i'm using gtk+-2.0 in C. and i have to write a digit upon my tray icon. i do it such way:
static GdkPixbuf * transform_pixbuf(GdkPixbuf *pixbuf) {
cairo_t *cr;
int width = gdk_pixbuf_get_width(pixbuf);
int height = gdk_pixbuf_get_height(pixbuf);
GdkPixmap *pixmap = gdk_pixmap_new(NULL, width, height, 24);
cr = gdk_cairo_create(pixmap);
gdk_cairo_set_source_pixbuf(cr, pixbuf, 0, 0);
cairo_paint(cr);
cairo_select_font_face (cr, "serif", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_BOLD);
cairo_set_font_size (cr, 15.0);
cairo_set_source_rgb (cr, 1.0, 0, 0);
cairo_move_to (cr, 10, 20);
cairo_show_text (cr, "8");
cairo_destroy(cr);
GdkPixbuf *pixbuf_new = gdk_pixbuf_get_from_drawable(NULL, pixmap, NULL,
0, 0, 0, 0, width, height);
return pixbuf_new;
}
where GdkPixbuf *pixbuf is GdkPixbuf i want to set in tray. i can draw a digit, but the icon's background became "dancing" - 
.
i guess the problem is in gdk_pixmap_new's depth argument, because the icon has 32bit format, but 32 isn't valid argument for this function. in such case i have followin warning and no icon in the tray:
Gdk-WARNING **: Using Cairo rendering requires the drawable argument to have a specified colormap. All windows have a colormap, however, pixmaps only have colormap by default if they were created with a non-NULL window argument. Otherwise a colormap must be set on them with gdk_drawable_set_colormap
Gdk-WARNING **: /build/buildd/gtk+2.0-2.24.4/gdk/gdkpixbuf-drawable.c:1249: Source drawable has no colormap; either pass in a colormap, or set the colormap on the drawable with gdk_drawable_set_colormap()
Suggest me, please...
