private Gdk.Pixbuf HistogramGraph(IImage img) { IImage graph = new IImage(BPP.Grayscale, img.W, 260); graph.Clear((byte)255); for (int i = 0; i < img.W; i++) { int hval = (byte)img[i, 0]; for (int j = 0; j < hval; j++) { graph[i, 255 - j] = (byte)0; } for (int j = 0; j < 3; j++) { graph[i, 259 - j] = (byte)((i * 255) / img.W); } } return(graph.CreatePixbuf()); }