Le samedi 31 janvier 2009 à 20:11 +0000, Richard Shann a écrit : > The Gdk functions to create bitmaps from data require xbm or xpm data. > (For example gdk_bitmap_create_from_data ()). Why do I not see anything > to create a bitmap from a (b&w) .png image?
There are functions to convert a PNG with transparency (alpha component) to a GdkBitmap according to a threshold. See gdk_pixbuf_render_threshold_alpha() http://library.gnome.org/devel/gdk/stable/gdk-Pixbufs.html#gdk-pixbuf-render-threshold-alpha BTW, here is a function (not tested) adapted from some code I wrote, which should create a GdkBitmap from a GdkPixbuf according to your black and white PNG. Feel free to test and fix it. /* * Author: Yann Droneaud <ydrone...@mandriva.com> * */ GdkBitmap * my_gdk_bitmap_new_from_pixbuf_non_alpha(GdkDrawable *drawable, GdkPixbuf *pixbuf) { int width; int height; int rowstride; guchar *pixels; guint32 pixel; gchar *bitmap_data; int bitmap_rowstride; GdkBitmap *bitmap; g_assert(pixbuf != NULL); g_assert(gdk_pixbuf_get_colorspace(pixbuf) == GDK_COLORSPACE_RGB); g_assert(gdk_pixbuf_get_bits_per_sample(pixbuf) == 8); g_assert(gdk_pixbuf_get_has_alpha(pixbuf)); g_assert(gdk_pixbuf_get_n_channels(pixbuf) == 4); width = gdk_pixbuf_get_width(pixbuf); height = gdk_pixbuf_get_height(pixbuf); rowstride = gdk_pixbuf_get_rowstride(pixbuf); pixels = gdk_pixbuf_get_pixels(pixbuf); /* round to byte boundary */ bitmap_rowbytes = (width + 7) / 8; /* allocate a *cleared* buffer for the bitmap data */ bitmap_data = (gchar *) g_malloc0(bitmap_rowbytes * height); g_assert(bitmap_data != NULL); for(y = 0; y < height; y++) { for(x = 0; x < width; x++) { /* WARNING: use 4 components, 8 bits per component */ pixel = * (guint32 *) &pixels[(y * rowbytes) + (x * 4)]; /* remove alpha component * WARNING: beware of endianess */ pixel &= (guint32) 0xffffff00UL; /* if not black, it should be white */ if (pixel != (guint32)0UL) { bitmap_data[(y * bitmap_rowbytes) + (x / 8)] |= 1 << (x % 8); } } } bitmap = gdk_bitmap_create_from_data(drawable, bitmap_data, width, height); g_free(bitmap_data); return bitmap; } _______________________________________________ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
