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cairo/src/cairo-win32-surface.c

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/* Cairo - a vector graphics library with display and print output
*
* Copyright © 2005 Red Hat, Inc.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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 Red Hat, Inc.
*
* Contributor(s):
* Owen Taylor <otaylor@redhat.com>
*/
#include <stdio.h>
#include "cairoint.h"
#include "cairo-win32-private.h"
static const cairo_surface_backend_t cairo_win32_surface_backend;
/**
* _cairo_win32_print_gdi_error:
* @context: context string to display along with the error
*
* Helper function to dump out a human readable form of the
* current error code.
*
* Return value: A cairo status code for the error code
**/
cairo_status_t
_cairo_win32_print_gdi_error (const char *context)
{
void *lpMsgBuf;
DWORD last_error = GetLastError ();
if (!FormatMessageA (FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM,
NULL,
last_error,
MAKELANGID (LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &lpMsgBuf,
0, NULL)) {
fprintf (stderr, "%s: Unknown GDI error", context);
} else {
fprintf (stderr, "%s: %s", context, (char *)lpMsgBuf);
LocalFree (lpMsgBuf);
}
/* We should switch off of last_status, but we'd either return
* CAIRO_STATUS_NO_MEMORY or CAIRO_STATUS_UNKNOWN_ERROR and there
* is no CAIRO_STATUS_UNKNOWN_ERROR.
*/
return CAIRO_STATUS_NO_MEMORY;
}
static cairo_status_t
_create_dc_and_bitmap (cairo_win32_surface_t *surface,
HDC original_dc,
cairo_format_t format,
int width,
int height,
char **bits_out,
int *rowstride_out)
{
cairo_status_t status;
BITMAPINFO *bitmap_info = NULL;
struct {
BITMAPINFOHEADER bmiHeader;
RGBQUAD bmiColors[2];
} bmi_stack;
void *bits;
int num_palette = 0; /* Quiet GCC */
int i;
surface->dc = NULL;
surface->bitmap = NULL;
switch (format) {
case CAIRO_FORMAT_ARGB32:
case CAIRO_FORMAT_RGB24:
num_palette = 0;
break;
case CAIRO_FORMAT_A8:
num_palette = 256;
break;
case CAIRO_FORMAT_A1:
num_palette = 2;
break;
}
if (num_palette > 2) {
bitmap_info = malloc (sizeof (BITMAPINFOHEADER) + num_palette * sizeof (RGBQUAD));
if (!bitmap_info)
return CAIRO_STATUS_NO_MEMORY;
} else {
bitmap_info = (BITMAPINFO *)&bmi_stack;
}
bitmap_info->bmiHeader.biSize = sizeof (BITMAPINFOHEADER);
bitmap_info->bmiHeader.biWidth = width;
bitmap_info->bmiHeader.biHeight = - height; /* top-down */
bitmap_info->bmiHeader.biSizeImage = 0;
bitmap_info->bmiHeader.biXPelsPerMeter = 72. / 0.0254; /* unused here */
bitmap_info->bmiHeader.biYPelsPerMeter = 72. / 0.0254; /* unused here */
bitmap_info->bmiHeader.biPlanes = 1;
switch (format) {
case CAIRO_FORMAT_ARGB32:
case CAIRO_FORMAT_RGB24:
bitmap_info->bmiHeader.biBitCount = 32;
bitmap_info->bmiHeader.biCompression = BI_RGB;
bitmap_info->bmiHeader.biClrUsed = 0; /* unused */
bitmap_info->bmiHeader.biClrImportant = 0;
break;
case CAIRO_FORMAT_A8:
bitmap_info->bmiHeader.biBitCount = 8;
bitmap_info->bmiHeader.biCompression = BI_RGB;
bitmap_info->bmiHeader.biClrUsed = 256;
bitmap_info->bmiHeader.biClrImportant = 0;
for (i = 0; i < 256; i++) {
bitmap_info->bmiColors[i].rgbBlue = i;
bitmap_info->bmiColors[i].rgbGreen = i;
bitmap_info->bmiColors[i].rgbRed = i;
bitmap_info->bmiColors[i].rgbReserved = 0;
}
break;
case CAIRO_FORMAT_A1:
bitmap_info->bmiHeader.biBitCount = 1;
bitmap_info->bmiHeader.biCompression = BI_RGB;
bitmap_info->bmiHeader.biClrUsed = 2;
bitmap_info->bmiHeader.biClrImportant = 0;
for (i = 0; i < 2; i++) {
bitmap_info->bmiColors[i].rgbBlue = i * 255;
bitmap_info->bmiColors[i].rgbGreen = i * 255;
bitmap_info->bmiColors[i].rgbRed = i * 255;
bitmap_info->bmiColors[i].rgbReserved = 0;
break;
}
}
surface->dc = CreateCompatibleDC (original_dc);
if (!surface->dc)
goto FAIL;
surface->bitmap = CreateDIBSection (surface->dc,
bitmap_info,
DIB_RGB_COLORS,
&bits,
NULL, 0);
if (!surface->bitmap)
goto FAIL;
surface->saved_dc_bitmap = SelectObject (surface->dc,
surface->bitmap);
if (!surface->saved_dc_bitmap)
goto FAIL;
if (bitmap_info && num_palette > 2)
free (bitmap_info);
if (bits_out)
*bits_out = bits;
if (rowstride_out) {
/* Windows bitmaps are padded to 16-bit (word) boundaries */
switch (format) {
case CAIRO_FORMAT_ARGB32:
case CAIRO_FORMAT_RGB24:
*rowstride_out = 4 * width;
break;
case CAIRO_FORMAT_A8:
*rowstride_out = (width + 1) & -2;
break;
case CAIRO_FORMAT_A1:
*rowstride_out = ((width + 15) & -16) / 8;
break;
}
}
return CAIRO_STATUS_SUCCESS;
FAIL:
status = _cairo_win32_print_gdi_error ("_create_dc_and_bitmap");
if (bitmap_info && num_palette > 2)
free (bitmap_info);
if (surface->saved_dc_bitmap) {
SelectObject (surface->dc, surface->saved_dc_bitmap);
surface->saved_dc_bitmap = NULL;
}
if (surface->bitmap) {
DeleteObject (surface->bitmap);
surface->bitmap = NULL;
}
if (surface->dc) {
DeleteDC (surface->dc);
surface->dc = NULL;
}
return status;
}
static cairo_surface_t *
_cairo_win32_surface_create_for_dc (HDC original_dc,
cairo_format_t format,
int drawable,
int width,
int height)
{
cairo_win32_surface_t *surface;
char *bits;
int rowstride;
surface = malloc (sizeof (cairo_win32_surface_t));
if (!surface)
return NULL;
if (_create_dc_and_bitmap (surface, original_dc, format,
width, height,
&bits, &rowstride) != CAIRO_STATUS_SUCCESS)
goto FAIL;
surface->image = cairo_image_surface_create_for_data (bits, format,
width, height, rowstride);
if (!surface->image)
goto FAIL;
surface->format = format;
surface->clip_rect.x = 0;
surface->clip_rect.y = 0;
surface->clip_rect.width = width;
surface->clip_rect.height = height;
surface->set_clip = 0;
surface->saved_clip = NULL;
_cairo_surface_init (&surface->base, &cairo_win32_surface_backend);
return (cairo_surface_t *)surface;
FAIL:
if (surface->bitmap) {
SelectObject (surface->dc, surface->saved_dc_bitmap);
DeleteObject (surface->bitmap);
DeleteDC (surface->dc);
}
if (surface)
free (surface);
return NULL;
}
static cairo_surface_t *
_cairo_win32_surface_create_similar (void *abstract_src,
cairo_format_t format,
int drawable,
int width,
int height)
{
cairo_win32_surface_t *src = abstract_src;
return _cairo_win32_surface_create_for_dc (src->dc, format, drawable,
width, height);
}
/**
* _cairo_win32_surface_create_dib:
* @format: format of pixels in the surface to create
* @width: width of the surface, in pixels
* @height: height of the surface, in pixels
*
* Creates a device-independent-bitmap surface not associated with
* any particular existing surface or device context. The created
* bitmap will be unititialized.
*
* Return value: the newly created surface, or %NULL if it couldn't
* be created (probably because of lack of memory)
**/
cairo_surface_t *
_cairo_win32_surface_create_dib (cairo_format_t format,
int width,
int height)
{
return _cairo_win32_surface_create_for_dc (NULL, format, TRUE,
width, height);
}
static cairo_status_t
_cairo_win32_surface_finish (void *abstract_surface)
{
cairo_win32_surface_t *surface = abstract_surface;
if (surface->image)
cairo_surface_destroy (surface->image);
if (surface->saved_clip)
DeleteObject (surface->saved_clip);
/* If we created the Bitmap and DC, destroy them */
if (surface->bitmap) {
SelectObject (surface->dc, surface->saved_dc_bitmap);
DeleteObject (surface->bitmap);
DeleteDC (surface->dc);
}
return CAIRO_STATUS_SUCCESS;
}
static cairo_status_t
_cairo_win32_surface_get_subimage (cairo_win32_surface_t *surface,
int x,
int y,
int width,
int height,
cairo_win32_surface_t **local_out)
{
cairo_win32_surface_t *local;
cairo_status_t status;
local =
(cairo_win32_surface_t *) _cairo_win32_surface_create_similar (surface,
surface->format,
0,
width, height);
if (!local)
return CAIRO_STATUS_NO_MEMORY;
if (!BitBlt (local->dc,
0, 0,
width, height,
surface->dc,
x, y,
SRCCOPY))
goto FAIL;
*local_out = local;
return CAIRO_STATUS_SUCCESS;
FAIL:
status = _cairo_win32_print_gdi_error ("_cairo_win32_surface_get_subimage");
if (local)
cairo_surface_destroy (&local->base);
return status;
}
static cairo_status_t
_cairo_win32_surface_acquire_source_image (void *abstract_surface,
cairo_image_surface_t **image_out,
void **image_extra)
{
cairo_win32_surface_t *surface = abstract_surface;
cairo_win32_surface_t *local = NULL;
cairo_status_t status;
if (surface->image) {
*image_out = (cairo_image_surface_t *)surface->image;
*image_extra = NULL;
return CAIRO_STATUS_SUCCESS;
}
status = _cairo_win32_surface_get_subimage (abstract_surface, 0, 0,
surface->clip_rect.width,
surface->clip_rect.height, &local);
if (CAIRO_OK (status)) {
cairo_surface_set_filter (&local->base, surface->base.filter);
cairo_surface_set_matrix (&local->base, &surface->base.matrix);
cairo_surface_set_repeat (&local->base, surface->base.repeat);
*image_out = (cairo_image_surface_t *)local->image;
*image_extra = local;
}
return status;
}
static void
_cairo_win32_surface_release_source_image (void *abstract_surface,
cairo_image_surface_t *image,
void *image_extra)
{
cairo_win32_surface_t *local = image_extra;
if (local)
cairo_surface_destroy ((cairo_surface_t *)local);
}
static cairo_status_t
_cairo_win32_surface_acquire_dest_image (void *abstract_surface,
cairo_rectangle_t *interest_rect,
cairo_image_surface_t **image_out,
cairo_rectangle_t *image_rect,
void **image_extra)
{
cairo_win32_surface_t *surface = abstract_surface;
cairo_win32_surface_t *local = NULL;
cairo_status_t status;
RECT clip_box;
int x1, y1, x2, y2;
if (surface->image) {
image_rect->x = 0;
image_rect->y = 0;
image_rect->width = surface->clip_rect.width;
image_rect->height = surface->clip_rect.height;
*image_out = (cairo_image_surface_t *)surface->image;
*image_extra = NULL;
return CAIRO_STATUS_SUCCESS;
}
if (GetClipBox (surface->dc, &clip_box) == ERROR)
return _cairo_win32_print_gdi_error ("_cairo_win3_surface_acquire_dest_image");
x1 = clip_box.left;
x2 = clip_box.right;
y1 = clip_box.top;
y2 = clip_box.bottom;
if (interest_rect->x > x1)
x1 = interest_rect->x;
if (interest_rect->y > y1)
y1 = interest_rect->y;
if (interest_rect->x + interest_rect->width < x2)
x2 = interest_rect->x + interest_rect->width;
if (interest_rect->y + interest_rect->height < y2)
y2 = interest_rect->y + interest_rect->height;
if (x1 >= x2 || y1 >= y2) {
*image_out = NULL;
*image_extra = NULL;
return CAIRO_STATUS_SUCCESS;
}
status = _cairo_win32_surface_get_subimage (abstract_surface,
x1, y1, x2 - x1, y2 - y1,
&local);
if (CAIRO_OK (status)) {
*image_out = (cairo_image_surface_t *)local->image;
*image_extra = local;
image_rect->x = x1;
image_rect->y = y1;
image_rect->width = x2 - x1;
image_rect->height = y2 - y1;
}
return status;
}
static void
_cairo_win32_surface_release_dest_image (void *abstract_surface,
cairo_rectangle_t *interest_rect,
cairo_image_surface_t *image,
cairo_rectangle_t *image_rect,
void *image_extra)
{
cairo_win32_surface_t *surface = abstract_surface;
cairo_win32_surface_t *local = image_extra;
if (!local)
return;
if (!BitBlt (surface->dc,
image_rect->x, image_rect->y,
image_rect->width, image_rect->height,
local->dc,
0, 0,
SRCCOPY))
_cairo_win32_print_gdi_error ("_cairo_win32_surface_release_dest_image");
cairo_surface_destroy ((cairo_surface_t *)local);
}
static cairo_int_status_t
_cairo_win32_surface_composite (cairo_operator_t operator,
cairo_pattern_t *pattern,
cairo_pattern_t *mask_pattern,
void *abstract_dst,
int src_x,
int src_y,
int mask_x,
int mask_y,
int dst_x,
int dst_y,
unsigned int width,
unsigned int height)
{
cairo_win32_surface_t *dst = abstract_dst;
cairo_win32_surface_t *src;
cairo_surface_pattern_t *src_surface_pattern;
int alpha;
int integer_transform;
int itx, ity;
if (pattern->type != CAIRO_PATTERN_SURFACE ||
pattern->extend != CAIRO_EXTEND_NONE)
return CAIRO_INT_STATUS_UNSUPPORTED;
if (mask_pattern) {
/* FIXME: When we fully support RENDER style 4-channel
* masks we need to check r/g/b != 1.0.
*/
if (mask_pattern->type != CAIRO_PATTERN_SOLID)
return CAIRO_INT_STATUS_UNSUPPORTED;
alpha = (int)(0xffff * pattern->alpha * mask_pattern->alpha) >> 8;
} else {
alpha = (int)(0xffff * pattern->alpha) >> 8;
}
src_surface_pattern = (cairo_surface_pattern_t *)pattern;
src = (cairo_win32_surface_t *)src_surface_pattern->surface;
if (src->base.backend != dst->base.backend)
return CAIRO_INT_STATUS_UNSUPPORTED;
integer_transform = _cairo_matrix_is_integer_translation (&pattern->matrix, &itx, &ity);
if (!integer_transform)
return CAIRO_INT_STATUS_UNSUPPORTED;
if (alpha == 255 &&
src->format == dst->format &&
(operator == CAIRO_OPERATOR_SRC ||
(src->format == CAIRO_FORMAT_RGB24 && operator == CAIRO_OPERATOR_OVER))) {
if (!BitBlt (dst->dc,
dst_x, dst_y,
width, height,
src->dc,
src_x + itx, src_y + ity,
SRCCOPY))
return _cairo_win32_print_gdi_error ("_cairo_win32_surface_composite");
return CAIRO_STATUS_SUCCESS;
} else if (integer_transform &&
(src->format == CAIRO_FORMAT_RGB24 || src->format == CAIRO_FORMAT_ARGB32) &&
dst->format == CAIRO_FORMAT_RGB24 &&
!src->base.repeat &&
operator == CAIRO_OPERATOR_OVER) {
BLENDFUNCTION blend_function;
blend_function.BlendOp = AC_SRC_OVER;
blend_function.BlendFlags = 0;
blend_function.SourceConstantAlpha = alpha;
blend_function.AlphaFormat = src->format == CAIRO_FORMAT_ARGB32 ? AC_SRC_ALPHA : 0;
if (!AlphaBlend (dst->dc,
dst_x, dst_y,
width, height,
src->dc,
src_x + itx, src_y + ity,
width, height,
blend_function))
return _cairo_win32_print_gdi_error ("_cairo_win32_surface_composite");
return CAIRO_STATUS_SUCCESS;
}
return CAIRO_INT_STATUS_UNSUPPORTED;
}
static cairo_int_status_t
_cairo_win32_surface_fill_rectangles (void *abstract_surface,
cairo_operator_t operator,
const cairo_color_t *color,
cairo_rectangle_t *rects,
int num_rects)
{
cairo_win32_surface_t *surface = abstract_surface;
cairo_status_t status;
COLORREF new_color;
HBRUSH new_brush;
int i;
/* If we have a local image, use the fallback code; it will be as fast
* as calling out to GDI.
*/
if (surface->image)
return CAIRO_INT_STATUS_UNSUPPORTED;
/* We could support possibly support more operators for color->alpha = 0xffff.
* for CAIRO_OPERATOR_SRC, alpha doesn't matter since we know the destination
* image doesn't have alpha. (surface->pixman_image is non-NULL for all
* surfaces with alpha.)
*/
if (operator != CAIRO_OPERATOR_SRC)
return CAIRO_INT_STATUS_UNSUPPORTED;
new_color = RGB (color->red_short >> 8, color->green_short >> 8, color->blue_short >> 8);
new_brush = CreateSolidBrush (new_color);
if (!new_brush)
return _cairo_win32_print_gdi_error ("_cairo_win32_surface_fill_rectangles");
for (i = 0; i < num_rects; i++) {
RECT rect;
rect.left = rects[i].x;
rect.top = rects[i].y;
rect.right = rects[i].x + rects[i].width;
rect.bottom = rects[i].y + rects[i].height;
if (!FillRect (surface->dc, &rect, new_brush))
goto FAIL;
}
DeleteObject (new_brush);
return CAIRO_STATUS_SUCCESS;
FAIL:
status = _cairo_win32_print_gdi_error ("_cairo_win32_surface_fill_rectangles");
DeleteObject (new_brush);
return status;
}
static cairo_int_status_t
_cairo_win32_surface_set_clip_region (void *abstract_surface,
pixman_region16_t *region)
{
cairo_win32_surface_t *surface = abstract_surface;
cairo_status_t status;
/* If we are in-memory, then we set the clip on the image surface
* as well as on the underlying GDI surface.
*/
if (surface->image)
_cairo_surface_set_clip_region (surface->image, region);
/* The semantics we want is that any clip set by cairo combines
* is intersected with the clip on device context that the
* surface was created for. To implement this, we need to
* save the original clip when first setting a clip on surface.
*/
if (region == NULL) {
/* Clear any clip set by cairo, return to the original */
if (surface->set_clip) {
if (SelectClipRgn (surface->dc, surface->saved_clip) == ERROR)
return _cairo_win32_print_gdi_error ("_cairo_win32_surface_set_clip_region");
if (surface->saved_clip) {
DeleteObject (surface->saved_clip);
surface->saved_clip = NULL;
}
surface->set_clip = 0;
}
return CAIRO_STATUS_SUCCESS;
} else {
pixman_box16_t *boxes = pixman_region_rects (region);
int num_boxes = pixman_region_num_rects (region);
pixman_box16_t *extents = pixman_region_extents (region);
RGNDATA *data;
size_t data_size;
RECT *rects;
int i;
HRGN gdi_region;
/* Create a GDI region for the cairo region */
data_size = sizeof (RGNDATAHEADER) + num_boxes * sizeof (RECT);
data = malloc (data_size);
if (!data)
return CAIRO_STATUS_NO_MEMORY;
rects = (RECT *)data->Buffer;
data->rdh.dwSize = sizeof (RGNDATAHEADER);
data->rdh.iType = RDH_RECTANGLES;
data->rdh.nCount = num_boxes;
data->rdh.nRgnSize = num_boxes * sizeof (RECT);
data->rdh.rcBound.left = extents->x1;
data->rdh.rcBound.top = extents->y1;
data->rdh.rcBound.right = extents->x2;
data->rdh.rcBound.bottom = extents->y2;
for (i = 0; i < num_boxes; i++) {
rects[i].left = boxes[i].x1;
rects[i].top = boxes[i].y1;
rects[i].right = boxes[i].x2;
rects[i].bottom = boxes[i].y2;
}
gdi_region = ExtCreateRegion (NULL, data_size, data);
free (data);
if (!gdi_region)
return CAIRO_STATUS_NO_MEMORY;
if (surface->set_clip) {
/* Combine the new region with the original clip */
if (surface->saved_clip) {
if (CombineRgn (gdi_region, gdi_region, surface->saved_clip, RGN_AND) == ERROR)
goto FAIL;
}
if (SelectClipRgn (surface->dc, gdi_region) == ERROR)
goto FAIL;
} else {
/* Save the the current region */
surface->saved_clip = CreateRectRgn (0, 0, 0, 0);
if (!surface->saved_clip) {
goto FAIL; }
/* This function has no error return! */
if (GetClipRgn (surface->dc, surface->saved_clip) == 0) { /* No clip */
DeleteObject (surface->saved_clip);
surface->saved_clip = NULL;
}
if (ExtSelectClipRgn (surface->dc, gdi_region, RGN_AND) == ERROR)
goto FAIL;
surface->set_clip = 1;
}
DeleteObject (gdi_region);
return CAIRO_STATUS_SUCCESS;
FAIL:
status = _cairo_win32_print_gdi_error ("_cairo_win32_surface_set_clip_region");
DeleteObject (gdi_region);
return status;
}
}
static cairo_int_status_t
_cairo_win32_get_extents (void *abstract_surface,
cairo_rectangle_t *rectangle)
{
RECT clip_box;
if (GetClipBox (surface->dc, &clip_box) == ERROR)
return _cairo_win32_print_gdi_error ("_cairo_win3_surface_acquire_dest_image");
rectangle->x = clip_box.left;
rectangle->y = clip_box.top;
rectangle->width = clip_box.right - clip_box.left;
rectangle->height = clip_box.bottom - clip_box.top;
return CAIRO_STATUS_SUCCESS;
}
cairo_surface_t *
cairo_win32_surface_create (HDC hdc)
{
cairo_win32_surface_t *surface;
RECT rect;
/* Try to figure out the drawing bounds for the Device context
*/
if (GetClipBox (hdc, &rect) == ERROR) {
_cairo_win32_print_gdi_error ("cairo_win32_surface_create");
return NULL;
}
surface = malloc (sizeof (cairo_win32_surface_t));
if (!surface)
return NULL;
surface->image = NULL;
surface->format = CAIRO_FORMAT_RGB24;
surface->dc = hdc;
surface->bitmap = NULL;
surface->saved_dc_bitmap = NULL;
surface->clip_rect.x = rect.left;
surface->clip_rect.y = rect.top;
surface->clip_rect.width = rect.right - rect.left;
surface->clip_rect.height = rect.bottom - rect.top;
surface->set_clip = 0;
surface->saved_clip = NULL;
_cairo_surface_init (&surface->base, &cairo_win32_surface_backend);
return (cairo_surface_t *)surface;
}
/**
* _cairo_surface_is_win32:
* @surface: a #cairo_surface_t
*
* Checks if a surface is an #cairo_win32_surface_t
*
* Return value: True if the surface is an win32 surface
**/
int
_cairo_surface_is_win32 (cairo_surface_t *surface)
{
return surface->backend == &cairo_win32_surface_backend;
}
static const cairo_surface_backend_t cairo_win32_surface_backend = {
_cairo_win32_surface_create_similar,
_cairo_win32_surface_finish,
_cairo_win32_surface_acquire_source_image,
_cairo_win32_surface_release_source_image,
_cairo_win32_surface_acquire_dest_image,
_cairo_win32_surface_release_dest_image,
NULL, /* clone_similar */
_cairo_win32_surface_composite,
_cairo_win32_surface_fill_rectangles,
NULL, /* composite_trapezoids */
NULL, /* copy_page */
NULL, /* show_page */
_cairo_win32_surface_set_clip_region,
_cairo_win32_surface_get_extents,
NULL /* show_glyphs */
};
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