/* 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, see <http://www.gnu.org/licenses/>.
*/
/* Trivially ported to Xlib(RGB) by John Harper. */
#include "config.h"
#include "gdk-pixbuf-xlib-private.h"
/**
* SECTION:gdk-pixbuf-xlib-rendering
* @Short_description: Rendering a pixbuf to an X drawable.
* @Title: Xlib Rendering
*
* The &gdk-pixbuf; Xlib library provides several convenience
* functions to render pixbufs to X drawables. It uses XlibRGB to
* render the image data.
*
*
* These functions are analogous to those for the GDK version of
* &gdk-pixbuf;.
*/
/**
* gdk_pixbuf_xlib_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 rectangular portion of 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_xlib_render_threshold_alpha (GdkPixbuf *pixbuf, Pixmap bitmap,
int src_x, int src_y,
int dest_x, int dest_y,
int width, int height,
int alpha_threshold)
{
GC gc;
XColor color;
int x, y;
guchar *p;
int start, start_status;
int status;
XGCValues gcv;
g_return_if_fail (pixbuf != NULL);
g_return_if_fail (gdk_pixbuf_get_colorspace (pixbuf) == GDK_COLORSPACE_RGB);
g_return_if_fail (gdk_pixbuf_get_n_channels (pixbuf) == 3 || gdk_pixbuf_get_n_channels (pixbuf) == 4);
g_return_if_fail (gdk_pixbuf_get_bits_per_sample (pixbuf) == 8);
g_return_if_fail (bitmap != 0);
g_return_if_fail (width >= 0 && height >= 0);
g_return_if_fail (src_x >= 0 && src_x + width <= gdk_pixbuf_get_width (pixbuf));
g_return_if_fail (src_y >= 0 && src_y + height <= gdk_pixbuf_get_height (pixbuf));
g_return_if_fail (alpha_threshold >= 0 && alpha_threshold <= 255);
if (width == 0 || height == 0)
return;
gc = XCreateGC (gdk_pixbuf_dpy, bitmap, 0, &gcv);
if (!gdk_pixbuf_get_has_alpha (pixbuf)) {
color.pixel = (alpha_threshold == 255) ? 0 : 1;
XSetForeground (gdk_pixbuf_dpy, gc, color.pixel);
XFillRectangle (gdk_pixbuf_dpy, bitmap, gc,
dest_x, dest_y, width, height);
XFreeGC (gdk_pixbuf_dpy, gc);
return;
}
color.pixel = 0;
XSetForeground (gdk_pixbuf_dpy, gc, color.pixel);
XFillRectangle (gdk_pixbuf_dpy, bitmap, gc,
dest_x, dest_y, width, height);
color.pixel = 1;
XSetForeground (gdk_pixbuf_dpy, gc, color.pixel);
for (y = 0; y < height; y++) {
p = (gdk_pixbuf_get_pixels (pixbuf) + (y + src_y) * gdk_pixbuf_get_rowstride (pixbuf) + src_x * gdk_pixbuf_get_n_channels (pixbuf)
+ gdk_pixbuf_get_n_channels (pixbuf) - 1);
start = 0;
start_status = *p < alpha_threshold;
for (x = 0; x < width; x++) {
status = *p < alpha_threshold;
if (status != start_status) {
if (!start_status)
XDrawLine (gdk_pixbuf_dpy, bitmap, gc,
start + dest_x, y + dest_y,
x - 1 + dest_x, y + dest_y);
start = x;
start_status = status;
}
p += gdk_pixbuf_get_n_channels (pixbuf);
}
if (!start_status)
XDrawLine (gdk_pixbuf_dpy, bitmap, gc,
start + dest_x, y + dest_y,
x - 1 + dest_x, y + dest_y);
}
XFreeGC (gdk_pixbuf_dpy, gc);
}
/* Creates a buffer by stripping the alpha channel of a pixbuf */
static guchar *
remove_alpha (GdkPixbuf *pixbuf, int x, int y, int width, int height, int *rowstride)
{
guchar *buf;
int xx, yy;
guchar *src, *dest;
g_assert (gdk_pixbuf_get_n_channels (pixbuf) == 4);
g_assert (gdk_pixbuf_get_has_alpha (pixbuf));
g_assert (width > 0 && height > 0);
g_assert (x >= 0 && x + width <= gdk_pixbuf_get_width (pixbuf));
g_assert (y >= 0 && y + height <= gdk_pixbuf_get_height (pixbuf));
*rowstride = 4 * ((width * 3 + 3) / 4);
buf = g_new (guchar, *rowstride * height);
for (yy = 0; yy < height; yy++) {
src = gdk_pixbuf_get_pixels (pixbuf) + gdk_pixbuf_get_rowstride (pixbuf) * (yy + y) + x * gdk_pixbuf_get_n_channels (pixbuf);
dest = buf + *rowstride * yy;
for (xx = 0; xx < width; xx++) {
*dest++ = *src++;
*dest++ = *src++;
*dest++ = *src++;
src++;
}
}
return buf;
}
/**
* gdk_pixbuf_xlib_render_to_drawable:
* @pixbuf: A pixbuf.
* @drawable: Destination drawable.
* @gc: GC used for rendering.
* @src_x: Source X coordinate within pixbuf.
* @src_y: Source Y coordinate within pixbuf.
* @dest_x: Destination X coordinate within drawable.
* @dest_y: Destination Y coordinate within drawable.
* @width: Width of region to render, in pixels.
* @height: Height of region to render, in pixels.
* @dither: Dithering mode for XlibRGB.
* @x_dither: X offset for dither.
* @y_dither: Y offset for dither.
*
* Renders a rectangular portion of a pixbuf to a drawable while using the
* specified GC. This is done using XlibRGB, so the specified drawable must
* have the XlibRGB visual and colormap. Note that this function will ignore
* the opacity information for images with an alpha channel; the GC must already
* have the clipping mask set if you want transparent regions to show through.
*
* For an explanation of dither offsets, see the XlibRGB documentation. In
* brief, the dither offset is important when re-rendering partial regions of an
* image to a rendered version of the full image, or for when the offsets to a
* base position change, as in scrolling. The dither matrix has to be shifted
* for consistent visual results. If you do not have any of these cases, the
* dither offsets can be both zero.
**/
void
gdk_pixbuf_xlib_render_to_drawable (GdkPixbuf *pixbuf,
Drawable drawable, GC gc,
int src_x, int src_y,
int dest_x, int dest_y,
int width, int height,
XlibRgbDither dither,
int x_dither, int y_dither)
{
guchar *buf;
int rowstride;
g_return_if_fail (pixbuf != NULL);
g_return_if_fail (gdk_pixbuf_get_colorspace (pixbuf) == GDK_COLORSPACE_RGB);
g_return_if_fail (gdk_pixbuf_get_n_channels (pixbuf) == 3 || gdk_pixbuf_get_n_channels (pixbuf) == 4);
g_return_if_fail (gdk_pixbuf_get_bits_per_sample (pixbuf) == 8);
g_return_if_fail (drawable != 0);
g_return_if_fail (gc != 0);
g_return_if_fail (width >= 0 && height >= 0);
g_return_if_fail (src_x >= 0 && src_x + width <= gdk_pixbuf_get_width (pixbuf));
g_return_if_fail (src_y >= 0 && src_y + height <= gdk_pixbuf_get_height (pixbuf));
if (width == 0 || height == 0)
return;
/* This will have to be modified once we support other image types.
* Also, GdkRGB does not have gdk_draw_rgb_32_image_dithalign(), so we
* have to pack the buffer first. Sigh.
*/
if (gdk_pixbuf_get_has_alpha (pixbuf))
buf = remove_alpha (pixbuf, src_x, src_y, width, height, &rowstride);
else {
buf = gdk_pixbuf_get_pixels (pixbuf) + src_y * gdk_pixbuf_get_rowstride (pixbuf) + src_x * 3;
rowstride = gdk_pixbuf_get_rowstride (pixbuf);
}
xlib_draw_rgb_image_dithalign (drawable, gc,
dest_x, dest_y,
width, height,
dither,
buf, rowstride,
x_dither, y_dither);
if (gdk_pixbuf_get_has_alpha (pixbuf))
g_free (buf);
}
/**
* gdk_pixbuf_xlib_render_to_drawable_alpha:
* @pixbuf: A pixbuf.
* @drawable: Destination drawable.
* @src_x: Source X coordinate within pixbuf.
* @src_y: Source Y coordinates within pixbuf.
* @dest_x: Destination X coordinate within drawable.
* @dest_y: Destination Y coordinate within drawable.
* @width: Width of region to render, in pixels.
* @height: Height of region to render, in pixels.
* @alpha_mode: If the image does not have opacity information, this is ignored.
* Otherwise, specifies how to handle transparency when rendering.
* @alpha_threshold: If the image does have opacity information and @alpha_mode
* is GDK_PIXBUF_ALPHA_BILEVEL, specifies the threshold value for opacity
* values.
* @dither: Dithering mode for XlibRGB.
* @x_dither: X offset for dither.
* @y_dither: Y offset for dither.
*
* Renders a rectangular portion of a pixbuf to a drawable. This is done using
* XlibRGB, so the specified drawable must have the XlibRGB visual and colormap.
*
* When used with #GDK_PIXBUF_ALPHA_BILEVEL, this function has to create a bitmap
* out of the thresholded alpha channel of the image and, it has to set this
* bitmap as the clipping mask for the GC used for drawing. This can be a
* significant performance penalty depending on the size and the complexity of
* the alpha channel of the image. If performance is crucial, consider handling
* the alpha channel yourself (possibly by caching it in your application) and
* using gdk_pixbuf_xlib_render_to_drawable() or GdkRGB directly instead.
**/
void
gdk_pixbuf_xlib_render_to_drawable_alpha (GdkPixbuf *pixbuf, Drawable drawable,
int src_x, int src_y,
int dest_x, int dest_y,
int width, int height,
GdkPixbufAlphaMode alpha_mode,
int alpha_threshold,
XlibRgbDither dither,
int x_dither, int y_dither)
{
Pixmap bitmap = 0;
GC gc;
XGCValues gcv;
g_return_if_fail (pixbuf != NULL);
g_return_if_fail (gdk_pixbuf_get_colorspace (pixbuf) == GDK_COLORSPACE_RGB);
g_return_if_fail (gdk_pixbuf_get_n_channels (pixbuf) == 3 || gdk_pixbuf_get_n_channels (pixbuf) == 4);
g_return_if_fail (gdk_pixbuf_get_bits_per_sample (pixbuf) == 8);
g_return_if_fail (drawable != 0);
g_return_if_fail (width >= 0 && height >= 0);
g_return_if_fail (src_x >= 0 && src_x + width <= gdk_pixbuf_get_width (pixbuf));
g_return_if_fail (src_y >= 0 && src_y + height <= gdk_pixbuf_get_height (pixbuf));
if (width == 0 || height == 0)
return;
gc = XCreateGC (gdk_pixbuf_dpy, drawable, 0, &gcv);
if (gdk_pixbuf_get_has_alpha (pixbuf)) {
/* Right now we only support GDK_PIXBUF_ALPHA_BILEVEL, so we
* unconditionally create the clipping mask.
*/
bitmap = XCreatePixmap (gdk_pixbuf_dpy,
RootWindow (gdk_pixbuf_dpy,
gdk_pixbuf_screen),
width, height, 1);
gdk_pixbuf_xlib_render_threshold_alpha (pixbuf, bitmap,
src_x, src_y,
0, 0,
width, height,
alpha_threshold);
XSetClipMask (gdk_pixbuf_dpy, gc, bitmap);
XSetClipOrigin (gdk_pixbuf_dpy, gc, dest_x, dest_y);
}
gdk_pixbuf_xlib_render_to_drawable (pixbuf, drawable, gc,
src_x, src_y,
dest_x, dest_y,
width, height,
dither,
x_dither, y_dither);
if (bitmap)
XFreePixmap (gdk_pixbuf_dpy, bitmap);
XFreeGC (gdk_pixbuf_dpy, gc);
}
/**
* gdk_pixbuf_xlib_render_pixmap_and_mask:
* @pixbuf: A pixbuf.
* @pixmap_return: Return value for the created pixmap.
* @mask_return: Return value for the created mask.
* @alpha_threshold: Threshold value for opacity values.
*
* Creates a pixmap and a mask bitmap which are returned in the @pixmap_return
* and @mask_return arguments, respectively, and renders a pixbuf and its
* corresponding tresholded alpha mask to them. This is merely a convenience
* function; applications that need to render pixbufs with dither offsets or to
* given drawables should use gdk_pixbuf_xlib_render_to_drawable_alpha() or
* gdk_pixbuf_xlib_render_to_drawable(), and
* gdk_pixbuf_xlib_render_threshold_alpha().
*
* If the pixbuf does not have an alpha channel, then *@mask_return will be set
* to None.
**/
void
gdk_pixbuf_xlib_render_pixmap_and_mask (GdkPixbuf *pixbuf,
Pixmap *pixmap_return,
Pixmap *mask_return,
int alpha_threshold)
{
g_return_if_fail (pixbuf != NULL);
if (pixmap_return) {
GC gc;
XGCValues gcv;
*pixmap_return = XCreatePixmap (gdk_pixbuf_dpy,
RootWindow (gdk_pixbuf_dpy,
gdk_pixbuf_screen),
gdk_pixbuf_get_width (pixbuf),
gdk_pixbuf_get_height (pixbuf),
xlib_rgb_get_depth ());
gc = XCreateGC (gdk_pixbuf_dpy, *pixmap_return, 0, &gcv);
gdk_pixbuf_xlib_render_to_drawable (pixbuf, *pixmap_return, gc,
0, 0, 0, 0,
gdk_pixbuf_get_width (pixbuf),
gdk_pixbuf_get_height (pixbuf),
XLIB_RGB_DITHER_NORMAL,
0, 0);
XFreeGC (gdk_pixbuf_dpy, gc);
}
if (mask_return) {
if (gdk_pixbuf_get_has_alpha (pixbuf)) {
*mask_return = XCreatePixmap (gdk_pixbuf_dpy,
RootWindow (gdk_pixbuf_dpy,
gdk_pixbuf_screen),
gdk_pixbuf_get_width (pixbuf),
gdk_pixbuf_get_height (pixbuf), 1);
gdk_pixbuf_xlib_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 = 0;
}
}