An important point about the colormap. If the source drawable does not have a colormap, a compatible one needs to be provided. If you are capturing contents of a window then GdkWindow::get_colormap() method can be used. realize(); $pm = &new GdkPixmap($window->window, 300, 300); $win = $window->window; $cmap = $window->get_colormap(); $c = $cmap->alloc('orange'); $c1 = $cmap->alloc('white'); $c2 = $cmap->alloc('gray50'); $gc = $win->new_gc(); $gc->foreground = $c; $gc->line_width = 3; gdk::draw_rectangle($pm, $window->style->white_gc, true, 0, 0, 300, 300); gdk::draw_line($pm, $gc, 0, 0, 300, 300); gdk::draw_line($pm, $gc, 0, 300, 300, 0); gdk::draw_arc($pm, $gc, true, 100, 100, 100, 100, 64 * 45, 64 * 90); gdk::draw_arc($pm, $gc, true, 100, 100, 100, 100, 64 * 225, 64 * 90); $pixbuf = gdkpixbuf::get_from_drawable(null, $pm, $cmap, 0, 0, 0, 0, 300, 300); $pixbuf = $pixbuf->composite_color_simple(500, 200, GDK_INTERP_BILINEAR, 200, 8, $c1->pixel, $c2->pixel); // Display pixbuf as before ?>]]>