/* 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.
*/
/* Algorithm from a Mac program by Chris Tate, written in 1988 or so. */
/* 18-Sep-97: Johannes Keukelaar (johannes@nada.kth.se): Improved screen
* eraser.
* 10-May-97: merged ellipse code by Dan Stromberg <strombrg@nis.acs.uci.edu>
* as found in xlockmore 4.03a10.
* 1992: jwz created.
*/
/* 25 April 2002: Matthew Strait <straitm@mathcs.carleton.edu> added
-subdelay option so the drawing process can be watched */
#include <math.h>
#include "screenhack.h"
#include "erase.h"
enum draw_state { HELIX, DRAW_HELIX, TRIG, DRAW_TRIG, LINGER, ERASE };
struct state {
enum draw_state dstate;
double sins [360];
double coss [360];
GC draw_gc;
unsigned int default_fg_pixel;
int sleep_time;
int subdelay;
eraser_state *eraser;
int width, height;
Colormap cmap;
int x1, y1, x2, y2, angle, i;
int radius1, radius2, d_angle, factor1, factor2, factor3, factor4;
int d_angle_offset;
int offset, dir, density;
};
static void *
helix_init (Display *dpy, Window window)
{
struct state *st = (struct state *) calloc (1, sizeof(*st));
int i;
XGCValues gcv;
XWindowAttributes xgwa;
st->sleep_time = get_integer_resource(dpy, "delay", "Integer");
st->subdelay = get_integer_resource(dpy, "subdelay", "Integer");
XGetWindowAttributes (dpy, window, &xgwa);
st->width = xgwa.width;
st->height = xgwa.height;
st->cmap = xgwa.colormap;
gcv.foreground = st->default_fg_pixel =
get_pixel_resource (dpy, st->cmap, "foreground", "Foreground");
st->draw_gc = XCreateGC (dpy, window, GCForeground, &gcv);
gcv.foreground = get_pixel_resource (dpy, st->cmap, "background", "Background");
for (i = 0; i < 360; i++)
{
st->sins [i] = sin ((((double) i) / 180.0) * M_PI);
st->coss [i] = cos ((((double) i) / 180.0) * M_PI);
}
st->dstate = (random() & 1) ? HELIX : TRIG;
return st;
}
static int
gcd (int a, int b)
{
while (b > 0)
{
int tmp;
tmp = a % b;
a = b;
b = tmp;
}
return (a < 0 ? -a : a);
}
static void
helix (Display *dpy, Window window, struct state *st)
{
int xmid = st->width / 2;
int ymid = st->height / 2;
int limit = 1 + (360 / gcd (360, st->d_angle));
if (st->i == 0)
{
st->x1 = xmid;
st->y1 = ymid + st->radius2;
st->x2 = xmid;
st->y2 = ymid + st->radius1;
st->angle = 0;
}
/* for (st->i = 0; st->i < limit; st->i++)*/
{
int tmp;
#define pmod(x,y) (tmp=((x) % (y)), (tmp >= 0 ? tmp : (tmp + (y))))
st->x1 = xmid + (((double) st->radius1) * st->sins [pmod ((st->angle * st->factor1), 360)]);
st->y1 = ymid + (((double) st->radius2) * st->coss [pmod ((st->angle * st->factor2), 360)]);
XDrawLine (dpy, window, st->draw_gc, st->x1, st->y1, st->x2, st->y2);
st->x2 = xmid + (((double) st->radius2) * st->sins [pmod ((st->angle * st->factor3), 360)]);
st->y2 = ymid + (((double) st->radius1) * st->coss [pmod ((st->angle * st->factor4), 360)]);
XDrawLine (dpy, window, st->draw_gc, st->x1, st->y1, st->x2, st->y2);
st->angle += st->d_angle;
}
st->i++;
if (st->i >= limit)
st->dstate = LINGER;
}
static void
trig (Display *dpy, Window window, struct state *st)
{
int xmid = st->width / 2;
int ymid = st->height / 2;
/* while (st->d_angle >= -360 && st->d_angle <= 360)*/
{
int tmp;
int angle = st->d_angle + st->d_angle_offset;
st->x1 = (st->sins [pmod(angle * st->factor1, 360)] * xmid) + xmid;
st->y1 = (st->coss [pmod(angle * st->factor1, 360)] * ymid) + ymid;
st->x2 = (st->sins [pmod(angle * st->factor2 + st->offset, 360)] * xmid) + xmid;
st->y2 = (st->coss [pmod(angle * st->factor2 + st->offset, 360)] * ymid) + ymid;
XDrawLine(dpy, window, st->draw_gc, st->x1, st->y1, st->x2, st->y2);
tmp = (int) 360 / (2 * st->density * st->factor1 * st->factor2);
if (tmp == 0) /* Do not want it getting stuck... */
tmp = 1; /* Would not need if floating point */
st->d_angle += st->dir * tmp;
}
if (st->d_angle < -360 || st->d_angle > 360)
st->dstate = LINGER;
}
#define min(a,b) ((a)<(b)?(a):(b))
static void
random_helix (Display *dpy, Window window, struct state *st,
XColor *color, Bool *got_color)
{
int radius;
double divisor;
radius = min (st->width, st->height) / 2;
st->i = 0;
st->d_angle = 0;
st->factor1 = 2;
st->factor2 = 2;
st->factor3 = 2;
st->factor4 = 2;
divisor = ((frand (3.0) + 1) * (((random() & 1) * 2) - 1));
if ((random () & 1) == 0)
{
st->radius1 = radius;
st->radius2 = radius / divisor;
}
else
{
st->radius2 = radius;
st->radius1 = radius / divisor;
}
while (gcd (360, st->d_angle) >= 2)
st->d_angle = random () % 360;
#define random_factor() \
(((random() % 7) ? ((random() & 1) + 1) : 3) \
* (((random() & 1) * 2) - 1))
while (gcd (gcd (gcd (st->factor1, st->factor2), st->factor3), st->factor4) != 1)
{
st->factor1 = random_factor ();
st->factor2 = random_factor ();
st->factor3 = random_factor ();
st->factor4 = random_factor ();
}
if (mono_p)
XSetForeground (dpy, st->draw_gc, st->default_fg_pixel);
else
{
hsv_to_rgb (random () % 360, frand (1.0), frand (0.5) + 0.5,
&color->red, &color->green, &color->blue);
if ((*got_color = XAllocColor (dpy, st->cmap, color)))
XSetForeground (dpy, st->draw_gc, color->pixel);
else
XSetForeground (dpy, st->draw_gc, st->default_fg_pixel);
}
XClearWindow (dpy, window);
}
static void
random_trig (Display *dpy, Window window, struct state *st,
XColor *color, Bool *got_color)
{
st->d_angle = 0;
st->factor1 = (random() % 8) + 1;
do {
st->factor2 = (random() % 8) + 1;
} while (st->factor1 == st->factor2);
st->dir = (random() & 1) ? 1 : -1;
st->d_angle_offset = random() % 360;
st->offset = ((random() % ((360 / 4) - 1)) + 1) / 4;
st->density = 1 << ((random() % 4) + 4); /* Higher density, higher angles */
if (mono_p)
XSetForeground (dpy, st->draw_gc, st->default_fg_pixel);
else
{
hsv_to_rgb (random () % 360, frand (1.0), frand (0.5) + 0.5,
&color->red, &color->green, &color->blue);
if ((*got_color = XAllocColor (dpy, st->cmap, color)))
XSetForeground (dpy, st->draw_gc, color->pixel);
else
XSetForeground (dpy, st->draw_gc, st->default_fg_pixel);
}
XClearWindow (dpy, window);
}
/* random_helix_or_trig */
static unsigned long
helix_draw (Display *dpy, Window window, void *closure)
{
struct state *st = (struct state *) closure;
Bool free_color = False;
XColor color;
int delay = st->subdelay;
int erase_delay = 10000;
int ii;
if (st->eraser) {
st->eraser = erase_window (dpy, window, st->eraser);
if (st->eraser)
delay = erase_delay;
goto END;
}
switch (st->dstate)
{
case LINGER:
delay = st->sleep_time * 1000000;
st->dstate = ERASE;
break;
case ERASE:
st->eraser = erase_window (dpy, window, st->eraser);
delay = erase_delay;
if (free_color) XFreeColors (dpy, st->cmap, &color.pixel, 1, 0);
st->dstate = (random() & 1) ? HELIX : TRIG;
break;
case DRAW_HELIX:
for (ii = 0; ii < 10; ii++) {
helix (dpy, window, st);
if (st->dstate != DRAW_HELIX)
break;
}
break;
case DRAW_TRIG:
for (ii = 0; ii < 5; ii++) {
trig (dpy, window, st);
if (st->dstate != DRAW_TRIG)
break;
}
break;
case HELIX:
random_helix (dpy, window, st, &color, &free_color);
st->dstate = DRAW_HELIX;
break;
case TRIG:
random_trig(dpy, window, st, &color, &free_color);
st->dstate = DRAW_TRIG;
break;
default:
abort();
}
END:
return delay;
}
static void
helix_reshape (Display *dpy, Window window, void *closure,
unsigned int w, unsigned int h)
{
struct state *st = (struct state *) closure;
st->width = w;
st->height = h;
}
static Bool
helix_event (Display *dpy, Window window, void *closure, XEvent *event)
{
return False;
}
static void
helix_free (Display *dpy, Window window, void *closure)
{
struct state *st = (struct state *) closure;
XFreeGC (dpy, st->draw_gc);
free (st);
}
static const char *helix_defaults [] = {
".background: black",
".foreground: white",
"*fpsSolid: true",
"*delay: 5",
"*subdelay: 20000",
#ifdef HAVE_MOBILE
"*ignoreRotation: True",
#endif
0
};
static XrmOptionDescRec helix_options [] = {
{ "-delay", ".delay", XrmoptionSepArg, 0 },
{ "-subdelay", ".subdelay", XrmoptionSepArg, 0 },
{ 0, 0, 0, 0 },
};
XSCREENSAVER_MODULE ("Helix", helix)
