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/* GdkPixbuf library - Utilities and miscellaneous convenience functions
*
* Copyright (C) 1999 The Free Software Foundation
*
* Authors: Federico Mena-Quintero <federico@gimp.org>
* Cody Russell <bratsche@dfw.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <config.h>
#include "gdk-pixbuf-private.h"
/**
* gdk_pixbuf_add_alpha:
* @pixbuf: A pixbuf.
* @substitute_color: Whether to substitute a color for zero opacity. If this
* is #FALSE, then the (@r, @g, @b) arguments will be ignored.
* @r: Red value to substitute.
* @g: Green value to substitute.
* @b: Blue value to substitute.
*
* Takes an existing pixbuf and adds an alpha channel to it. If the original
* pixbuf already had alpha information, then the contents of the new pixbuf are
* exactly the same as the original's. Otherwise, the new pixbuf will have all
* pixels with full opacity if @substitute_color is #FALSE. If
* @substitute_color is #TRUE, then the color specified by (@r, @g, @b) will be
* substituted for zero opacity.
*
* Return value: A newly-created pixbuf with a reference count of 1.
**/
GdkPixbuf *
gdk_pixbuf_add_alpha (const GdkPixbuf *pixbuf,
gboolean substitute_color, guchar r, guchar g, guchar b)
{
GdkPixbuf *new_pixbuf;
int x, y;
g_return_val_if_fail (pixbuf != NULL, NULL);
g_return_val_if_fail (pixbuf->colorspace == GDK_COLORSPACE_RGB, NULL);
g_return_val_if_fail (pixbuf->n_channels == 3 || pixbuf->n_channels == 4, NULL);
g_return_val_if_fail (pixbuf->bits_per_sample == 8, NULL);
if (pixbuf->has_alpha) {
new_pixbuf = gdk_pixbuf_copy (pixbuf);
if (!new_pixbuf)
return NULL;
return new_pixbuf;
}
new_pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE, 8, pixbuf->width, pixbuf->height);
if (!new_pixbuf)
return NULL;
for (y = 0; y < pixbuf->height; y++) {
guchar *src, *dest;
guchar tr, tg, tb;
src = pixbuf->pixels + y * pixbuf->rowstride;
dest = new_pixbuf->pixels + y * new_pixbuf->rowstride;
for (x = 0; x < pixbuf->width; x++) {
tr = *dest++ = *src++;
tg = *dest++ = *src++;
tb = *dest++ = *src++;
if (substitute_color && tr == r && tg == g && tb == b)
*dest++ = 0;
else
*dest++ = 255;
}
}
return new_pixbuf;
}
/**
* gdk_pixbuf_copy_area:
* @src_pixbuf: Source pixbuf.
* @src_x: Source X coordinate within @src_pixbuf.
* @src_y: Source Y coordinate within @src_pixbuf.
* @width: Width of the area to copy.
* @height: Height of the area to copy.
* @dest_pixbuf: Destination pixbuf.
* @dest_x: X coordinate within @dest_pixbuf.
* @dest_y: Y coordinate within @dest_pixbuf.
*
* Copies a rectangular area from @src_pixbuf to @dest_pixbuf. Conversion of
* pixbuf formats is done automatically.
**/
void
gdk_pixbuf_copy_area (const GdkPixbuf *src_pixbuf,
int src_x, int src_y,
int width, int height,
GdkPixbuf *dest_pixbuf,
int dest_x, int dest_y)
{
g_return_if_fail (src_pixbuf != NULL);
g_return_if_fail (dest_pixbuf != NULL);
g_return_if_fail (src_x >= 0 && src_x + width <= src_pixbuf->width);
g_return_if_fail (src_y >= 0 && src_y + height <= src_pixbuf->height);
g_return_if_fail (dest_x >= 0 && dest_x + width <= dest_pixbuf->width);
g_return_if_fail (dest_y >= 0 && dest_y + height <= dest_pixbuf->height);
/* This will perform format conversions automatically */
gdk_pixbuf_scale (src_pixbuf,
dest_pixbuf,
dest_x, dest_y,
width, height,
(double) (dest_x - src_x),
(double) (dest_y - src_y),
1.0, 1.0,
GDK_INTERP_NEAREST);
}
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