b24d44e421
Tue Jan 8 10:58:04 2002 Owen Taylor <otaylor@redhat.com> * gdk-pixbuf-util.c (gdk_pixbuf_saturate_and_pixelate): - Massive cleanup, make actually legible. - Fix some clamp-to-range bugs found by Jim Cape (#68231). - Add a g_return_if_fail() if src and dest alpha don't match. - Allow for src_rowstride != dest_rowstride.
246 lines
9.3 KiB
C
246 lines
9.3 KiB
C
/* GdkPixbuf library - Utilities and miscellaneous convenience functions
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*
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* Copyright (C) 1999 The Free Software Foundation
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*
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* Authors: Federico Mena-Quintero <federico@gimp.org>
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* Cody Russell <bratsche@gnome.org>
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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, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include <config.h>
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#include "gdk-pixbuf-private.h"
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#include <string.h>
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/**
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* gdk_pixbuf_add_alpha:
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* @pixbuf: A #GdkPixbuf.
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* @substitute_color: Whether to set a color to zero opacity. If this
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* is %FALSE, then the (@r, @g, @b) arguments will be ignored.
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* @r: Red value to substitute.
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* @g: Green value to substitute.
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* @b: Blue value to substitute.
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*
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* Takes an existing pixbuf and adds an alpha channel to it.
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* If the existing pixbuf already had an alpha channel, the channel
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* values are copied from the original; otherwise, the alpha channel
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* is initialized to 255 (full opacity).
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*
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* If @substitute_color is %TRUE, then the color specified by (@r, @g, @b) will be
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* assigned zero opacity. That is, if you pass (255, 255, 255) for the
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* substitute color, all white pixels will become fully transparent.
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*
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* Return value: A newly-created pixbuf with a reference count of 1.
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**/
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GdkPixbuf *
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gdk_pixbuf_add_alpha (const GdkPixbuf *pixbuf,
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gboolean substitute_color, guchar r, guchar g, guchar b)
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{
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GdkPixbuf *new_pixbuf;
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int x, y;
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g_return_val_if_fail (pixbuf != NULL, NULL);
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g_return_val_if_fail (pixbuf->colorspace == GDK_COLORSPACE_RGB, NULL);
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g_return_val_if_fail (pixbuf->n_channels == 3 || pixbuf->n_channels == 4, NULL);
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g_return_val_if_fail (pixbuf->bits_per_sample == 8, NULL);
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if (pixbuf->has_alpha) {
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new_pixbuf = gdk_pixbuf_copy (pixbuf);
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if (!new_pixbuf)
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return NULL;
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if (!substitute_color)
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return new_pixbuf;
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} else {
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new_pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE, 8, pixbuf->width, pixbuf->height);
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}
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if (!new_pixbuf)
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return NULL;
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for (y = 0; y < pixbuf->height; y++) {
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guchar *src, *dest;
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guchar tr, tg, tb;
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src = pixbuf->pixels + y * pixbuf->rowstride;
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dest = new_pixbuf->pixels + y * new_pixbuf->rowstride;
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if (pixbuf->has_alpha) {
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/* Just subst color, we already copied everything else */
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for (x = 0; x < pixbuf->width; x++) {
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if (src[0] == r && src[1] == g && src[2] == b)
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dest[3] = 0;
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src += 4;
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dest += 4;
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}
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} else {
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for (x = 0; x < pixbuf->width; x++) {
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tr = *dest++ = *src++;
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tg = *dest++ = *src++;
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tb = *dest++ = *src++;
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if (substitute_color && tr == r && tg == g && tb == b)
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*dest++ = 0;
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else
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*dest++ = 255;
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}
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}
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}
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return new_pixbuf;
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}
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/**
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* gdk_pixbuf_copy_area:
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* @src_pixbuf: Source pixbuf.
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* @src_x: Source X coordinate within @src_pixbuf.
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* @src_y: Source Y coordinate within @src_pixbuf.
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* @width: Width of the area to copy.
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* @height: Height of the area to copy.
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* @dest_pixbuf: Destination pixbuf.
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* @dest_x: X coordinate within @dest_pixbuf.
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* @dest_y: Y coordinate within @dest_pixbuf.
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*
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* Copies a rectangular area from @src_pixbuf to @dest_pixbuf. Conversion of
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* pixbuf formats is done automatically.
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**/
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void
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gdk_pixbuf_copy_area (const GdkPixbuf *src_pixbuf,
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int src_x, int src_y,
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int width, int height,
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GdkPixbuf *dest_pixbuf,
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int dest_x, int dest_y)
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{
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g_return_if_fail (src_pixbuf != NULL);
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g_return_if_fail (dest_pixbuf != NULL);
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g_return_if_fail (src_x >= 0 && src_x + width <= src_pixbuf->width);
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g_return_if_fail (src_y >= 0 && src_y + height <= src_pixbuf->height);
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g_return_if_fail (dest_x >= 0 && dest_x + width <= dest_pixbuf->width);
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g_return_if_fail (dest_y >= 0 && dest_y + height <= dest_pixbuf->height);
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g_return_if_fail (!(gdk_pixbuf_get_has_alpha (src_pixbuf) && !gdk_pixbuf_get_has_alpha (dest_pixbuf)));
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/* This will perform format conversions automatically */
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gdk_pixbuf_scale (src_pixbuf,
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dest_pixbuf,
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dest_x, dest_y,
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width, height,
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(double) (dest_x - src_x),
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(double) (dest_y - src_y),
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1.0, 1.0,
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GDK_INTERP_NEAREST);
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}
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/**
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* gdk_pixbuf_saturate_and_pixelate:
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* @src: source image
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* @dest: place to write modified version of @src
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* @saturation: saturation factor
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* @pixelate: whether to pixelate
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*
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* Modifies saturation and optionally pixelates @src, placing the
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* result in @dest. @src and @dest may be the same pixbuf with no ill
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* effects. If @saturation is 1.0 then saturation is not changed. If
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* it's less than 1.0, saturation is reduced (the image is darkened);
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* if greater than 1.0, saturation is increased (the image is
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* brightened). If @pixelate is %TRUE, then pixels are faded in a
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* checkerboard pattern to create a pixelated image. @src and @dest
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* must have the same image format, size, and rowstride.
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*
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**/
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void
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gdk_pixbuf_saturate_and_pixelate(const GdkPixbuf *src,
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GdkPixbuf *dest,
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gfloat saturation,
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gboolean pixelate)
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{
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/* NOTE that src and dest MAY be the same pixbuf! */
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g_return_if_fail (GDK_IS_PIXBUF (src));
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g_return_if_fail (GDK_IS_PIXBUF (dest));
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g_return_if_fail (gdk_pixbuf_get_height (src) == gdk_pixbuf_get_height (dest));
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g_return_if_fail (gdk_pixbuf_get_width (src) == gdk_pixbuf_get_width (dest));
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g_return_if_fail (gdk_pixbuf_get_has_alpha (src) == gdk_pixbuf_get_has_alpha (dest));
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g_return_if_fail (gdk_pixbuf_get_colorspace (src) == gdk_pixbuf_get_colorspace (dest));
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if (saturation == 1.0 && !pixelate) {
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if (dest != src)
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memcpy (gdk_pixbuf_get_pixels (dest),
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gdk_pixbuf_get_pixels (src),
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gdk_pixbuf_get_height (src) * gdk_pixbuf_get_rowstride (src));
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} else {
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int i, j, t;
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int width, height, has_alpha, src_rowstride, dest_rowstride, bytes_per_pixel;
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guchar *src_line;
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guchar *dest_line;
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guchar *src_pixel;
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guchar *dest_pixel;
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guchar intensity;
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has_alpha = gdk_pixbuf_get_has_alpha (src);
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bytes_per_pixel = has_alpha ? 4 : 3;
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width = gdk_pixbuf_get_width (src);
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height = gdk_pixbuf_get_height (src);
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src_rowstride = gdk_pixbuf_get_rowstride (src);
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dest_rowstride = gdk_pixbuf_get_rowstride (dest);
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src_line = gdk_pixbuf_get_pixels (src);
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dest_line = gdk_pixbuf_get_pixels (dest);
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#define DARK_FACTOR 0.7
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#define INTENSITY(r, g, b) ((r) * 0.30 + (g) * 0.59 + (b) * 0.11)
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#define CLAMP_UCHAR(v) (t = (v), CLAMP (t, 0, 255))
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#define SATURATE(v) ((1.0 - saturation) * intensity + saturation * (v))
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for (i = 0 ; i < height ; i++) {
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src_pixel = src_line;
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src_line += src_rowstride;
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dest_pixel = dest_line;
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dest_line += dest_rowstride;
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for (j = 0 ; j < width ; j++) {
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intensity = INTENSITY (src_pixel[0], src_pixel[1], src_pixel[2]);
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if (pixelate && (i + j) % 2 == 0) {
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dest_pixel[0] = intensity / 2 + 127;
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dest_pixel[1] = intensity / 2 + 127;
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dest_pixel[2] = intensity / 2 + 127;
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} else if (pixelate) {
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dest_pixel[0] = CLAMP_UCHAR ((SATURATE (src_pixel[0])) * DARK_FACTOR);
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dest_pixel[1] = CLAMP_UCHAR ((SATURATE (src_pixel[1])) * DARK_FACTOR);
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dest_pixel[2] = CLAMP_UCHAR ((SATURATE (src_pixel[2])) * DARK_FACTOR);
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} else {
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dest_pixel[0] = CLAMP_UCHAR (SATURATE (src_pixel[0]));
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dest_pixel[1] = CLAMP_UCHAR (SATURATE (src_pixel[1]));
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dest_pixel[2] = CLAMP_UCHAR (SATURATE (src_pixel[2]));
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}
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if (has_alpha)
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dest_pixel[3] = src_pixel[3];
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src_pixel += bytes_per_pixel;
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dest_pixel += bytes_per_pixel;
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}
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}
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}
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}
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