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/* GdkPixbuf library - Rendering functions
*
* Copyright (C) 1999 The Free Software Foundation
*
* Author: Federico Mena-Quintero <federico@gimp.org>
*
* 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/gdk.h>
#include <libart_lgpl/art_rect.h>
#include "gdk-pixbuf.h"
/**
* gdk_pixbuf_render_threshold_alpha:
* @pixbuf: A pixbuf.
* @bitmap: Bitmap where the bilevel mask will be painted to.
* @src_x: Source X coordinate.
* @src_y: source Y coordinate.
* @dest_x: Destination X coordinate.
* @dest_y: Destination Y coordinate.
* @width: Width of region to threshold.
* @height: Height of region to threshold.
* @alpha_threshold: Opacity values below this will be painted as zero; all
* other values will be painted as one.
*
* Takes the opacity values in a pixbuf and thresholds them to produce a
* bi-level alpha mask that can be used as a clipping mask for a drawable.
**/
void
gdk_pixbuf_render_threshold_alpha (GdkPixbuf *pixbuf, GdkBitmap *bitmap,
int src_x, int src_y,
int dest_x, int dest_y,
int width, int height,
int alpha_threshold)
{
ArtPixBuf *apb;
GdkGC *gc;
GdkColor color;
int x, y;
guchar *p;
int start, start_status;
int status;
g_return_if_fail (pixbuf != NULL);
apb = pixbuf->art_pixbuf;
g_return_if_fail (apb->format == ART_PIX_RGB);
g_return_if_fail (apb->n_channels == 3 || apb->n_channels == 4);
g_return_if_fail (apb->bits_per_sample == 8);
g_return_if_fail (bitmap != NULL);
g_return_if_fail (src_x >= 0 && src_x + width <= apb->width);
g_return_if_fail (src_y >= 0 && src_y + height <= apb->height);
g_return_if_fail (alpha_threshold >= 0 && alpha_threshold <= 255);
gc = gdk_gc_new (bitmap);
if (!apb->has_alpha) {
color.pixel = (alpha_threshold == 255) ? 0 : 1;
gdk_gc_set_foreground (gc, &color);
gdk_draw_rectangle (bitmap, gc, TRUE, dest_x, dest_y, width, height);
gdk_gc_unref (gc);
return;
}
color.pixel = 0;
gdk_gc_set_foreground (gc, &color);
gdk_draw_rectangle (bitmap, gc, TRUE, dest_x, dest_y, width, height);
for (y = 0; y < height; y++) {
p = (apb->pixels + (y + src_y) * apb->rowstride + src_x * apb->n_channels
+ apb->n_channels - 1);
start = 0;
start_status = *p < alpha_threshold;
for (x = 0; x < width; x++) {
status = *p < alpha_threshold;
if (status != start_status) {
color.pixel = start_status ? 0 : 1;
gdk_gc_set_foreground (gc, &color);
gdk_draw_line (bitmap, gc,
start + dest_x, y + dest_y,
x - 1 + dest_x, y + dest_y);
start = x;
start_status = status;
}
p += apb->n_channels;
}
color.pixel = start_status ? 0 : 1;
gdk_gc_set_foreground (gc, &color);
gdk_draw_line (bitmap, gc,
start + dest_x, y + dest_y,
x - 1 + dest_x, y + dest_y);
}
gdk_gc_unref (gc);
}
void
gdk_pixbuf_render_to_drawable (GdkPixbuf *pixbuf, GdkDrawable *drawable,
int src_x, int src_y,
int dest_x, int dest_y,
int width, int height,
GdkPixbufAlphaMode alpha_mode,
int alpha_threshold,
GdkRgbDither dither,
int x_dither, int y_dither)
{
ArtPixBuf *apb;
ArtIRect dest_rect, req_rect, area_rect;
GdkBitmap *bitmap;
g_return_if_fail (pixbuf != NULL);
apb = pixbuf->art_pixbuf;
g_return_if_fail (apb->format == ART_PIX_RGB);
g_return_if_fail (apb->n_channels == 3 || apb->n_channels == 4);
g_return_if_fail (apb->bits_per_sample == 8);
g_return_if_fail (drawable != NULL);
g_return_if_fail (src_x >= 0 && src_x + width <= apb->width);
g_return_if_fail (src_y >= 0 && src_y + height <= apb->height);
bitmap = gdk_pixmap_new (NULL, width, height, 1);
}
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