forked from AuroraMiddleware/gtk
32b708985d
Wed Sep 19 16:12:16 2001 Owen Taylor <otaylor@redhat.com> * gdk/gdkpixbuf-render.c: Allow -1 for width/height to mean "width/height of pixbuf" (Patch from Matthias Clasen, #59723)
536 lines
17 KiB
C
536 lines
17 KiB
C
/* GdkPixbuf library - Rendering functions
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*
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* Copyright (C) 1999 The Free Software Foundation
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*
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* Author: Federico Mena-Quintero <federico@gimp.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/gdk.h>
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#include "gdk-pixbuf-private.h"
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#include "gdkpixbuf.h"
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/**
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* gdk_pixbuf_render_threshold_alpha:
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* @pixbuf: A pixbuf.
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* @bitmap: Bitmap where the bilevel mask will be painted to.
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* @src_x: Source X coordinate.
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* @src_y: source Y coordinate.
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* @dest_x: Destination X coordinate.
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* @dest_y: Destination Y coordinate.
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* @width: Width of region to threshold, or -1 to use pixbuf width
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* @height: Height of region to threshold, or -1 to use pixbuf height
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* @alpha_threshold: Opacity values below this will be painted as zero; all
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* other values will be painted as one.
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*
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* Takes the opacity values in a rectangular portion of a pixbuf and thresholds
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* them to produce a bi-level alpha mask that can be used as a clipping mask for
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* a drawable.
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*
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**/
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void
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gdk_pixbuf_render_threshold_alpha (GdkPixbuf *pixbuf,
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GdkBitmap *bitmap,
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int src_x, int src_y,
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int dest_x, int dest_y,
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int width, int height,
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int alpha_threshold)
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{
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GdkGC *gc;
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GdkColor color;
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int x, y;
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guchar *p;
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int start, start_status;
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int status;
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g_return_if_fail (GDK_IS_PIXBUF (pixbuf));
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g_return_if_fail (pixbuf->colorspace == GDK_COLORSPACE_RGB);
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g_return_if_fail (pixbuf->n_channels == 3 || pixbuf->n_channels == 4);
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g_return_if_fail (pixbuf->bits_per_sample == 8);
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if (width == -1)
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width = pixbuf->width;
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if (height == -1)
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height = pixbuf->height;
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g_return_if_fail (bitmap != NULL);
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g_return_if_fail (width >= 0 && height >= 0);
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g_return_if_fail (src_x >= 0 && src_x + width <= pixbuf->width);
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g_return_if_fail (src_y >= 0 && src_y + height <= pixbuf->height);
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g_return_if_fail (alpha_threshold >= 0 && alpha_threshold <= 255);
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if (width == 0 || height == 0)
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return;
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gc = gdk_gc_new (bitmap);
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if (!pixbuf->has_alpha)
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{
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color.pixel = (alpha_threshold == 255) ? 0 : 1;
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gdk_gc_set_foreground (gc, &color);
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gdk_draw_rectangle (bitmap, gc, TRUE, dest_x, dest_y, width, height);
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gdk_gc_unref (gc);
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return;
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}
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color.pixel = 0;
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gdk_gc_set_foreground (gc, &color);
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gdk_draw_rectangle (bitmap, gc, TRUE, dest_x, dest_y, width, height);
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color.pixel = 1;
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gdk_gc_set_foreground (gc, &color);
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for (y = 0; y < height; y++)
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{
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p = (pixbuf->pixels + (y + src_y) * pixbuf->rowstride + src_x * pixbuf->n_channels
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+ pixbuf->n_channels - 1);
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start = 0;
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start_status = *p < alpha_threshold;
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for (x = 0; x < width; x++)
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{
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status = *p < alpha_threshold;
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if (status != start_status)
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{
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if (!start_status)
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gdk_draw_line (bitmap, gc,
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start + dest_x, y + dest_y,
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x - 1 + dest_x, y + dest_y);
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start = x;
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start_status = status;
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}
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p += pixbuf->n_channels;
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}
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if (!start_status)
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gdk_draw_line (bitmap, gc,
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start + dest_x, y + dest_y,
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x - 1 + dest_x, y + dest_y);
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}
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gdk_gc_unref (gc);
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}
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/**
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* gdk_pixbuf_render_to_drawable:
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* @pixbuf: A pixbuf.
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* @drawable: Destination drawable.
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* @gc: GC used for rendering.
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* @src_x: Source X coordinate within pixbuf.
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* @src_y: Source Y coordinate within pixbuf.
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* @dest_x: Destination X coordinate within drawable.
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* @dest_y: Destination Y coordinate within drawable.
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* @width: Width of region to render, in pixels, or -1 to use pixbuf width
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* @height: Height of region to render, in pixels, or -1 to use pixbuf height
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* @dither: Dithering mode for GdkRGB.
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* @x_dither: X offset for dither.
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* @y_dither: Y offset for dither.
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*
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* Renders a rectangular portion of a pixbuf to a drawable while using the
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* specified GC. This is done using GdkRGB, so the specified drawable must have
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* the GdkRGB visual and colormap. Note that this function will ignore the
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* opacity information for images with an alpha channel; the GC must already
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* have the clipping mask set if you want transparent regions to show through.
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*
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* For an explanation of dither offsets, see the GdkRGB documentation. In
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* brief, the dither offset is important when re-rendering partial regions of an
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* image to a rendered version of the full image, or for when the offsets to a
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* base position change, as in scrolling. The dither matrix has to be shifted
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* for consistent visual results. If you do not have any of these cases, the
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* dither offsets can be both zero.
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**/
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void
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gdk_pixbuf_render_to_drawable (GdkPixbuf *pixbuf,
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GdkDrawable *drawable,
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GdkGC *gc,
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int src_x, int src_y,
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int dest_x, int dest_y,
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int width, int height,
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GdkRgbDither dither,
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int x_dither, int y_dither)
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{
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int rowstride;
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guchar *buf;
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g_return_if_fail (GDK_IS_PIXBUF (pixbuf));
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g_return_if_fail (pixbuf->colorspace == GDK_COLORSPACE_RGB);
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g_return_if_fail (pixbuf->n_channels == 3 || pixbuf->n_channels == 4);
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g_return_if_fail (pixbuf->bits_per_sample == 8);
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g_return_if_fail (drawable != NULL);
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g_return_if_fail (gc != NULL);
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if (width == -1)
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width = pixbuf->width;
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if (height == -1)
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height = pixbuf->height;
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g_return_if_fail (width >= 0 && height >= 0);
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g_return_if_fail (src_x >= 0 && src_x + width <= pixbuf->width);
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g_return_if_fail (src_y >= 0 && src_y + height <= pixbuf->height);
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if (width == 0 || height == 0)
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return;
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/* This will have to be modified once we support other image types.
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*/
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if (pixbuf->n_channels == 4)
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{
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buf = pixbuf->pixels + src_y * pixbuf->rowstride + src_x * 4;
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rowstride = pixbuf->rowstride;
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gdk_draw_rgb_32_image_dithalign (drawable, gc,
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dest_x, dest_y,
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width, height,
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dither,
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buf, rowstride,
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x_dither, y_dither);
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}
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else /* n_channels == 3 */
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{
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buf = pixbuf->pixels + src_y * pixbuf->rowstride + src_x * 3;
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rowstride = pixbuf->rowstride;
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gdk_draw_rgb_image_dithalign (drawable, gc,
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dest_x, dest_y,
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width, height,
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dither,
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buf, rowstride,
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x_dither, y_dither);
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}
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}
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/**
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* gdk_pixbuf_render_to_drawable_alpha:
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* @pixbuf: A pixbuf.
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* @drawable: Destination drawable.
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* @src_x: Source X coordinate within pixbuf.
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* @src_y: Source Y coordinates within pixbuf.
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* @dest_x: Destination X coordinate within drawable.
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* @dest_y: Destination Y coordinate within drawable.
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* @width: Width of region to render, in pixels, or -1 to use pixbuf width.
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* @height: Height of region to render, in pixels, or -1 to use pixbuf height.
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* @alpha_mode: If the image does not have opacity information, this is ignored.
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* Otherwise, specifies how to handle transparency when rendering.
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* @alpha_threshold: If the image does have opacity information and @alpha_mode
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* is GDK_PIXBUF_ALPHA_BILEVEL, specifies the threshold value for opacity
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* values.
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* @dither: Dithering mode for GdkRGB.
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* @x_dither: X offset for dither.
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* @y_dither: Y offset for dither.
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*
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* Renders a rectangular portion of a pixbuf to a drawable. This is done using
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* GdkRGB, so the specified drawable must have the GdkRGB visual and colormap.
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*
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* When used with #GDK_PIXBUF_ALPHA_BILEVEL, this function has to create a bitmap
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* out of the thresholded alpha channel of the image and, it has to set this
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* bitmap as the clipping mask for the GC used for drawing. This can be a
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* significant performance penalty depending on the size and the complexity of
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* the alpha channel of the image. If performance is crucial, consider handling
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* the alpha channel yourself (possibly by caching it in your application) and
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* using gdk_pixbuf_render_to_drawable() or GdkRGB directly instead.
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*
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* The #GDK_PIXBUF_ALPHA_FULL mode involves round trips to the X
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* server, and may also be somewhat slow in its current implementation
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* (though in the future it could be made significantly faster, in
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* principle).
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**/
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void
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gdk_pixbuf_render_to_drawable_alpha (GdkPixbuf *pixbuf,
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GdkDrawable *drawable,
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int src_x, int src_y,
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int dest_x, int dest_y,
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int width, int height,
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GdkPixbufAlphaMode alpha_mode,
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int alpha_threshold,
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GdkRgbDither dither,
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int x_dither, int y_dither)
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{
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GdkBitmap *bitmap = NULL;
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GdkGC *gc;
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GdkPixbuf *composited = NULL;
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gint dwidth, dheight;
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GdkRegion *clip;
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GdkRegion *drect;
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GdkRectangle tmp_rect;
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g_return_if_fail (GDK_IS_PIXBUF (pixbuf));
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g_return_if_fail (pixbuf->colorspace == GDK_COLORSPACE_RGB);
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g_return_if_fail (pixbuf->n_channels == 3 || pixbuf->n_channels == 4);
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g_return_if_fail (pixbuf->bits_per_sample == 8);
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g_return_if_fail (drawable != NULL);
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if (width == -1)
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width = pixbuf->width;
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if (height == -1)
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height = pixbuf->height;
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g_return_if_fail (width >= 0 && height >= 0);
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g_return_if_fail (src_x >= 0 && src_x + width <= pixbuf->width);
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g_return_if_fail (src_y >= 0 && src_y + height <= pixbuf->height);
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/* Clip to the drawable; this is required for get_from_drawable() so
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* can't be done implicitly
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*/
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if (dest_x < 0)
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{
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src_x -= dest_x;
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width += dest_x;
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dest_x = 0;
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}
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if (dest_y < 0)
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{
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src_y -= dest_y;
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height += dest_y;
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dest_y = 0;
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}
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gdk_drawable_get_size (drawable, &dwidth, &dheight);
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if ((dest_x + width) > dwidth)
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width = dwidth - dest_x;
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if ((dest_y + height) > dheight)
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height = dheight - dest_y;
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if (width <= 0 || height <= 0)
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return;
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/* Clip to the clip region; this avoids getting more
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* image data from the server than we need to.
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*/
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tmp_rect.x = dest_x;
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tmp_rect.y = dest_y;
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tmp_rect.width = width;
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tmp_rect.height = height;
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drect = gdk_region_rectangle (&tmp_rect);
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clip = gdk_drawable_get_clip_region (drawable);
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gdk_region_intersect (drect, clip);
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gdk_region_get_clipbox (drect, &tmp_rect);
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gdk_region_destroy (drect);
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gdk_region_destroy (clip);
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if (tmp_rect.width == 0 ||
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tmp_rect.height == 0)
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return;
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/* Actually draw */
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gc = gdk_gc_new (drawable);
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if (pixbuf->has_alpha)
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{
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if (alpha_mode == GDK_PIXBUF_ALPHA_FULL)
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{
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GdkPixbuf *sub = NULL;
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composited = gdk_pixbuf_get_from_drawable (NULL,
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drawable,
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NULL,
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dest_x, dest_y,
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0, 0,
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width, height);
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if (composited)
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{
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if (src_x != 0 || src_y != 0)
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{
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sub = gdk_pixbuf_new_subpixbuf (pixbuf, src_x, src_y,
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width, height);
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}
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gdk_pixbuf_composite (sub ? sub : pixbuf,
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composited,
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0, 0,
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width, height,
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0, 0,
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1.0, 1.0,
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GDK_INTERP_BILINEAR,
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255);
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if (sub)
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g_object_unref (G_OBJECT (sub));
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}
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else
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alpha_mode = GDK_PIXBUF_ALPHA_BILEVEL; /* fall back */
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}
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if (alpha_mode == GDK_PIXBUF_ALPHA_BILEVEL)
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{
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bitmap = gdk_pixmap_new (NULL, width, height, 1);
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gdk_pixbuf_render_threshold_alpha (pixbuf, bitmap,
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src_x, src_y,
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0, 0,
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width, height,
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alpha_threshold);
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gdk_gc_set_clip_mask (gc, bitmap);
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gdk_gc_set_clip_origin (gc, dest_x, dest_y);
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}
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}
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if (composited)
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{
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gdk_pixbuf_render_to_drawable (composited,
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drawable, gc,
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0, 0,
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dest_x, dest_y,
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width, height,
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dither,
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x_dither, y_dither);
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}
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else
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{
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gdk_pixbuf_render_to_drawable (pixbuf,
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drawable, gc,
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src_x, src_y,
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dest_x, dest_y,
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width, height,
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dither,
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x_dither, y_dither);
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}
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if (bitmap)
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gdk_bitmap_unref (bitmap);
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if (composited)
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g_object_unref (G_OBJECT (composited));
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gdk_gc_unref (gc);
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}
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/**
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* gdk_pixbuf_render_pixmap_and_mask:
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* @pixbuf: A pixbuf.
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* @pixmap_return: Return value for the created pixmap.
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* @mask_return: Return value for the created mask.
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* @alpha_threshold: Threshold value for opacity values.
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*
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* Creates a pixmap and a mask bitmap which are returned in the @pixmap_return
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* and @mask_return arguments, respectively, and renders a pixbuf and its
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* corresponding thresholded alpha mask to them. This is merely a convenience
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* function; applications that need to render pixbufs with dither offsets or to
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* given drawables should use gdk_pixbuf_render_to_drawable_alpha() or
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* gdk_pixbuf_render_to_drawable(), and gdk_pixbuf_render_threshold_alpha().
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*
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* The pixmap that is created is created for the colormap returned
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* by gdk_rgb_get_colormap(). You normally will want to instead use
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* the actual colormap for a widget, and use
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* gdk_pixbuf_render_pixmap_and_mask_for_colormap.
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*
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* If the pixbuf does not have an alpha channel, then *@mask_return will be set
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* to NULL.
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**/
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void
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gdk_pixbuf_render_pixmap_and_mask (GdkPixbuf *pixbuf,
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GdkPixmap **pixmap_return,
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GdkBitmap **mask_return,
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int alpha_threshold)
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{
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gdk_pixbuf_render_pixmap_and_mask_for_colormap (pixbuf,
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gdk_rgb_get_colormap (),
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pixmap_return, mask_return,
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alpha_threshold);
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}
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/**
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* gdk_pixbuf_render_pixmap_and_mask_for_colormap:
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* @pixbuf: A pixbuf.
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* @colormap: A #GdkColormap
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* @pixmap_return: Return value for the created pixmap.
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* @mask_return: Return value for the created mask.
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* @alpha_threshold: Threshold value for opacity values.
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*
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* Creates a pixmap and a mask bitmap which are returned in the @pixmap_return
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* and @mask_return arguments, respectively, and renders a pixbuf and its
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* corresponding tresholded alpha mask to them. This is merely a convenience
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* function; applications that need to render pixbufs with dither offsets or to
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* given drawables should use gdk_pixbuf_render_to_drawable_alpha() or
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* gdk_pixbuf_render_to_drawable(), and gdk_pixbuf_render_threshold_alpha().
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*
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* The pixmap that is created uses the #GdkColormap specified by @colormap.
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* This colormap must match the colormap of the window where the pixmap
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* will eventually be used or an error will result.
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*
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||
* If the pixbuf does not have an alpha channel, then *@mask_return will be set
|
||
* to NULL.
|
||
**/
|
||
void
|
||
gdk_pixbuf_render_pixmap_and_mask_for_colormap (GdkPixbuf *pixbuf,
|
||
GdkColormap *colormap,
|
||
GdkPixmap **pixmap_return,
|
||
GdkBitmap **mask_return,
|
||
int alpha_threshold)
|
||
{
|
||
g_return_if_fail (pixbuf != NULL);
|
||
|
||
if (pixmap_return)
|
||
{
|
||
GdkGC *gc;
|
||
|
||
*pixmap_return = gdk_pixmap_new (NULL, gdk_pixbuf_get_width (pixbuf), gdk_pixbuf_get_height (pixbuf),
|
||
gdk_colormap_get_visual (colormap)->depth);
|
||
gdk_drawable_set_colormap (GDK_DRAWABLE (*pixmap_return),
|
||
colormap);
|
||
gc = gdk_gc_new (*pixmap_return);
|
||
gdk_pixbuf_render_to_drawable (pixbuf, *pixmap_return, gc,
|
||
0, 0, 0, 0,
|
||
gdk_pixbuf_get_width (pixbuf), gdk_pixbuf_get_height (pixbuf),
|
||
GDK_RGB_DITHER_NORMAL,
|
||
0, 0);
|
||
gdk_gc_unref (gc);
|
||
}
|
||
|
||
if (mask_return)
|
||
{
|
||
if (gdk_pixbuf_get_has_alpha (pixbuf))
|
||
{
|
||
*mask_return = gdk_pixmap_new (NULL, gdk_pixbuf_get_width (pixbuf), gdk_pixbuf_get_height (pixbuf), 1);
|
||
|
||
gdk_pixbuf_render_threshold_alpha (pixbuf, *mask_return,
|
||
0, 0, 0, 0,
|
||
gdk_pixbuf_get_width (pixbuf), gdk_pixbuf_get_height (pixbuf),
|
||
alpha_threshold);
|
||
}
|
||
else
|
||
*mask_return = NULL;
|
||
}
|
||
}
|
||
|
||
|