/*
 * Copyright status: This file is in the public domain.  In
 *  jurisdictions where a copyright holder cannot explicitly release IP
 *  into the public domain, this should be interpreted as the closest
 *  available approximation, probably something like "you are granted a
 *  license to use this file in any way you see fit".
 *
 * This is a tiny test program to test for a common X server bug.
 *
 * The bug is that creating a pixmap cursor with a mask of None (which
 *  is defined to display all pixels of the source) effectively extends
 *  the source pixmap to the right with server-dependent data,
 *  typically background pixels, to a width such as 16 or 32 pixels.
 *  While this is not, strictly, contrary to the spec (cursor
 *  components "may be transformed arbitrarily to meet display
 *  limitations"), the same server typically does the right thing when
 *  an explicit mask bitmap full of 1s is supplied as the mask,
 *  demonstrating that there is no actual need to mangle the pixmap,
 *  which is why I call this a bug.
 *
 * Compile this with whatever options are needed to find your X include
 *  files and libraries, typically something like
 *
 *	cc -o cursor-bug cursor-bug.c -lX11
 *
 *  (depending on your system, you may need a -I option as well).  When
 *  you run it you should get a 600x200 window.  The middle third
 *  should be black; the left and right thirds should be a checkerboard
 *  grey (alternate pixels white and black - whether this looks like a
 *  checkerboard or a uniform grey or what depends on your display and
 *  in some cases your eyes).  Each of the grey areas uses a 3x16
 *  cursor which is a 1x14 white vertical line with a black surround.
 *  The left third uses an explicit pixmap full of 1s as the mask when
 *  creating its cursor; the right third uses None for its.  If the
 *  cursor looks the same over the left and right thirds, great; the
 *  bug isn't present in your server, or at least isn't manifesting for
 *  you.  If the left one looks fine but the right one is extended to
 *  the right, typically with black, you've got the bug.
 */

#include <stdio.h>
#include <stdlib.h>

#include <X11/Xlib.h>

extern const char *__progname;

static Display *disp;
static Screen *scr;
static int depth;
static Window rootwin;
static GC wingc;
static GC bitgc;
static Colormap cmap;
static Pixmap bgpm;
static Window win;
static Window goodwin;
static Window badwin;
static XColor cbg;
static XColor cfg;
static Pixmap cdata;
static Pixmap cmask;
static Cursor goodcurs;
static Cursor badcurs;

static void setup_colour(XColor *c, unsigned short int r, unsigned short int g, unsigned short int b)
{
 c->red = r;
 c->green = g;
 c->blue = b;
 c->flags = DoRed | DoGreen | DoBlue;
 if (! XAllocColor(disp,cmap,c))
  { fprintf(stderr,"%s: can't XAllocColor #%04hx%04hx%04hx\n",__progname,r,g,b);
    exit(1);
  }
}

int main(void);
int main(void)
{
 XSetWindowAttributes attr;

 disp = XOpenDisplay(0);
 scr = XDefaultScreenOfDisplay(disp);
 depth = XDefaultDepthOfScreen(scr);
 rootwin = XRootWindowOfScreen(scr);
 wingc = XDefaultGCOfScreen(scr);
 cmap = XDefaultColormapOfScreen(scr);
 setup_colour(&cbg,0,0,0);
 setup_colour(&cfg,65535,65535,65535);
 bgpm = XCreatePixmap(disp,rootwin,2,2,depth);
 XSetForeground(disp,wingc,cbg.pixel);
 XDrawPoint(disp,bgpm,wingc,0,0);
 XDrawPoint(disp,bgpm,wingc,1,1);
 XSetForeground(disp,wingc,cfg.pixel);
 XDrawPoint(disp,bgpm,wingc,0,1);
 XDrawPoint(disp,bgpm,wingc,1,0);
 cdata = XCreatePixmap(disp,rootwin,3,16,1);
 cmask = XCreatePixmap(disp,rootwin,3,16,1);
 bitgc = XCreateGC(disp,cdata,0,0);
 XSetForeground(disp,bitgc,0);
 XFillRectangle(disp,cdata,bitgc,0,0,3,16);
 XSetForeground(disp,bitgc,1);
 XFillRectangle(disp,cdata,bitgc,1,1,1,14);
 XFillRectangle(disp,cmask,bitgc,0,0,3,16);
 goodcurs = XCreatePixmapCursor(disp,cdata,cmask,&cfg,&cbg,1,8);
 badcurs = XCreatePixmapCursor(disp,cdata,None,&cfg,&cbg,1,8);
 attr.background_pixel = cbg.pixel;
 attr.colormap = cmap;
 win = XCreateWindow(disp,rootwin,0,0,600,200,0,depth,InputOutput,
	CopyFromParent,CWBackPixel|CWColormap,&attr);
 attr.background_pixmap = bgpm;
 attr.cursor = goodcurs;
 goodwin = XCreateWindow(disp,win,0,0,200,200,0,depth,InputOutput,
	CopyFromParent,CWBackPixmap|CWCursor,&attr);
 attr.background_pixmap = bgpm;
 attr.cursor = badcurs;
 badwin = XCreateWindow(disp,win,400,0,200,200,0,depth,InputOutput,
	CopyFromParent,CWBackPixmap|CWCursor,&attr);
 XMapSubwindows(disp,win);
 XMapRaised(disp,win);
 while (1)
  { XEvent e;
    XNextEvent(disp,&e);
  }
}