/*
   Press LMB to draw a rect with solid line: 		visible
   Press RMB to draw a rect with dash line: 		invisible
 */

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

#define WINW	1000
#define WINH	800

int main(int argc, char **argv)
{
    Display        *dpy;
    Window          win;
    XSetWindowAttributes attr;
    XEvent event;
    int	depth, screen;
    Visual *visual;

    XSizeHints hints;
    XWMHints wmhints;

    dpy = XOpenDisplay(0);
    screen = DefaultScreen(dpy);
    depth = DefaultDepth(dpy, screen);
    visual=DefaultVisual(dpy, screen);

    attr.background_pixel = 0;
    attr.backing_store = WhenMapped;
    win = XCreateWindow(dpy, DefaultRootWindow(dpy),
                        0, 0, WINW, WINH, 0, depth, 
	       	        InputOutput, visual,
                        CWBackPixel|CWBackingStore, &attr);

    hints.flags=PPosition;
    hints.x=100;
    hints.y=100;
    XSetNormalHints(dpy, win, &hints);

    wmhints.flags=StateHint|InputHint;
    wmhints.initial_state=NormalState;
    wmhints.input=True;
    XSetWMHints(dpy, win, &wmhints);
    XSelectInput(dpy, win, ButtonPressMask|PropertyChangeMask);
    XSelectInput(dpy, DefaultRootWindow(dpy), PropertyChangeMask);

    XMapRaised(dpy, win);
    XSync(dpy, False);

    XGCValues gcv;
    gcv.line_width=1;
    gcv.foreground=0xffffffff;
    gcv.dashes = 10;
    GC gc = XCreateGC(dpy, win, GCLineWidth | GCForeground | GCDashList, &gcv);
    XFlush(dpy);

    while (1)
    {
	short x1 = 330, y1 = -15000;
#ifndef BREAK
	short x2 = 530, y2 = 31340;
#else
	short x2 = 530, y2 = 31341;
#endif
    	XNextEvent(dpy, &event);

	if (event.type==ButtonPress)
	{
	     XClearWindow(dpy, win);

	     if (event.xbutton.button==1) /* LMB */
	     {
    		gcv.line_style = LineSolid;
	     }
	     else
	     {
    		gcv.line_style = LineOnOffDash;
	     }

	     XChangeGC(dpy, gc, GCLineStyle, &gcv);
	     XDrawLine(dpy, win, gc, x1, y1, x2, y2);
	     XFlush(dpy);
	}
    }

    return 0;
}