mirror of
https://gitlab.gnome.org/GNOME/gtk.git
synced 2024-10-04 04:57:37 +00:00
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
|
||
*
|
||
* Copyright (C) 1999 The Free Software Foundation
|
||
*
|
||
* Authors: Federico Mena-Quintero <federico@gimp.org>
|
||
* Cody Russell <bratsche@gnome.org>
|
||
*
|
||
* This library is free software; you can redistribute it and/or
|
||
* modify it under the terms of the GNU Lesser 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
|
||
* Lesser General Public License for more details.
|
||
*
|
||
* You should have received a copy of the GNU Lesser 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"
|
||
#include <string.h>
|
||
|
||
|
||
|
||
/**
|
||
* gdk_pixbuf_add_alpha:
|
||
* @pixbuf: A #GdkPixbuf.
|
||
* @substitute_color: Whether to set a color to 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 existing pixbuf already had an alpha channel, the channel
|
||
* values are copied from the original; otherwise, the alpha channel
|
||
* is initialized to 255 (full opacity).
|
||
*
|
||
* If @substitute_color is %TRUE, then the color specified by (@r, @g, @b) will be
|
||
* assigned zero opacity. That is, if you pass (255, 255, 255) for the
|
||
* substitute color, all white pixels will become fully transparent.
|
||
*
|
||
* 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;
|
||
|
||
if (!substitute_color)
|
||
return new_pixbuf;
|
||
} else {
|
||
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;
|
||
|
||
if (pixbuf->has_alpha) {
|
||
/* Just subst color, we already copied everything else */
|
||
for (x = 0; x < pixbuf->width; x++) {
|
||
if (src[0] == r && src[1] == g && src[2] == b)
|
||
dest[3] = 0;
|
||
src += 4;
|
||
dest += 4;
|
||
}
|
||
} else {
|
||
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);
|
||
|
||
g_return_if_fail (!(gdk_pixbuf_get_has_alpha (src_pixbuf) && !gdk_pixbuf_get_has_alpha (dest_pixbuf)));
|
||
|
||
/* 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);
|
||
}
|
||
|
||
|
||
|
||
/**
|
||
* gdk_pixbuf_saturate_and_pixelate:
|
||
* @src: source image
|
||
* @dest: place to write modified version of @src
|
||
* @saturation: saturation factor
|
||
* @pixelate: whether to pixelate
|
||
*
|
||
* Modifies saturation and optionally pixelates @src, placing the
|
||
* result in @dest. @src and @dest may be the same pixbuf with no ill
|
||
* effects. If @saturation is 1.0 then saturation is not changed. If
|
||
* it's less than 1.0, saturation is reduced (the image is darkened);
|
||
* if greater than 1.0, saturation is increased (the image is
|
||
* brightened). If @pixelate is %TRUE, then pixels are faded in a
|
||
* checkerboard pattern to create a pixelated image. @src and @dest
|
||
* must have the same image format, size, and rowstride.
|
||
*
|
||
**/
|
||
void
|
||
gdk_pixbuf_saturate_and_pixelate(const GdkPixbuf *src,
|
||
GdkPixbuf *dest,
|
||
gfloat saturation,
|
||
gboolean pixelate)
|
||
{
|
||
/* NOTE that src and dest MAY be the same pixbuf! */
|
||
|
||
g_return_if_fail (GDK_IS_PIXBUF (src));
|
||
g_return_if_fail (GDK_IS_PIXBUF (dest));
|
||
g_return_if_fail (gdk_pixbuf_get_height (src) == gdk_pixbuf_get_height (dest));
|
||
g_return_if_fail (gdk_pixbuf_get_width (src) == gdk_pixbuf_get_width (dest));
|
||
g_return_if_fail (gdk_pixbuf_get_has_alpha (src) == gdk_pixbuf_get_has_alpha (dest));
|
||
g_return_if_fail (gdk_pixbuf_get_colorspace (src) == gdk_pixbuf_get_colorspace (dest));
|
||
|
||
if (saturation == 1.0 && !pixelate) {
|
||
if (dest != src)
|
||
memcpy (gdk_pixbuf_get_pixels (dest),
|
||
gdk_pixbuf_get_pixels (src),
|
||
gdk_pixbuf_get_height (src) * gdk_pixbuf_get_rowstride (src));
|
||
} else {
|
||
int i, j, t;
|
||
int width, height, has_alpha, src_rowstride, dest_rowstride, bytes_per_pixel;
|
||
guchar *src_line;
|
||
guchar *dest_line;
|
||
guchar *src_pixel;
|
||
guchar *dest_pixel;
|
||
guchar intensity;
|
||
|
||
has_alpha = gdk_pixbuf_get_has_alpha (src);
|
||
bytes_per_pixel = has_alpha ? 4 : 3;
|
||
width = gdk_pixbuf_get_width (src);
|
||
height = gdk_pixbuf_get_height (src);
|
||
src_rowstride = gdk_pixbuf_get_rowstride (src);
|
||
dest_rowstride = gdk_pixbuf_get_rowstride (dest);
|
||
|
||
src_line = gdk_pixbuf_get_pixels (src);
|
||
dest_line = gdk_pixbuf_get_pixels (dest);
|
||
|
||
#define DARK_FACTOR 0.7
|
||
#define INTENSITY(r, g, b) ((r) * 0.30 + (g) * 0.59 + (b) * 0.11)
|
||
#define CLAMP_UCHAR(v) (t = (v), CLAMP (t, 0, 255))
|
||
#define SATURATE(v) ((1.0 - saturation) * intensity + saturation * (v))
|
||
|
||
for (i = 0 ; i < height ; i++) {
|
||
src_pixel = src_line;
|
||
src_line += src_rowstride;
|
||
dest_pixel = dest_line;
|
||
dest_line += dest_rowstride;
|
||
|
||
for (j = 0 ; j < width ; j++) {
|
||
intensity = INTENSITY (src_pixel[0], src_pixel[1], src_pixel[2]);
|
||
if (pixelate && (i + j) % 2 == 0) {
|
||
dest_pixel[0] = intensity / 2 + 127;
|
||
dest_pixel[1] = intensity / 2 + 127;
|
||
dest_pixel[2] = intensity / 2 + 127;
|
||
} else if (pixelate) {
|
||
dest_pixel[0] = CLAMP_UCHAR ((SATURATE (src_pixel[0])) * DARK_FACTOR);
|
||
dest_pixel[1] = CLAMP_UCHAR ((SATURATE (src_pixel[1])) * DARK_FACTOR);
|
||
dest_pixel[2] = CLAMP_UCHAR ((SATURATE (src_pixel[2])) * DARK_FACTOR);
|
||
} else {
|
||
dest_pixel[0] = CLAMP_UCHAR (SATURATE (src_pixel[0]));
|
||
dest_pixel[1] = CLAMP_UCHAR (SATURATE (src_pixel[1]));
|
||
dest_pixel[2] = CLAMP_UCHAR (SATURATE (src_pixel[2]));
|
||
}
|
||
|
||
if (has_alpha)
|
||
dest_pixel[3] = src_pixel[3];
|
||
|
||
src_pixel += bytes_per_pixel;
|
||
dest_pixel += bytes_per_pixel;
|
||
}
|
||
}
|
||
}
|
||
}
|