/* GdkPixbuf library - Rendering functions * * Copyright (C) 1999 The Free Software Foundation * * Author: Federico Mena-Quintero * * 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 #include #include "gdkpixbuf.h" #include "gdkscreen.h" #include "gdkinternals.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, or -1 to use pixbuf width * @height: Height of region to threshold, or -1 to use pixbuf height * @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_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) { cairo_t *cr; int x, y; guchar *p; int start, start_status; int status; 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); if (width == -1) width = gdk_pixbuf_get_width (pixbuf); if (height == -1) height = gdk_pixbuf_get_height (pixbuf); g_return_if_fail (bitmap != NULL); 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; cr = gdk_cairo_create (bitmap); cairo_rectangle (cr, dest_x, dest_y, width, height); cairo_clip (cr); if (!gdk_pixbuf_get_has_alpha (pixbuf)) { cairo_set_source_rgba (cr, 0, 0, 0, alpha_threshold == 255 ? 0 : 1); cairo_paint (cr); cairo_destroy (cr); return; } cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR); cairo_paint (cr); cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE); if (alpha_threshold == 128) { gdk_cairo_set_source_pixbuf (cr, pixbuf, src_x - dest_x, src_y - dest_y); cairo_paint (cr); cairo_destroy (cr); return; } cairo_set_source_rgb (cr, 0, 0, 0); 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) cairo_rectangle (cr, start + dest_x, y + dest_y, x + dest_x, y + dest_y + 1); start = x; start_status = status; } p += gdk_pixbuf_get_n_channels (pixbuf); } if (!start_status) cairo_rectangle (cr, start + dest_x, y + dest_y, x + dest_x, y + dest_y + 1); } cairo_fill (cr); cairo_destroy (cr); } /** * gdk_pixbuf_render_pixmap_and_mask: * @pixbuf: A pixbuf. * @pixmap_return: Location to store a pointer to the created pixmap, * or %NULL if the pixmap is not needed. * @mask_return: Location to store a pointer to the created mask, * or %NULL if the mask is not needed. * @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 thresholded 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 Cairo and gdk_pixbuf_render_threshold_alpha(). * * The pixmap that is created is created for the colormap returned * by gdk_colormap_get_system(). You normally will want to instead use * the actual colormap for a widget, and use * gdk_pixbuf_render_pixmap_and_mask_for_colormap(). * * If the pixbuf does not have an alpha channel, then *@mask_return will be set * to %NULL. **/ void gdk_pixbuf_render_pixmap_and_mask (GdkPixbuf *pixbuf, GdkPixmap **pixmap_return, GdkBitmap **mask_return, int alpha_threshold) { gdk_pixbuf_render_pixmap_and_mask_for_colormap (pixbuf, gdk_colormap_get_system (), pixmap_return, mask_return, alpha_threshold); } static GdkPixbuf * remove_alpha_channel (GdkPixbuf *orig) { GdkPixbuf *pixbuf; unsigned int x, y, width, height, stride; unsigned char *data; if (!gdk_pixbuf_get_has_alpha (orig)) return g_object_ref (orig); pixbuf = gdk_pixbuf_copy (orig); width = gdk_pixbuf_get_width (pixbuf); height = gdk_pixbuf_get_height (pixbuf); stride = gdk_pixbuf_get_rowstride (pixbuf); data = gdk_pixbuf_get_pixels (pixbuf); for (y = 0; y < height; y++) { for (x = 0; x < width; x++) { data[x * 4 + 3] = 0xFF; } data += stride; } return pixbuf; } /** * gdk_pixbuf_render_pixmap_and_mask_for_colormap: * @pixbuf: A pixbuf. * @colormap: A #GdkColormap * @pixmap_return: Location to store a pointer to the created pixmap, * or %NULL if the pixmap is not needed. * @mask_return: Location to store a pointer to the created mask, * or %NULL if the mask is not needed. * @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 Cairo and gdk_pixbuf_render_threshold_alpha(). * * The pixmap that is created uses the #GdkColormap specified by @colormap. * This colormap must match the colormap of the window where the pixmap * will eventually be used or an error will result. * * 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) { GdkScreen *screen; g_return_if_fail (GDK_IS_PIXBUF (pixbuf)); g_return_if_fail (GDK_IS_COLORMAP (colormap)); screen = gdk_colormap_get_screen (colormap); if (pixmap_return) { GdkPixbuf *tmp_pixbuf; cairo_t *cr; *pixmap_return = gdk_pixmap_new (gdk_screen_get_root_window (screen), 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); /* If the pixbuf has an alpha channel, using gdk_cairo_set_source_pixbuf() * would give * random pixel values in the area that are within the mask, but semi- * transparent. So we treat the pixbuf like a pixbuf without alpha channel; * see bug #487865. */ tmp_pixbuf = remove_alpha_channel (pixbuf); cr = gdk_cairo_create (*pixmap_return); gdk_cairo_set_source_pixbuf (cr, pixbuf, 0, 0); cairo_paint (cr); cairo_destroy (cr); g_object_unref (tmp_pixbuf); } if (mask_return) { if (gdk_pixbuf_get_has_alpha (pixbuf)) { *mask_return = gdk_pixmap_new (gdk_screen_get_root_window (screen), 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; } }