forked from AuroraMiddleware/gtk
7e8d8218b9
We're not in the business of adding Cairo APIs. That's Cairo's job.
Also, we don't need this API anywhere like the original commit claimed,
so there's no need to make it available in any way.
This reverts commit afa6cc2369.
459 lines
13 KiB
C
459 lines
13 KiB
C
/* GDK - The GIMP Drawing Kit
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* Copyright (C) 2005 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "config.h"
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#include "gdkcairo.h"
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#include "gdkinternals.h"
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#include <math.h>
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/**
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* SECTION:cairo_interaction
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* @Short_description: Functions to support using cairo
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* @Title: Cairo Interaction
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*
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* [Cairo](http://cairographics.org) is a graphics
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* library that supports vector graphics and image compositing that
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* can be used with GDK and GTK.
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*
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* GDK does not wrap the cairo API, instead it allows to create cairo
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* contexts which can be used to draw on #GdkSurfaces. Additional
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* functions allow use #GdkRectangles with cairo and to use #GdkRGBAs,
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* #GdkPixbufs and #GdkSurfaces as sources for drawing operations.
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*/
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/**
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* gdk_cairo_get_clip_rectangle:
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* @cr: a cairo context
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* @rect: (out) (allow-none): return location for the clip, or %NULL
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*
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* This is a convenience function around cairo_clip_extents().
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* It rounds the clip extents to integer coordinates and returns
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* a boolean indicating if a clip area exists.
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*
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* Returns: %TRUE if a clip rectangle exists, %FALSE if all of @cr is
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* clipped and all drawing can be skipped
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*/
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gboolean
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gdk_cairo_get_clip_rectangle (cairo_t *cr,
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GdkRectangle *rect)
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{
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double x1, y1, x2, y2;
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gboolean clip_exists;
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cairo_clip_extents (cr, &x1, &y1, &x2, &y2);
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clip_exists = x1 < x2 && y1 < y2;
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if (rect)
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{
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x1 = floor (x1);
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y1 = floor (y1);
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x2 = ceil (x2);
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y2 = ceil (y2);
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rect->x = CLAMP (x1, G_MININT, G_MAXINT);
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rect->y = CLAMP (y1, G_MININT, G_MAXINT);
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rect->width = CLAMP (x2 - x1, G_MININT, G_MAXINT);
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rect->height = CLAMP (y2 - y1, G_MININT, G_MAXINT);
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}
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return clip_exists;
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}
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/**
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* gdk_cairo_set_source_rgba:
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* @cr: a cairo context
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* @rgba: a #GdkRGBA
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*
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* Sets the specified #GdkRGBA as the source color of @cr.
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*/
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void
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gdk_cairo_set_source_rgba (cairo_t *cr,
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const GdkRGBA *rgba)
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{
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g_return_if_fail (cr != NULL);
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g_return_if_fail (rgba != NULL);
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cairo_set_source_rgba (cr,
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rgba->red,
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rgba->green,
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rgba->blue,
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rgba->alpha);
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}
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/**
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* gdk_cairo_rectangle:
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* @cr: a cairo context
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* @rectangle: a #GdkRectangle
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*
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* Adds the given rectangle to the current path of @cr.
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*/
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void
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gdk_cairo_rectangle (cairo_t *cr,
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const GdkRectangle *rectangle)
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{
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g_return_if_fail (cr != NULL);
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g_return_if_fail (rectangle != NULL);
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cairo_rectangle (cr,
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rectangle->x, rectangle->y,
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rectangle->width, rectangle->height);
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}
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/**
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* gdk_cairo_region:
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* @cr: a cairo context
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* @region: a #cairo_region_t
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*
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* Adds the given region to the current path of @cr.
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*/
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void
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gdk_cairo_region (cairo_t *cr,
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const cairo_region_t *region)
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{
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cairo_rectangle_int_t box;
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gint n_boxes, i;
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g_return_if_fail (cr != NULL);
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g_return_if_fail (region != NULL);
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n_boxes = cairo_region_num_rectangles (region);
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for (i = 0; i < n_boxes; i++)
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{
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cairo_region_get_rectangle (region, i, &box);
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cairo_rectangle (cr, box.x, box.y, box.width, box.height);
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}
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}
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void
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gdk_cairo_surface_paint_pixbuf (cairo_surface_t *surface,
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const GdkPixbuf *pixbuf)
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{
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gint width, height;
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guchar *gdk_pixels, *cairo_pixels;
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int gdk_rowstride, cairo_stride;
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int n_channels;
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int j;
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if (cairo_surface_status (surface) != CAIRO_STATUS_SUCCESS)
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return;
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/* This function can't just copy any pixbuf to any surface, be
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* sure to read the invariants here before calling it */
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g_assert (cairo_surface_get_type (surface) == CAIRO_SURFACE_TYPE_IMAGE);
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g_assert (cairo_image_surface_get_format (surface) == CAIRO_FORMAT_RGB24 ||
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cairo_image_surface_get_format (surface) == CAIRO_FORMAT_ARGB32);
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g_assert (cairo_image_surface_get_width (surface) == gdk_pixbuf_get_width (pixbuf));
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g_assert (cairo_image_surface_get_height (surface) == gdk_pixbuf_get_height (pixbuf));
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cairo_surface_flush (surface);
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width = gdk_pixbuf_get_width (pixbuf);
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height = gdk_pixbuf_get_height (pixbuf);
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gdk_pixels = gdk_pixbuf_get_pixels (pixbuf);
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gdk_rowstride = gdk_pixbuf_get_rowstride (pixbuf);
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n_channels = gdk_pixbuf_get_n_channels (pixbuf);
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cairo_stride = cairo_image_surface_get_stride (surface);
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cairo_pixels = cairo_image_surface_get_data (surface);
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for (j = height; j; j--)
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{
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guchar *p = gdk_pixels;
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guchar *q = cairo_pixels;
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if (n_channels == 3)
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{
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guchar *end = p + 3 * width;
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while (p < end)
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{
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#if G_BYTE_ORDER == G_LITTLE_ENDIAN
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q[0] = p[2];
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q[1] = p[1];
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q[2] = p[0];
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q[3] = 0xFF;
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#else
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q[0] = 0xFF;
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q[1] = p[0];
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q[2] = p[1];
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q[3] = p[2];
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#endif
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p += 3;
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q += 4;
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}
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}
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else
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{
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guchar *end = p + 4 * width;
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guint t1,t2,t3;
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#define MULT(d,c,a,t) G_STMT_START { t = c * a + 0x80; d = ((t >> 8) + t) >> 8; } G_STMT_END
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while (p < end)
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{
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#if G_BYTE_ORDER == G_LITTLE_ENDIAN
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MULT(q[0], p[2], p[3], t1);
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MULT(q[1], p[1], p[3], t2);
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MULT(q[2], p[0], p[3], t3);
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q[3] = p[3];
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#else
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q[0] = p[3];
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MULT(q[1], p[0], p[3], t1);
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MULT(q[2], p[1], p[3], t2);
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MULT(q[3], p[2], p[3], t3);
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#endif
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p += 4;
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q += 4;
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}
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#undef MULT
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}
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gdk_pixels += gdk_rowstride;
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cairo_pixels += cairo_stride;
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}
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cairo_surface_mark_dirty (surface);
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}
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/**
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* gdk_cairo_set_source_pixbuf:
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* @cr: a cairo context
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* @pixbuf: a #GdkPixbuf
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* @pixbuf_x: X coordinate of location to place upper left corner of @pixbuf
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* @pixbuf_y: Y coordinate of location to place upper left corner of @pixbuf
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*
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* Sets the given pixbuf as the source pattern for @cr.
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*
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* The pattern has an extend mode of %CAIRO_EXTEND_NONE and is aligned
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* so that the origin of @pixbuf is @pixbuf_x, @pixbuf_y.
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*/
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void
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gdk_cairo_set_source_pixbuf (cairo_t *cr,
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const GdkPixbuf *pixbuf,
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gdouble pixbuf_x,
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gdouble pixbuf_y)
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{
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cairo_format_t format;
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cairo_surface_t *surface;
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if (gdk_pixbuf_get_n_channels (pixbuf) == 3)
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format = CAIRO_FORMAT_RGB24;
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else
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format = CAIRO_FORMAT_ARGB32;
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surface = cairo_surface_create_similar_image (cairo_get_target (cr),
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format,
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gdk_pixbuf_get_width (pixbuf),
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gdk_pixbuf_get_height (pixbuf));
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gdk_cairo_surface_paint_pixbuf (surface, pixbuf);
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cairo_set_source_surface (cr, surface, pixbuf_x, pixbuf_y);
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cairo_surface_destroy (surface);
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}
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/*
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* _gdk_cairo_surface_extents:
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* @surface: surface to measure
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* @extents: (out): rectangle to put the extents
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*
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* Measures the area covered by @surface and puts it into @extents.
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*
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* Note that this function respects device offsets set on @surface.
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* If @surface is unbounded, the resulting extents will be empty and
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* not be a maximal sized rectangle. This is to avoid careless coding.
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* You must explicitly check the return value of you want to handle
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* that case.
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*
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* Returns: %TRUE if the extents fit in a #GdkRectangle, %FALSE if not
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*/
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gboolean
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_gdk_cairo_surface_extents (cairo_surface_t *surface,
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GdkRectangle *extents)
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{
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double x1, x2, y1, y2;
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cairo_t *cr;
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g_return_val_if_fail (surface != NULL, FALSE);
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g_return_val_if_fail (extents != NULL, FALSE);
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cr = cairo_create (surface);
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cairo_clip_extents (cr, &x1, &y1, &x2, &y2);
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cairo_destroy (cr);
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x1 = floor (x1);
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y1 = floor (y1);
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x2 = ceil (x2);
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y2 = ceil (y2);
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x2 -= x1;
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y2 -= y1;
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if (x1 < G_MININT || x1 > G_MAXINT ||
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y1 < G_MININT || y1 > G_MAXINT ||
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x2 > G_MAXINT || y2 > G_MAXINT)
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{
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extents->x = extents->y = extents->width = extents->height = 0;
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return FALSE;
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}
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extents->x = x1;
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extents->y = y1;
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extents->width = x2;
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extents->height = y2;
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return TRUE;
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}
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/* This function originally from Jean-Edouard Lachand-Robert, and
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* available at www.codeguru.com. Simplified for our needs, not sure
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* how much of the original code left any longer. Now handles just
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* one-bit deep bitmaps (in Window parlance, ie those that GDK calls
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* bitmaps (and not pixmaps), with zero pixels being transparent.
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*/
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/**
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* gdk_cairo_region_create_from_surface:
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* @surface: a cairo surface
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*
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* Creates region that describes covers the area where the given
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* @surface is more than 50% opaque.
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*
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* This function takes into account device offsets that might be
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* set with cairo_surface_set_device_offset().
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*
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* Returns: A #cairo_region_t; must be freed with cairo_region_destroy()
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*/
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cairo_region_t *
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gdk_cairo_region_create_from_surface (cairo_surface_t *surface)
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{
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cairo_region_t *region;
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GdkRectangle extents, rect;
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cairo_surface_t *image;
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cairo_t *cr;
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gint x, y, stride;
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guchar *data;
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_gdk_cairo_surface_extents (surface, &extents);
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if (cairo_surface_get_content (surface) == CAIRO_CONTENT_COLOR)
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return cairo_region_create_rectangle (&extents);
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if (cairo_surface_get_type (surface) != CAIRO_SURFACE_TYPE_IMAGE ||
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cairo_image_surface_get_format (surface) != CAIRO_FORMAT_A1)
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{
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/* coerce to an A1 image */
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image = cairo_image_surface_create (CAIRO_FORMAT_A1,
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extents.width, extents.height);
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cr = cairo_create (image);
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cairo_set_source_surface (cr, surface, -extents.x, -extents.y);
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cairo_paint (cr);
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cairo_destroy (cr);
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}
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else
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image = cairo_surface_reference (surface);
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/* Flush the surface to make sure that the rendering is up to date. */
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cairo_surface_flush (image);
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data = cairo_image_surface_get_data (image);
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stride = cairo_image_surface_get_stride (image);
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region = cairo_region_create ();
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for (y = 0; y < extents.height; y++)
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{
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for (x = 0; x < extents.width; x++)
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{
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/* Search for a continuous range of "non transparent pixels"*/
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gint x0 = x;
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while (x < extents.width)
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{
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#if G_BYTE_ORDER == G_LITTLE_ENDIAN
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if (((data[x / 8] >> (x%8)) & 1) == 0)
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#else
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if (((data[x / 8] >> (7-(x%8))) & 1) == 0)
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#endif
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/* This pixel is "transparent"*/
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break;
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x++;
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}
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if (x > x0)
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{
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/* Add the pixels (x0, y) to (x, y+1) as a new rectangle
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* in the region
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*/
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rect.x = x0;
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rect.width = x - x0;
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rect.y = y;
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rect.height = 1;
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cairo_region_union_rectangle (region, &rect);
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}
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}
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data += stride;
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}
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cairo_surface_destroy (image);
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cairo_region_translate (region, extents.x, extents.y);
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return region;
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}
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cairo_region_t *
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gdk_cairo_region_from_clip (cairo_t *cr)
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{
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cairo_rectangle_list_t *rectangles;
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cairo_region_t *region;
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int i;
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rectangles = cairo_copy_clip_rectangle_list (cr);
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if (rectangles->status != CAIRO_STATUS_SUCCESS)
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return NULL;
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region = cairo_region_create ();
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for (i = 0; i < rectangles->num_rectangles; i++)
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{
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cairo_rectangle_int_t clip_rect;
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cairo_rectangle_t *rect;
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rect = &rectangles->rectangles[i];
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/* Here we assume clip rects are ints for direct targets, which
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is true for cairo */
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clip_rect.x = (int)rect->x;
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clip_rect.y = (int)rect->y;
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clip_rect.width = (int)rect->width;
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clip_rect.height = (int)rect->height;
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cairo_region_union_rectangle (region, &clip_rect);
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}
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cairo_rectangle_list_destroy (rectangles);
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return region;
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}
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