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netsurf/frontends/gtk/gdk.c

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3.7 KiB

/*
* Copyright 2011 Vincent Sanders <vince@netsurf-browser.org>
*
* This file is part of NetSurf, http://www.netsurf-browser.org/
*
* NetSurf is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* NetSurf is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <string.h>
#include "utils/log.h"
#include "gtk/gdk.h"
static void
convert_alpha(guchar *dest_data,
int dest_stride,
guchar *src_data,
int src_stride,
int width,
int height)
{
int x, y;
for (y = 0; y < height; y++) {
/* this cast is safe, the buffer is appropriately aligned */
guint32 *src = (void *) src_data;
for (x = 0; x < width; x++) {
guint alpha = src[x] >> 24;
if (alpha == 0) {
dest_data[x * 4 + 0] = 0;
dest_data[x * 4 + 1] = 0;
dest_data[x * 4 + 2] = 0;
} else {
dest_data[x * 4 + 0] = (((src[x] & 0xff0000) >> 16) * 255 + alpha / 2) / alpha;
dest_data[x * 4 + 1] = (((src[x] & 0x00ff00) >> 8) * 255 + alpha / 2) / alpha;
dest_data[x * 4 + 2] = (((src[x] & 0x0000ff) >> 0) * 255 + alpha / 2) / alpha;
}
dest_data[x * 4 + 3] = alpha;
}
src_data += src_stride;
dest_data += dest_stride;
}
}
GdkPixbuf *
nsgdk_pixbuf_get_from_surface(cairo_surface_t *surface, int scwidth, int scheight)
{
int width, height; /* source width and height */
cairo_surface_t *scsurface; /* scaled surface */
cairo_t *cr; /* cairo context for scaled surface */
GdkPixbuf *pixbuf; /* The result pixel buffer */
/* create pixmap */
pixbuf = gdk_pixbuf_new(GDK_COLORSPACE_RGB, true, 8, scwidth, scheight);
if (pixbuf == NULL) {
return NULL;
}
memset(gdk_pixbuf_get_pixels(pixbuf),
0xff,
gdk_pixbuf_get_rowstride(pixbuf) * (size_t)scheight);
/* scale cairo surface into new surface the target size */
cairo_surface_flush(surface); /* ensure source surface is ready */
/* get source surface dimensions */
width = cairo_image_surface_get_width(surface);
height = cairo_image_surface_get_height(surface);
/* scaled surface always has an alpha chanel for ease */
scsurface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, scwidth, scheight);
if (cairo_surface_status(scsurface) != CAIRO_STATUS_SUCCESS) {
cairo_surface_destroy(scsurface);
g_object_unref(pixbuf);
NSLOG(netsurf, INFO, "Surface creation failed");
return NULL;
}
cr = cairo_create(scsurface);
/* Scale *before* setting the source surface */
cairo_scale(cr, (double)scwidth / width, (double)scheight / height);
cairo_set_source_surface(cr, surface, 0, 0);
/* To avoid getting the edge pixels blended with 0
* alpha, which would occur with the default
* EXTEND_NONE. Use EXTEND_PAD for 1.2 or newer
*/
cairo_pattern_set_extend(cairo_get_source(cr), CAIRO_EXTEND_REFLECT);
/* Replace the destination with the source instead of overlaying */
cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
/* Do the actual drawing */
cairo_paint(cr);
cairo_destroy(cr);
/* copy data from surface into pixmap */
convert_alpha(gdk_pixbuf_get_pixels(pixbuf),
gdk_pixbuf_get_rowstride(pixbuf),
cairo_image_surface_get_data(scsurface),
cairo_image_surface_get_stride(scsurface),
scwidth, scheight);
cairo_surface_destroy(scsurface);
return pixbuf;
}