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

main(argc,argv)
int argc;
char **argv;
{
    Display *display;
    Window root, window;
    long fgcolor, bgcolor;
    int screen, pointx, pointy; 
    long eventmask = ButtonPressMask|ExposureMask|KeyPressMask;
    XEvent event;
    XGCValues gcval;
    GC draw;
    Colormap cmap;
    XColor color, ignore;
    char *colorname = "blue";
    XPoint          PolygonPoints[10];
    
    PolygonPoints[0].x=20; PolygonPoints[0].y=60;
    PolygonPoints[1].x=100; PolygonPoints[1].y=100;
    PolygonPoints[2].x=0; PolygonPoints[2].y=100;
    PolygonPoints[3].x=-100; PolygonPoints[3].y=0;
    PolygonPoints[4].x=0; PolygonPoints[4].y=-200;

    if (!(display = XOpenDisplay(argv[1]))) {
	perror("XOpenDisplay");
	exit(1);
    }

    root = RootWindow(display,screen = DefaultScreen(display));
    fgcolor = BlackPixel(display,screen);
    bgcolor = WhitePixel(display,screen);

    window = XCreateSimpleWindow(display,root, 0,0,400,400,2,fgcolor,bgcolor);

    cmap = DefaultColormap (display, screen);
    XAllocNamedColor(display, cmap, colorname, &color, &ignore);
    fgcolor = color.pixel;
    gcval.foreground = fgcolor;
    gcval.background = bgcolor;
    draw = XCreateGC(display,window,GCForeground|GCBackground,&gcval);

    XSelectInput(display,window,eventmask);
    XMapWindow(display,window);

    for (;;) {
	XWindowEvent(display,window,eventmask,&event);
	switch (event.type) {
	  case Expose:
	    XClearWindow(display,window);
	    break;
	  case ButtonPress:
/*
XDrawLines(display,window,draw,PolygonPoints,5, CoordModePrevious);
*/
XFillPolygon(display,window,draw,PolygonPoints,5,Complex, CoordModePrevious);
	    break;
          case KeyPress:
            exit(0);
	  default:
	    fprintf(stderr,"Unexpected event: %d\n",event.type);
	}
    }
}