#include <stdio.h>
#include <stdlib.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>

char *wname = "xline";

#define XDIM	300
#define YDIM	300

XPoint points[4] = {
	{ 74, 31029},
	{ 74, 177},
	{ 108, 143},
	{ 108, -384},
};

main(int ac, char **av)
{
	Display *disp;
	Window wind;
	int scr, y;
	unsigned long fg, bg;
	GC gc, gcc;
	XEvent xev;
	XSizeHints hints;
	XWMHints whints;
	XGCValues gcv;
	Pixmap pix;

	if (ac > 1) {
		y = atoi(av[1]);
		if (y != 0)
			points[0].y = y;
	}

	disp = XOpenDisplay(NULL);
	if( disp == NULL ){
		fprintf(stderr, "couldn't open display\n");
		exit(1);
	}

	scr = DefaultScreen(disp);
	bg = WhitePixel(disp, scr);
	fg = BlackPixel(disp, scr);

	hints.width = XDIM; hints.height = YDIM;
	hints.flags = USSize;
	wind = XCreateSimpleWindow(disp, DefaultRootWindow(disp),
				   0, 0, XDIM, YDIM, 0, bg, bg);
	XSetStandardProperties(disp, wind, wname, wname, None, av, ac, &hints);
	whints.flags = InputHint;
	whints.input = 1;
	XSetWMHints(disp, wind, &whints);

	gcv.foreground = bg;
	gcc = XCreateGC(disp, wind, GCForeground, &gcv);

	pix = XCreatePixmap(disp, wind, XDIM, YDIM,
			    DefaultDepth(disp, scr));
	XFillRectangle(disp, pix, gcc, 0, 0, XDIM, YDIM);

	gcv.foreground = fg;
	gcv.line_width = 2;
	gc = XCreateGC(disp, wind, GCForeground | GCLineWidth, &gcv);

	XDrawLines(disp, pix, gc, points, 4, CoordModeOrigin);

	XSelectInput(disp, wind, ExposureMask);
	XMapRaised(disp, wind);

	for (;;) {
		XNextEvent(disp, &xev);
		switch (xev.type) {
		case Expose:
			if (xev.xexpose.count == 0)
				XCopyArea(disp, pix, wind, gcc, 0, 0,
					  XDIM, YDIM, 0, 0);
			break;
		}
	}


	XFreeGC(disp, gc);
	XDestroyWindow(disp, wind);
	XCloseDisplay(disp);
	exit(0);
}