Minimal xscreensaver

minimal.c

/* xscreensaver, Copyright (c) 1992-2008 Jamie Zawinski <jwz@jwz.org>
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation.  No representations are made about the suitability of this
 * software for any purpose.  It is provided "as is" without express or 
 * implied warranty.
 */

#include "screenhack.h"

struct state {
  Display *dpy;
  Window window;

  GC gc;
  int delay;
  unsigned long fg, bg, pixels [512];
  int npixels;
  int xlim, ylim;
  Colormap cmap;
};


static void *
minimal_init (Display *dpy, Window window)
{
  struct state *st = (struct state *) calloc (1, sizeof(*st));
  int i = 0;

  XGCValues gcv;
  XWindowAttributes xgwa;
  st->dpy = dpy;
  st->window = window;

  XGetWindowAttributes (st->dpy, st->window, &xgwa);
  st->xlim = xgwa.width;
  st->ylim = xgwa.height;
  st->cmap = xgwa.colormap;
  gcv.foreground= st->fg= get_pixel_resource(st->dpy, st->cmap, "foreground","Foreground");
  gcv.background= st->bg= get_pixel_resource(st->dpy, st->cmap, "background","Background");

  st->delay = get_integer_resource (st->dpy, "delay", "Integer");
  if (st->delay < 0) st->delay = 0;

  st->gc = XCreateGC (st->dpy, st->window, GCForeground, &gcv);

  for(st->npixels = 0; st->npixels < 512; st->npixels++)
  {
    XColor fgc;

    fgc.flags = DoRed|DoGreen|DoBlue;
    fgc.red = random ();
    fgc.green = random ();
    fgc.blue = random ();
    XAllocColor (st->dpy, st->cmap, &fgc);
    st->pixels[st->npixels] = fgc.pixel;
  }

  return st;
}

static unsigned long
minimal_draw (Display *dpy, Window window, void *closure)
{
  struct state *st = (struct state *) closure;
  int x, y, w=50, h=50, i;
  XGCValues gcv;

  x = random () % (st->xlim - w);
  y = random () % (st->ylim - h);

  gcv.foreground = st->pixels [random () % st->npixels];

  XChangeGC (st->dpy, st->gc, GCForeground, &gcv);
  XFillRectangle (st->dpy, st->window, st->gc, x, y, w, h);
  return st->delay;
}

static const char *minimal_defaults [] = {
  ".background: black",
  ".foreground: white",
  "*fpsSolid: true",
  "*delay:  10000",
  0
};

static XrmOptionDescRec minimal_options [] = {
  { "-delay",   ".delay", XrmoptionSepArg, 0 },
  { 0, 0, 0, 0 }
};

static void
minimal_reshape (Display *dpy, Window window, void *closure, 
                 unsigned int w, unsigned int h)
{
  struct state *st = (struct state *) closure;
  st->xlim = w;
  st->ylim = h;
}

static Bool
minimal_event (Display *dpy, Window window, void *closure, XEvent *event)
{
  return False;
}

static void
minimal_free (Display *dpy, Window window, void *closure)
{
}

XSCREENSAVER_MODULE ("Minimal", minimal)