1 files changed, 398 insertions, 0 deletions
diff --git a/contrib/gdk-pixbuf-xlib/gdk-pixbuf-xlib-render.c b/contrib/gdk-pixbuf-xlib/gdk-pixbuf-xlib-render.c
new file mode 100644
index 000000000..b6a26ebf3
--- /dev/null
+++ b/contrib/gdk-pixbuf-xlib/gdk-pixbuf-xlib-render.c
@@ -0,0 +1,398 @@
+/* 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.
+ */
+
+/* Trivially ported to Xlib(RGB) by John Harper. */
+
+#include <config.h>
+#include "gdk-pixbuf-private.h"
+#include "gdk-pixbuf-xlib-private.h"
+
+
+
+/**
+ * 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 (pixbuf->colorspace == GDK_COLORSPACE_RGB);
+	g_return_if_fail (pixbuf->n_channels == 3 || pixbuf->n_channels == 4);
+	g_return_if_fail (pixbuf->bits_per_sample == 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 <= pixbuf->width);
+	g_return_if_fail (src_y >= 0 && src_y + height <= pixbuf->height);
+
+	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 (!pixbuf->has_alpha) {
+		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 = (pixbuf->pixels + (y + src_y) * pixbuf->rowstride + src_x * pixbuf->n_channels
+		     + pixbuf->n_channels - 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 += pixbuf->n_channels;
+		}
+
+		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 (pixbuf->n_channels == 4);
+	g_assert (pixbuf->has_alpha);
+	g_assert (width > 0 && height > 0);
+	g_assert (x >= 0 && x + width <= pixbuf->width);
+	g_assert (y >= 0 && y + height <= pixbuf->height);
+
+	*rowstride = 4 * ((width * 3 + 3) / 4);
+
+	buf = g_new (guchar, *rowstride * height);
+
+	for (yy = 0; yy < height; yy++) {
+		src = pixbuf->pixels + pixbuf->rowstride * (yy + y) + x * pixbuf->n_channels;
+		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 (pixbuf->colorspace == GDK_COLORSPACE_RGB);
+	g_return_if_fail (pixbuf->n_channels == 3 || pixbuf->n_channels == 4);
+	g_return_if_fail (pixbuf->bits_per_sample == 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 <= pixbuf->width);
+	g_return_if_fail (src_y >= 0 && src_y + height <= pixbuf->height);
+
+	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 (pixbuf->has_alpha)
+		buf = remove_alpha (pixbuf, src_x, src_y, width, height, &rowstride);
+	else {
+		buf = pixbuf->pixels + src_y * pixbuf->rowstride + src_x * 3;
+		rowstride = pixbuf->rowstride;
+	}
+
+	xlib_draw_rgb_image_dithalign (drawable, gc,
+				       dest_x, dest_y,
+				       width, height,
+				       dither,
+				       buf, rowstride,
+				       x_dither, y_dither);
+
+	if (pixbuf->has_alpha)
+		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 (pixbuf->colorspace == GDK_COLORSPACE_RGB);
+	g_return_if_fail (pixbuf->n_channels == 3 || pixbuf->n_channels == 4);
+	g_return_if_fail (pixbuf->bits_per_sample == 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 <= pixbuf->width);
+	g_return_if_fail (src_y >= 0 && src_y + height <= pixbuf->height);
+
+	if (width == 0 || height == 0)
+		return;
+
+	gc = XCreateGC (gdk_pixbuf_dpy, drawable, 0, &gcv);
+
+	if (pixbuf->has_alpha) {
+		/* 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),
+						pixbuf->width,
+						pixbuf->height,
+						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,
+						    pixbuf->width,
+						    pixbuf->height,
+						    XLIB_RGB_DITHER_NORMAL,
+						    0, 0);
+		XFreeGC (gdk_pixbuf_dpy, gc);
+	}
+
+	if (mask_return) {
+		if (pixbuf->has_alpha) {
+		    *mask_return = XCreatePixmap (gdk_pixbuf_dpy,
+						  RootWindow (gdk_pixbuf_dpy,
+							      gdk_pixbuf_screen),
+						  pixbuf->width,
+						  pixbuf->height, 1);
+		    gdk_pixbuf_xlib_render_threshold_alpha (pixbuf,
+							    *mask_return,
+							    0, 0, 0, 0,
+							    pixbuf->width,
+							    pixbuf->height,
+							    alpha_threshold);
+		} else
+			*mask_return = 0;
+	}
+}