#include <X11/Xlib.h>
#include <Imlib2.h>
#include <stdio.h>
#include <string.h>

int main(int argc, char **argv) {
	Display *display;
	XWindowAttributes windowattr;
	Imlib_Image image;
	Imlib_Image icon;
	int windowid, thumbwidth, thumbheight;
	char *imageformat, *imagepath;
	char *iconformat, *iconpath;
	int w, h;

	if ( argc != 5 ) {
		puts("Usage: thumb WindowId ThumbWidth ThumbFile IconFile");
		return 1;
	}
	sscanf(argv[1], "%x", &windowid);
	sscanf(argv[2], "%d", &thumbwidth);
	imagepath = argv[3];
	imageformat = strrchr(argv[3], '.');
	iconpath = argv[4];
	iconformat = strrchr(argv[4], '.');

	if ( (display = XOpenDisplay(NULL)) == NULL ) return 1;
	XGetWindowAttributes(display, windowid, &windowattr);
	thumbheight = (int)((float)windowattr.height /
			((float)windowattr.width/(float)thumbwidth));

	imlib_context_set_anti_alias(1);
	imlib_context_set_display(display);
	imlib_context_set_visual(DefaultVisual(display,
				DefaultScreen(display)));
	imlib_context_set_colormap(DefaultColormap(display,
				DefaultScreen(display)));
	imlib_context_set_drawable(windowid);

	if (4*thumbwidth >= windowattr.width ||
			4*thumbheight >= windowattr.height ) {
		image = imlib_create_image_from_drawable((Pixmap)0, 0, 0,
				windowattr.width, windowattr.height, 1);
		imlib_context_set_image(image);
		image = imlib_create_cropped_scaled_image(0, 0,
				windowattr.width, windowattr.height,
				thumbwidth, thumbheight);
	} else {
		image = imlib_create_scaled_image_from_drawable((Pixmap)0, 0, 0,
				windowattr.width, windowattr.height,
				4*thumbwidth, 4*thumbheight, 1, 1);
		imlib_context_set_image(image);
		image = imlib_create_cropped_scaled_image(0, 0,
				4*thumbwidth, 4*thumbheight,
				thumbwidth, thumbheight);
	}
	icon = imlib_load_image(argv[4]);
	imlib_context_set_image(icon);
	w = imlib_image_get_width();
	h = imlib_image_get_height();
	imlib_context_set_image(image);
	imlib_blend_image_onto_image(   icon, 0,
			0, 0, w, h,
			8, 8, w, h);
	imlib_image_set_format(imageformat + 1);
	imlib_save_image(argv[3]);

	fprintf(stdout, "WindowStyle IconOverride, Icon %s\n", argv[3]);
	return 0;
}