error (backend_source_status))

		    return backend_source_status;

	    }

	}

	if (mask->type == CAIRO_PATTERN_TYPE_SURFACE) {

	    cairo_surface_pattern_t *surface_pattern = (cairo_surface_pattern_t *) mask;

	    if (_cairo_surface_is_recording (surface_pattern->surface)) {

		backend_mask_status =

		    _analyze_recording_surface_pattern (surface, mask);

		if (_cairo_status_is_error (backend_mask_status))

		    return backend_mask_status;

	    }

	}

	backend_status =

	    _cairo_analysis_surface_merge_status (backend_source_status,

						  backend_mask_status);

    }

    _cairo_analysis_surface_operation_extents (surface,

					       op, source, clip,

					       &extents);

    if (_cairo_operator_bounded_by_mask (op)) {

	cairo_rectangle_int_t mask_extents;

	_cairo_pattern_get_extents (mask, &mask_extents);

	is_empty = _cairo_rectangle_intersect (&extents, &mask_extents);

    }

    return _add_operation (surface, &extents, backend_status);

}

static cairo_int_status_t

_cairo_analysis_surface_stroke (void			*abstract_surface,

				cairo_operator_t	 op,

				const cairo_pattern_t	*source,

				cairo_path_fixed_t	*path,

				const cairo_stroke_style_t	*style,

				const cairo_matrix_t		*ctm,

				const cairo_matrix_t		*ctm_inverse,

				double			 tolerance,

				cairo_antialias_t	 antialias,

				cairo_clip_t		*clip)

{

    cairo_analysis_surface_t *surface = abstract_surface;

    cairo_status_t	     backend_status;

    cairo_rectangle_int_t    extents;

    cairo_bool_t             is_empty;

    if (surface->target->backend->stroke == NULL) {

	backend_status = CAIRO_INT_STATUS_UNSUPPORTED;

    } else {

	backend_status =

	    surface->target->backend->stroke (surface->target, op,

					      source, path, style,

					      ctm, ctm_inverse,

					      tolerance, antialias,

					      clip);

	if (_cairo_status_is_error (backend_status))

	    return backend_status;

    }

    if (backend_status == CAIRO_INT_STATUS_ANALYZE_RECORDING_SURFACE_PATTERN)

	backend_status = _analyze_recording_surface_pattern (surface, source);

    _cairo_analysis_surface_operation_extents (surface,

					       op, source, clip,

					       &extents);

    if (_cairo_operator_bounded_by_mask (op)) {

	cairo_rectangle_int_t mask_extents;

	cairo_status_t status;

	status = _cairo_path_fixed_stroke_extents (path, style,

						   ctm, ctm_inverse,

						   tolerance,

						   &mask_extents);

	if (unlikely (status))

	    return status;

	is_empty = _cairo_rectangle_intersect (&extents, &mask_extents);

    }

    return _add_operation (surface, &extents, backend_status);

}

static cairo_int_status_t

_cairo_analysis_surface_fill (void			*abstract_surface,

			      cairo_operator_t		 op,

			      const cairo_pattern_t	*source,

			      cairo_path_fixed_t	*path,

			      cairo_fill_rule_t		 fill_rule,

			      double			 tolerance,

			      cairo_antialias_t		 antialias,

			      cairo_clip_t		*clip)

{

    cairo_analysis_surface_t *surface = abstract_surface;

    cairo_status_t	     backend_status;

    cairo_rectangle_int_t    extents;

    cairo_bool_t             is_empty;

    if (surface->target->backend->fill == NULL) {

	backend_status = CAIRO_INT_STATUS_UNSUPPORTED;

    } else {

	backend_status =

	    surface->target->backend->fill (surface->target, op,

					    source, path, fill_rule,

					    tolerance, antialias,

					    clip);

	if (_cairo_status_is_error (backend_status))

	    return backend_status;

    }

    if (backend_status == CAIRO_INT_STATUS_ANALYZE_RECORDING_SURFACE_PATTERN)

	backend_status = _analyze_recording_surface_pattern (surface, source);

    _cairo_analysis_surface_operation_extents (surface,

					       op, source, clip,

					       &extents);

    if (_cairo_operator_bounded_by_mask (op)) {

	cairo_rectangle_int_t mask_extents;

	_cairo_path_fixed_fill_extents (path, fill_rule, tolerance,

					&mask_extents);

	is_empty = _cairo_rectangle_intersect (&extents, &mask_extents);

    }

    return _add_operation (surface, &extents, backend_status);

}

static cairo_int_status_t

_cairo_analysis_surface_show_glyphs (void		  *abstract_surface,

				     cairo_operator_t	   op,

				     const cairo_pattern_t *source,

				     cairo_glyph_t	  *glyphs,

				     int		   num_glyphs,

				     cairo_scaled_font_t  *scaled_font,

				     cairo_clip_t         *clip,

				     int                  *remaining_glyphs)

{

    cairo_analysis_surface_t *surface = abstract_surface;

    cairo_status_t	     status, backend_status;

    cairo_rectangle_int_t    extents, glyph_extents;

    cairo_bool_t             is_empty;

    /* Adapted from _cairo_surface_show_glyphs */

    if (surface->target->backend->show_glyphs != NULL) {

	backend_status =

	    surface->target->backend->show_glyphs (surface->target, op,

						   source,

						   glyphs, num_glyphs,

						   scaled_font,

						   clip,

						   remaining_glyphs);

	if (_cairo_status_is_error (backend_status))

	    return backend_status;

    }

    else if (surface->target->backend->show_text_glyphs != NULL)

    {

	backend_status =

	    surface->target->backend->show_text_glyphs (surface->target, op,

							source,

							NULL, 0,

							glyphs, num_glyphs,

							NULL, 0,

							FALSE,

							scaled_font,

							clip);

	if (_cairo_status_is_error (backend_status))

	    return backend_status;

    }

    else

    {

	backend_status = CAIRO_INT_STATUS_UNSUPPORTED;

    }

    if (backend_status == CAIRO_INT_STATUS_ANALYZE_RECORDING_SURFACE_PATTERN)

	backend_status = _analyze_recording_surface_pattern (surface, source);

    _cairo_analysis_surface_operation_extents (surface,

					       op, source, clip,

					       &extents);

    if (_cairo_operator_bounded_by_mask (op)) {

	status = _cairo_scaled_font_glyph_device_extents (scaled_font,

							  glyphs,

							  num_glyphs,

							  &glyph_extents,

							  NULL);

	if (unlikely (status))

	    return status;

	is_empty = _cairo_rectangle_intersect (&extents, &glyph_extents);

    }

    return _add_operation (surface, &extents, backend_status);

}

static cairo_bool_t

_cairo_analysis_surface_has_show_text_glyphs (void *abstract_surface)

{

    cairo_analysis_surface_t *surface = abstract_surface;

    return cairo_surface_has_show_text_glyphs (surface->target);

}

static cairo_int_status_t

_cairo_analysis_surface_show_text_glyphs (void			    *abstract_surface,

					  cairo_operator_t	     op,

					  const cairo_pattern_t	    *source,

					  const char		    *utf8,

					  int			     utf8_len,

					  cairo_glyph_t		    *glyphs,

					  int			     num_glyphs,

					  const cairo_text_cluster_t *clusters,

					  int			     num_clusters,

					  cairo_text_cluster_flags_t cluster_flags,

					  cairo_scaled_font_t	    *scaled_font,

					  cairo_clip_t		    *clip)

{

    cairo_analysis_surface_t *surface = abstract_surface;

    cairo_status_t	     status, backend_status;

    cairo_rectangle_int_t    extents, glyph_extents;

    cairo_bool_t             is_empty;

    /* Adapted from _cairo_surface_show_glyphs */

    backend_status = CAIRO_INT_STATUS_UNSUPPORTED;

    if (surface->target->backend->show_text_glyphs != NULL) {

	backend_status =

	    surface->target->backend->show_text_glyphs (surface->target, op,

							source,

							utf8, utf8_len,

							glyphs, num_glyphs,

							clusters, num_clusters,

							cluster_flags,

							scaled_font,

							clip);

	if (_cairo_status_is_error (backend_status))

	    return backend_status;

    }

    if (backend_status == CAIRO_INT_STATUS_UNSUPPORTED &&

	surface->target->backend->show_glyphs != NULL)

    {

	int remaining_glyphs = num_glyphs;

	backend_status =

	    surface->target->backend->show_glyphs (surface->target, op,

						   source,

						   glyphs, num_glyphs,

						   scaled_font,

						   clip,

						   &remaining_glyphs);

	if (_cairo_status_is_error (backend_status))

	    return backend_status;

	glyphs += num_glyphs - remaining_glyphs;

	num_glyphs = remaining_glyphs;

	if (remaining_glyphs == 0)

	    backend_status = CAIRO_STATUS_SUCCESS;

    }

    if (backend_status == CAIRO_INT_STATUS_ANALYZE_RECORDING_SURFACE_PATTERN)

	backend_status = _analyze_recording_surface_pattern (surface, source);

    _cairo_analysis_surface_operation_extents (surface,

					       op, source, clip,

					       &extents);

    if (_cairo_operator_bounded_by_mask (op)) {

	status = _cairo_scaled_font_glyph_device_extents (scaled_font,

							  glyphs,

							  num_glyphs,

							  &glyph_extents,

							  NULL);

	if (unlikely (status))

	    return status;

	is_empty = _cairo_rectangle_intersect (&extents, &glyph_extents);

    }

    return _add_operation (surface, &extents, backend_status);

}

static const cairo_surface_backend_t cairo_analysis_surface_backend = {

    CAIRO_INTERNAL_SURFACE_TYPE_ANALYSIS,

    NULL, /* create_similar */

    _cairo_analysis_surface_finish,

    NULL, /* acquire_source_image */

    NULL, /* release_source_image */

    NULL, /* acquire_dest_image */

    NULL, /* release_dest_image */

    NULL, /* clone_similar */

    NULL, /* composite */

    NULL, /* fill_rectangles */

    NULL, /* composite_trapezoids */

    NULL, /* create_span_renderer */

    NULL, /* check_span_renderer */

    NULL, /* copy_page */

    NULL, /* show_page */

    _cairo_analysis_surface_get_extents,

    NULL, /* old_show_glyphs */

    NULL, /* get_font_options */

    NULL, /* flush */

    NULL, /* mark_dirty_rectangle */

    NULL, /* scaled_font_fini */

    NULL, /* scaled_glyph_fini */

    _cairo_analysis_surface_paint,

    _cairo_analysis_surface_mask,

    _cairo_analysis_surface_stroke,

    _cairo_analysis_surface_fill,

    _cairo_analysis_surface_show_glyphs,

    NULL, /* snapshot */

    NULL, /* is_similar */

    NULL, /* fill_stroke */

    NULL, /* create_solid_pattern_surface */

    NULL, /* can_repaint_solid_pattern_surface */

    _cairo_analysis_surface_has_show_text_glyphs,

    _cairo_analysis_surface_show_text_glyphs

};

cairo_surface_t *

_cairo_analysis_surface_create (cairo_surface_t		*target)

{

    cairo_analysis_surface_t *surface;

    cairo_status_t status;

    status = target->status;

    if (unlikely (status))

	return _cairo_surface_create_in_error (status);

    surface = malloc (sizeof (cairo_analysis_surface_t));

    if (unlikely (surface == NULL))

	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));

    /* I believe the content type here is truly arbitrary. I'm quite

     * sure nothing will ever use this value. */

    _cairo_surface_init (&surface->base,

			 &cairo_analysis_surface_backend,

			 NULL, /* device */

			 CAIRO_CONTENT_COLOR_ALPHA);

    cairo_matrix_init_identity (&surface->ctm);

    surface->has_ctm = FALSE;

    surface->target = cairo_surface_reference (target);

    surface->first_op  = TRUE;

    surface->has_supported = FALSE;

    surface->has_unsupported = FALSE;

    _cairo_region_init (&surface->supported_region);

    _cairo_region_init (&surface->fallback_region);

    surface->page_bbox.p1.x = 0;

    surface->page_bbox.p1.y = 0;

    surface->page_bbox.p2.x = 0;

    surface->page_bbox.p2.y = 0;

    return &surface->base;

}

void

_cairo_analysis_surface_set_ctm (cairo_surface_t *abstract_surface,

				 const cairo_matrix_t  *ctm)

{

    cairo_analysis_surface_t	*surface;

    if (abstract_surface->status)

	return;

    surface = (cairo_analysis_surface_t *) abstract_surface;

    surface->ctm = *ctm;

    surface->has_ctm = ! _cairo_matrix_is_identity (&surface->ctm);

}

void

_cairo_analysis_surface_get_ctm (cairo_surface_t *abstract_surface,

				 cairo_matrix_t  *ctm)

{

    cairo_analysis_surface_t	*surface = (cairo_analysis_surface_t *) abstract_surface;

    *ctm = surface->ctm;

}

cairo_region_t *

_cairo_analysis_surface_get_supported (cairo_surface_t *abstract_surface)

{

    cairo_analysis_surface_t	*surface = (cairo_analysis_surface_t *) abstract_surface;

    return &surface->supported_region;

}

cairo_region_t *

_cairo_analysis_surface_get_unsupported (cairo_surface_t *abstract_surface)

{

    cairo_analysis_surface_t	*surface = (cairo_analysis_surface_t *) abstract_surface;

    return &surface->fallback_region;

}

cairo_bool_t

_cairo_analysis_surface_has_supported (cairo_surface_t *abstract_surface)

{

    cairo_analysis_surface_t	*surface = (cairo_analysis_surface_t *) abstract_surface;

    return surface->has_supported;

}

cairo_bool_t

_cairo_analysis_surface_has_unsupported (cairo_surface_t *abstract_surface)

{

    cairo_analysis_surface_t	*surface = (cairo_analysis_surface_t *) abstract_surface;

    return surface->has_unsupported;

}

void

_cairo_analysis_surface_get_bounding_box (cairo_surface_t *abstract_surface,

					  cairo_box_t     *bbox)

{

    cairo_analysis_surface_t	*surface = (cairo_analysis_surface_t *) abstract_surface;

    *bbox = surface->page_bbox;

}

/* null surface type: a surface that does nothing (has no side effects, yay!) */

static cairo_int_status_t

_return_success (void)

{

    return CAIRO_STATUS_SUCCESS;

}

/* These typedefs are just to silence the compiler... */

typedef cairo_int_status_t

(*_paint_func)			(void			*surface,

			         cairo_operator_t	 op,

				 const cairo_pattern_t	*source,

				 cairo_clip_t		*clip);

typedef cairo_int_status_t

(*_mask_func)			(void			*surface,

			         cairo_operator_t	 op,

				 const cairo_pattern_t	*source,

				 const cairo_pattern_t	*mask,

				 cairo_clip_t		*clip);

typedef cairo_int_status_t

(*_stroke_func)			(void			*surface,

			         cairo_operator_t	 op,

				 const cairo_pattern_t	*source,

				 cairo_path_fixed_t	*path,

				 const cairo_stroke_style_t	*style,

				 const cairo_matrix_t		*ctm,

				 const cairo_matrix_t		*ctm_inverse,

				 double			 tolerance,

				 cairo_antialias_t	 antialias,

				 cairo_clip_t		*clip);

typedef cairo_int_status_t

(*_fill_func)			(void			*surface,

			         cairo_operator_t	 op,

				 const cairo_pattern_t	*source,

				 cairo_path_fixed_t	*path,

				 cairo_fill_rule_t	 fill_rule,

				 double			 tolerance,

				 cairo_antialias_t	 antialias,

				 cairo_clip_t		*clip);

typedef cairo_int_status_t

(*_show_glyphs_func)		(void			*surface,

			         cairo_operator_t	 op,

				 const cairo_pattern_t	*source,

				 cairo_glyph_t		*glyphs,

				 int			 num_glyphs,

				 cairo_scaled_font_t	*scaled_font,

				 cairo_clip_t		*clip,

				 int			*remaining_glyphs);

static const cairo_surface_backend_t cairo_null_surface_backend = {

    CAIRO_INTERNAL_SURFACE_TYPE_NULL,

    NULL, /* create_similar */

    NULL, /* finish */

    NULL, /* acquire_source_image */

    NULL, /* release_source_image */

    NULL, /* acquire_dest_image */

    NULL, /* release_dest_image */

    NULL, /* clone_similar */

    NULL, /* composite */

    NULL, /* fill_rectangles */

    NULL, /* composite_trapezoids */

    NULL, /* create_span_renderer */

    NULL, /* check_span_renderer */

    NULL, /* copy_page */

    NULL, /* show_page */

    NULL, /* get_extents */

    NULL, /* old_show_glyphs */

    NULL, /* get_font_options */

    NULL, /* flush */

    NULL, /* mark_dirty_rectangle */

    NULL, /* scaled_font_fini */

    NULL, /* scaled_glyph_fini */

    (_paint_func) _return_success,	    /* paint */

    (_mask_func) _return_success,	    /* mask */

    (_stroke_func) _return_success,	    /* stroke */

    (_fill_func) _return_success,	    /* fill */

    (_show_glyphs_func) _return_success,    /* show_glyphs */

    NULL, /* snapshot */

    NULL, /* is_similar */

    NULL, /* fill_stroke */

    NULL, /* create_solid_pattern_surface */

    NULL, /* can_repaint_solid_pattern_surface */

    NULL, /* has_show_text_glyphs */

    NULL  /* show_text_glyphs */

};

cairo_surface_t *

_cairo_null_surface_create (cairo_content_t content)

{

    cairo_surface_t *surface;

    surface = malloc (sizeof (cairo_surface_t));

    if (unlikely (surface == NULL)) {

	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));

    }

    _cairo_surface_init (surface,

			 &cairo_null_surface_backend,

			 NULL, /* device */

			 content);

    return surface;

}