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xenocara/app/xlockmore/modes/mandelbrot.c
matthieu 110b2a9207 Importing xlockmore 5.22
2006-11-26 11:07:42 +00:00

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/* -*- Mode: C; tab-width: 4; c-basic-offset: 4 -*- */
/* mandelbrot --- animated mandelbrot sets */
#if !defined( lint ) && !defined( SABER )
static const char sccsid[] = "@(#)mandelbrot.c 5.09 2003/06/30 xlockmore";
#endif
#define USE_LOG
/*-
* Copyright (c) 1997 Dan Stromberg <strombrg@nis.acs.uci.edu>
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose and without fee is hereby granted,
* provided that the above copyright notice appear in all copies and that
* both that copyright notice and this permission notice appear in
* supporting documentation.
*
* This file is provided AS IS with no warranties of any kind. The author
* shall have no liability with respect to the infringement of copyrights,
* trade secrets or any patents by this file or any part thereof. In no
* event will the author be liable for any lost revenue or profits or
* other special, indirect and consequential damages.
*
* See A.K. Dewdney's "Computer Recreations", Scientific American
* Magazine" Aug 1985 for more info. Also A.K. Dewdney's "Computer
* Recreations", Scientific American Magazine" Jul 1989, has some neat
* extensions besides z^n + c (n small but >= 2) some of these are:
* z^z + z^n + c <-- pow
* sin(z) + z^n + c <-- sin
* sin(z) + e^z + c
* These were first explored by a colleague of Mandelbrot, Clifford A.
* Pickover. These would make nice additions to add.
*
* Revision History:
* 03-Jul-2003: Added pow and sin options
* 30-Jun-2003: Changed writeable mode to be more consistent with
* xscreensaver's starfish
* 01-Nov-2000: Allocation checks
* 24-Mar-1999: DEM and Binary decomp options added by Tim Auckland
* <tda10.geo@yahoo.com>. Ideas from Peitgen & Saupe's
* "The Science of Fractal Images"
* 17-Nov-1998: Many Changes by Stromberg, including selection of
* interesting subregions, more extreme color ranges,
* reduction of possible powers to smaller/more interesting
* range, elimination of some unused code, slower color cycling,
* longer period of color cycling after the drawing is complete.
* Hopefully the longer color cycling period will make the mode
* reasonable even after CPUs are so fast that the drawing
* interval goes by quickly
* 20-Oct-1997: Written by Dan Stromberg <strombrg@nis.acs.uci.edu>
*/
#ifdef STANDALONE
#define MODE_mandelbrot
#define PROGCLASS "Mandelbrot"
#define HACK_INIT init_mandelbrot
#define HACK_DRAW draw_mandelbrot
#define mandelbrot_opts xlockmore_opts
#define DEFAULTS "*delay: 25000 \n" \
"*count: -8 \n" \
"*cycles: 20000 \n" \
"*ncolors: 200 \n"
#define SMOOTH_COLORS
#define WRITABLE_COLORS
#include "xlockmore.h" /* from the xscreensaver distribution */
#else /* !STANDALONE */
#include "xlock.h" /* from the xlockmore distribution */
#include "color.h"
#endif /* !STANDALONE */
#ifdef MODE_mandelbrot
#define MINPOWER 2
#define DEF_INCREMENT "1.00"
#define DEF_BINARY "False"
#define DEF_DEM "False"
#define DEF_LYAP "False"
#define DEF_ALPHA "False"
#define DEF_INDEX "False"
#define DEF_POW "False"
#define DEF_SIN "False"
#define DEF_CYCLE "True"
/* 4.0 is best for seeing if a point is inside the set, 13 is better if
** you want to get a pretty corona
*/
#define ESCAPE 13.0
#define FLOATRAND(min,max) ((min)+((double) LRAND()/((double) MAXRAND))*((max)-(min)))
typedef enum {
NONE,
LYAPUNOV,
ALPHA,
INDEX,
interior_size,
} interior_t;
/* incr also would be nice as a parameter. It controls how fast
the order is advanced. Non-integral values are not true orders,
but it's a somewhat interesting function anyway
*/
static float increment;
static Bool binary_p;
static Bool dem_p;
static Bool lyap_p;
static Bool alpha_p;
static Bool index_p;
static Bool pow_p;
static Bool sin_p;
static Bool cycle_p;
static XrmOptionDescRec opts[] =
{
{(char *) "-increment", (char *) ".mandelbrot.increment", XrmoptionSepArg, (caddr_t) NULL},
{(char *) "-binary", (char *) ".mandelbrot.binary", XrmoptionNoArg, (caddr_t) "on"},
{(char *) "+binary", (char *) ".mandelbrot.binary", XrmoptionNoArg, (caddr_t) "off"},
{(char *) "-dem", (char *) ".mandelbrot.dem", XrmoptionNoArg, (caddr_t) "on"},
{(char *) "+dem", (char *) ".mandelbrot.dem", XrmoptionNoArg, (caddr_t) "off"},
{(char *) "-lyap", (char *) ".mandelbrot.lyap", XrmoptionNoArg, (caddr_t) "on"},
{(char *) "+lyap", (char *) ".mandelbrot.lyap", XrmoptionNoArg, (caddr_t) "off"},
{(char *) "-alpha", (char *) ".mandelbrot.alpha", XrmoptionNoArg, (caddr_t) "on"},
{(char *) "+alpha", (char *) ".mandelbrot.alpha", XrmoptionNoArg, (caddr_t) "off"},
{(char *) "-index", (char *) ".mandelbrot.index", XrmoptionNoArg, (caddr_t) "on"},
{(char *) "+index", (char *) ".mandelbrot.index", XrmoptionNoArg, (caddr_t) "off"},
{(char *) "-pow", (char *) ".mandelbrot.pow", XrmoptionNoArg, (caddr_t) "on"},
{(char *) "+pow", (char *) ".mandelbrot.pow", XrmoptionNoArg, (caddr_t) "off"},
{(char *) "-sin", (char *) ".mandelbrot.sin", XrmoptionNoArg, (caddr_t) "on"},
{(char *) "+sin", (char *) ".mandelbrot.sin", XrmoptionNoArg, (caddr_t) "off"},
{(char *) "-cycle", (char *) ".mandelbrot.cycle", XrmoptionNoArg, (caddr_t) "on"},
{(char *) "+cycle", (char *) ".mandelbrot.cycle", XrmoptionNoArg, (caddr_t) "off"}
};
static argtype vars[] =
{
{(void *) & increment, (char *) "increment", (char *) "Increment", (char *) DEF_INCREMENT, t_Float},
{(void *) & binary_p, (char *) "binary", (char *) "Binary", (char *) DEF_BINARY, t_Bool},
{(void *) & dem_p, (char *) "dem", (char *) "Dem", (char *) DEF_DEM, t_Bool},
{(void *) & lyap_p, (char *) "lyap", (char *) "Lyap", (char *) DEF_LYAP, t_Bool},
{(void *) & alpha_p, (char *) "alpha", (char *) "Alpha", (char *) DEF_ALPHA, t_Bool},
{(void *) & index_p, (char *) "index", (char *) "Index", (char *) DEF_INDEX, t_Bool},
{(void *) & pow_p, (char *) "pow", (char *) "Pow", (char *) DEF_POW, t_Bool},
{(void *) & sin_p, (char *) "sin", (char *) "Sin", (char *) DEF_SIN, t_Bool},
{(void *) & cycle_p, (char *) "cycle", (char *) "Cycle", (char *) DEF_CYCLE, t_Bool}
};
static OptionStruct desc[] =
{
{(char *) "-increment value", (char *) "increasing orders"},
{(char *) "-/+binary", (char *) "turn on/off Binary Decomposition colour modulation"},
{(char *) "-/+dem", (char *) "turn on/off Distance Estimator Method (instead of escape time)"},
{(char *) "-/+lyap", (char *) "render interior with Lyapunov measure"},
{(char *) "-/+alpha", (char *) "render interior with Alpha level sets"},
{(char *) "-/+index", (char *) "render interior with Alpha indexes"},
{(char *) "-/+pow", (char *) "turn on/off adding z^z"},
{(char *) "-/+sin", (char *) "turn on/off adding sin(z)"},
{(char *) "-/+cycle", (char *) "turn on/off colour cycling"}
};
ModeSpecOpt mandelbrot_opts =
{sizeof opts / sizeof opts[0], opts, sizeof vars / sizeof vars[0], vars, desc};
#ifdef USE_MODULES
ModStruct mandelbrot_description =
{"mandelbrot", "init_mandelbrot", "draw_mandelbrot", "release_mandelbrot",
(char *) NULL, "init_mandelbrot", (char *) NULL, &mandelbrot_opts,
25000, -8, 20000, 1, 64, 1.0, "",
"Shows mandelbrot sets", 0, NULL};
#endif
#define ROUND_FLOAT(x,a) ((float) ((int) ((x) / (a) + 0.5)) * (a))
typedef struct {
double real, imag;
} complex;
static void
add(complex * a, complex b)
{
a->real = a->real + b.real;
a->imag = a->imag + b.imag;
}
static void
mult(complex * a, complex b)
{
double tr, ti;
/* a.real*b.real + i*a.real*b.imag + i*a.imag*b.real + i^2*a.imag*b.imag */
tr = a->real * b.real - a->imag * b.imag;
ti = a->real * b.imag + a->imag * b.real;
a->real = tr;
a->imag = ti;
}
static void
cln(complex * a)
{
/* ln(z) = ln ((x^2 + y^2)^(1/2)) + i * invtan(y/x) */
double tr, ti;
tr = sqrt(a->real * a->real + a->imag * a->imag);
ti = (a->real == 0.0 && a->imag == 0.0) ? 0.0 :
atan2(a->imag, a->real);
a->real = tr;
a->imag = ti;
}
static void
complex_exp(complex * a)
{
/* e^z = e^x * (cos(y) + i * sin(y)) */
double tr;
tr = exp(a->real);
a->real = tr * cos(a->imag);
a->imag = tr * sin(a->imag);
}
static complex
complex_pow(complex a, complex b)
{
/* a^z = e^(z * ln(a)) */
complex c, d;
c = a;
d = b;
cln(&c);
mult(&d, c);
complex_exp(&d);
return d;
}
static complex
complex_sin(complex a)
{
/* sin(z) = -i * (e^(i * z) - e^(-i * z)) / 2 */
/* cos(z) = (e^(i * z) - e^(-i * z)) / 2 */
complex c, d, i;
c = a;
d = a;
i.real = 0; i.imag = 1;
/* inefficient but I just want to see the picture */
mult(&c, i);
i.imag = -i.imag;
mult(&d, i);
complex_exp(&c);
complex_exp(&d);
d.real = -d.real;
d.imag = -d.imag;
add(&c, d);
c.real = c.real / 2;
c.imag = c.imag / 2;
mult(&c, i);
return c;
}
/* this is a true power function. */
static void
ipow(complex * a, int n)
{
switch (n) {
case 1:
return;
case 2:
mult(a, *a);
return;
default:
{
complex a2;
int t2;
a2 = *a; /* Not very efficient to use: mult(a, ipow(&a2, n-1)); */
t2 = n / 2;
ipow(&a2, t2);
mult(&a2, a2);
if (t2 * 2 != n) /* if n is odd */
mult(&a2, *a);
*a = a2;
}
}
}
typedef struct {
int counter;
double power;
int column;
Bool backwards;
int ncolors;
unsigned int cur_color;
GC gc;
Colormap cmap;
unsigned long blackpixel, whitepixel, fg, bg;
int direction;
XColor *colors;
complex extreme_ul;
complex extreme_lr;
complex ul;
complex lr;
int screen_width;
int screen_height;
int reptop;
Bool dem, pow, sin, cycle_p, mono_p, no_colors;
Bool binary;
interior_t interior;
ModeInfo *mi;
} mandelstruct;
static mandelstruct *mandels = (mandelstruct *) NULL;
/* do the iterations
* if binary is true, check halfplane of last iteration.
* if demrange is non zero, estimate lower bound of dist(c, M)
*
* DEM - Distance Estimator Method
* Based on Peitgen & Saupe's "The Science of Fractal Images"
*
* ALPHA - level sets of closest return.
* INDEX - index of ALPHA.
* Based on Peitgen & Richter's "The Beauty of Fractals" (Fig 33,34)
*
* LYAPUNOV - lyapunov exponent estimate
* Based on an idea by Jan Thor
*
*/
static int
reps(complex c, double p, int r, Bool binary, interior_t interior, double demrange, Bool zpow, Bool zsin)
{
int rep;
int escaped = 0;
complex t;
int escape = (int) ((demrange == 0) ? ESCAPE :
ESCAPE*ESCAPE*ESCAPE*ESCAPE); /* 2 more iterations */
complex t1;
complex dt;
double L = 0.0;
double l2;
double dl2 = 1.0;
double alpha2 = ESCAPE;
int index = 0;
#if defined(USE_LOG)
double log_top = log((double) r);
#endif
t = c;
dt.real = 1; dt.imag = 0;
for (rep = 0; rep < r; rep++) {
t1 = t;
ipow(&t, (int) p);
add(&t, c);
if (zpow)
add(&t, complex_pow(t1, t1));
if (zsin)
add(&t, complex_sin(t1));
l2 = t.real * t.real + t.imag * t.imag;
if (l2 <= alpha2) {
alpha2 = l2;
index = rep;
}
if (l2 >= escape) {
escaped = 1;
break;
} else if (interior == LYAPUNOV) {
/* Crude estimate of Lyapunov exponent. The stronger the
attractor, the more negative the exponent will be. */
/* n=N
L = lim 1/N * Sum log(abs(dx(n+1)/dx(n)))/ln(2)
N->inf n=1
*/
L += log(sqrt(l2));
}
if (demrange){
/* compute dt/dc
* p-1
* dt = p * t * dt + 1
* k+1 k k
*/
/* Note this is incorrect for zpow or zsin, but a correct
implementation is too slow to be useful. */
dt.real *= p; dt.imag *= p;
if(p > 2) ipow(&t1, (int) (p - 1));
mult(&dt, t1);
dt.real += 1;
dl2 = dt.real * dt.real + dt.imag * dt.imag;
if (dl2 >= 1e300) {
escaped = 2;
break;
}
}
}
if (escaped) {
if(demrange) {
double mt = sqrt(t1.real * t1.real + t1.imag * t1.imag);
/* distance estimate */
double dist = 0.5 * mt * log(mt) / sqrt(dl2);
/* scale for viewing. Allow black when showing interior. */
rep = (int) (((interior > NONE)?0:1) + 10*r*dist/demrange);
if(rep > r-1) rep = r-1; /* chop into color range */
}
if(binary && t.imag > 0)
rep = (r + rep / 2) % r; /* binary decomp */
#ifdef USE_LOG
if ( rep > 0 )
rep = (int) (r * log((double) rep)/log_top); /* Log Scale */
#endif
return rep;
} else if (interior == LYAPUNOV) {
return -(int)(L/M_LN2) % r;
} else if (interior == INDEX) {
return 1 + index;
} else if (interior == ALPHA) {
return (int) (r * sqrt(alpha2));
} else
return r;
}
static void
Select(/* input variables first */
complex *extreme_ul, complex *extreme_lr,
int width, int height, int power, int top,
Bool zpow, Bool zsin,
/* output variables follow */
complex *selected_ul,complex *selected_lr)
{
double precision;
double s2;
int inside;
int uninteresting;
int found;
int tries;
found = 0;
while (!found) {
/* select a precision - be careful with this */
precision = pow(2.0,FLOATRAND(-9.0,-18.0));
/* (void) printf("precision is %f\n",precision); */
for (tries=0;tries<10000&&!found;tries++) {
/* it eventually turned out that this inner loop doesn't always
** terminate - so we just try 10000 times, and if we don't get
** anything interesting, we pick a new precision
*/
complex temp;
int sample_step = 4;
int row,column;
inside = 0;
uninteresting = 0;
/* pick a random point in the allowable range */
temp.real = FLOATRAND(extreme_ul->real,extreme_lr->real);
temp.imag = FLOATRAND(extreme_ul->imag,extreme_lr->imag);
/* find upper left and lower right points */
selected_ul->real = temp.real - precision * width / 2;
selected_lr->real = temp.real + precision * width / 2;
selected_ul->imag = temp.imag - precision * height / 2;
selected_lr->imag = temp.imag + precision * height / 2;
/* sample the results we'd get from this choice, accept or reject
** accordingly
*/
for (row=0; row<sample_step; row++) {
for (column=0; column<sample_step; column++) {
int r;
temp.imag = selected_ul->imag +
(selected_ul->imag - selected_lr->imag) *
(((double)row)/sample_step);
temp.real = selected_ul->real +
(selected_ul->real - selected_lr->real) *
(((double)column)/sample_step);
r = reps(temp,(double) power,top,0,0,0.0, zpow, zsin);
/* Here, we just want to see if the point is in the set,
** not if we can make something pretty
*/
if (r == top) {
inside++;
}
if (r < 2) {
uninteresting++;
}
}
}
s2 = sample_step*sample_step;
/* more than 10 percent, but less than 60 percent inside the set */
if (inside >= ceil(s2/10.0) && inside <= s2*6.0/10.0 &&
uninteresting <= s2/10.0) {
/* this one looks interesting */
found = 1;
}
/* else
*** this does not look like a real good combination, so back
*** up to the top of the loop to try another possibility
*/
}
}
}
static void
free_mandelbrot(Display *display, mandelstruct *mp)
{
ModeInfo *mi = mp->mi;
if (MI_IS_INSTALL(mi) && MI_NPIXELS(mi) > 2) {
MI_WHITE_PIXEL(mi) = mp->whitepixel;
MI_BLACK_PIXEL(mi) = mp->blackpixel;
#ifndef STANDALONE
MI_FG_PIXEL(mi) = mp->fg;
MI_BG_PIXEL(mi) = mp->bg;
#endif
if (mp->colors != NULL) {
if (mp->ncolors && !mp->no_colors)
free_colors(display, mp->cmap, mp->colors,
mp->ncolors);
free(mp->colors);
mp->colors = (XColor *) NULL;
}
if (mp->cmap != None) {
XFreeColormap(display, mp->cmap);
mp->cmap = None;
}
}
if (mp->gc != None) {
XFreeGC(display, mp->gc);
mp->gc = None;
}
}
#ifndef STANDALONE
extern char *background;
extern char *foreground;
#endif
void
init_mandelbrot(ModeInfo * mi)
{
Display *display = MI_DISPLAY(mi);
Window window = MI_WINDOW(mi);
mandelstruct *mp;
if (mandels == NULL) {
if ((mandels = (mandelstruct *) calloc(MI_NUM_SCREENS(mi),
sizeof (mandelstruct))) == NULL)
return;
}
mp = &mandels[MI_SCREEN(mi)];
mp->mi = mi;
mp->screen_width = MI_WIDTH(mi);
mp->screen_height = MI_HEIGHT(mi);
mp->backwards = (Bool) (LRAND() & 1);
if (mp->backwards)
mp->column = mp->screen_width - 1;
else
mp->column = 0;
mp->power = NRAND(3) + MINPOWER;
mp->counter = 0;
MI_CLEARWINDOW(mi);
if (MI_IS_FULLRANDOM(mi)) {
mp->binary = (Bool) (LRAND() & 1);
mp->dem = (Bool) (LRAND() & 1);
mp->interior = NRAND(interior_size);
#if 0
/* too slow */
mp->pow = (NRAND(5) == 0);
mp->sin = (NRAND(5) == 0);
#endif
} else {
mp->binary = binary_p;
mp->dem = dem_p;
if (index_p) {
mp->interior = INDEX;
} else if(alpha_p) {
mp->interior = ALPHA;
} else if(lyap_p) {
mp->interior = LYAPUNOV;
} else {
mp->interior = NONE;
}
mp->pow = pow_p;
mp->sin = sin_p;
}
mp->reptop = 300;
/* these could be tuned a little closer, but the selection
** process throws out the chaf anyway, it just takes slightly
** longer
*/
mp->extreme_ul.real = -3.0;
mp->extreme_ul.imag = -3.0;
mp->extreme_lr.real = 3.0;
mp->extreme_lr.imag = 3.0;
if (!mp->gc) {
if (MI_IS_INSTALL(mi) && MI_NPIXELS(mi) > 2) {
XColor color;
#ifndef STANDALONE
mp->fg = MI_FG_PIXEL(mi);
mp->bg = MI_BG_PIXEL(mi);
#endif
mp->blackpixel = MI_BLACK_PIXEL(mi);
mp->whitepixel = MI_WHITE_PIXEL(mi);
if ((mp->cmap = XCreateColormap(display, window,
MI_VISUAL(mi), AllocNone)) == None) {
free_mandelbrot(display, mp);
return;
}
XSetWindowColormap(display, window, mp->cmap);
(void) XParseColor(display, mp->cmap, "black", &color);
(void) XAllocColor(display, mp->cmap, &color);
MI_BLACK_PIXEL(mi) = color.pixel;
(void) XParseColor(display, mp->cmap, "white", &color);
(void) XAllocColor(display, mp->cmap, &color);
MI_WHITE_PIXEL(mi) = color.pixel;
#ifndef STANDALONE
(void) XParseColor(display, mp->cmap, background, &color);
(void) XAllocColor(display, mp->cmap, &color);
MI_BG_PIXEL(mi) = color.pixel;
(void) XParseColor(display, mp->cmap, foreground, &color);
(void) XAllocColor(display, mp->cmap, &color);
MI_FG_PIXEL(mi) = color.pixel;
#endif
mp->colors = (XColor *) NULL;
mp->ncolors = 0;
}
if ((mp->gc = XCreateGC(display, MI_WINDOW(mi),
(unsigned long) 0, (XGCValues *) NULL)) == None) {
free_mandelbrot(display, mp);
return;
}
}
MI_CLEARWINDOW(mi);
/* Set up colour map */
mp->direction = (LRAND() & 1) ? 1 : -1;
if (MI_IS_INSTALL(mi) && MI_NPIXELS(mi) > 2) {
if (mp->colors != NULL) {
if (mp->ncolors && !mp->no_colors)
free_colors(display, mp->cmap, mp->colors, mp->ncolors);
free(mp->colors);
mp->colors = (XColor *) NULL;
}
mp->ncolors = MI_NCOLORS(mi);
if (mp->ncolors < 2)
mp->ncolors = 2;
if (mp->ncolors <= 2)
mp->mono_p = True;
else
mp->mono_p = False;
if (mp->mono_p)
mp->colors = (XColor *) NULL;
else
if ((mp->colors = (XColor *) malloc(sizeof (*mp->colors) *
(mp->ncolors + 1))) == NULL) {
free_mandelbrot(display, mp);
return;
}
mp->cycle_p = has_writable_cells(mi);
if (mp->cycle_p) {
if (MI_IS_FULLRANDOM(mi)) {
if (!NRAND(8))
mp->cycle_p = False;
else
mp->cycle_p = True;
} else {
mp->cycle_p = cycle_p;
}
}
if (!mp->mono_p) {
if (!(LRAND() % 10))
make_random_colormap(
#if STANDALONE
display, MI_WINDOW(mi),
#else
mi,
#endif
mp->cmap, mp->colors, &mp->ncolors,
True, True, &mp->cycle_p);
else if (!(LRAND() % 2))
make_uniform_colormap(
#if STANDALONE
display, MI_WINDOW(mi),
#else
mi,
#endif
mp->cmap, mp->colors, &mp->ncolors,
True, &mp->cycle_p);
else
make_smooth_colormap(
#if STANDALONE
display, MI_WINDOW(mi),
#else
mi,
#endif
mp->cmap, mp->colors, &mp->ncolors,
True, &mp->cycle_p);
}
XInstallColormap(display, mp->cmap);
if (mp->ncolors < 2) {
mp->ncolors = 2;
mp->no_colors = True;
} else
mp->no_colors = False;
if (mp->ncolors <= 2)
mp->mono_p = True;
if (mp->mono_p)
mp->cycle_p = False;
}
if (MI_IS_INSTALL(mi) && MI_NPIXELS(mi) > 2) {
if (mp->mono_p) {
mp->cur_color = MI_BLACK_PIXEL(mi);
}
}
Select(&mp->extreme_ul,&mp->extreme_lr,
mp->screen_width,mp->screen_height,
(int) mp->power,mp->reptop, mp->pow, mp->sin,
&mp->ul,&mp->lr);
}
void
draw_mandelbrot(ModeInfo * mi)
{
Display *display = MI_DISPLAY(mi);
Window window = MI_WINDOW(mi);
int h;
complex c;
double demrange;
mandelstruct *mp;
if (mandels == NULL)
return;
mp = &mandels[MI_SCREEN(mi)];
MI_IS_DRAWN(mi) = True;
if (MI_IS_INSTALL(mi) && MI_NPIXELS(mi) > 2) {
if (mp->mono_p) {
XSetForeground(display, mp->gc, mp->cur_color);
} else {
mp->cur_color = (mp->cur_color + 1) % mp->ncolors;
XSetForeground(display, mp->gc, mp->colors[mp->cur_color].pixel);
}
} else {
if (MI_NPIXELS(mi) > 2)
XSetForeground(display, mp->gc, MI_PIXEL(mi, mp->cur_color));
else if (mp->cur_color)
XSetForeground(display, mp->gc, MI_BLACK_PIXEL(mi));
else
XSetForeground(display, mp->gc, MI_WHITE_PIXEL(mi));
if (++mp->cur_color >= (unsigned int) MI_NPIXELS(mi))
mp->cur_color = 0;
}
/* Rotate colours */
if (mp->cycle_p) {
rotate_colors(display, mp->cmap, mp->colors, mp->ncolors,
mp->direction);
if (!(LRAND() % 1000))
mp->direction = -mp->direction;
}
/* so we iterate columns beyond the width of the physical screen, so that
** we just wait around and show what we've done
*/
if ((!mp->backwards && (mp->column >= 3 * mp->screen_width)) ||
(mp->backwards && (mp->column < -2 * mp->screen_width))) {
/* reset to left edge of screen, bump power */
mp->backwards = (Bool) (LRAND() & 1);
if (mp->backwards)
mp->column = mp->screen_width - 1;
else
mp->column = 0;
mp->power = NRAND(3) + MINPOWER;
/* select a new region! */
Select(&mp->extreme_ul,&mp->extreme_lr,
mp->screen_width,mp->screen_height,
(int) mp->power,mp->reptop, mp->pow, mp->sin,
&mp->ul,&mp->lr);
} else if (mp->column >= mp->screen_width || mp->column < 0) {
/* delay a while */
if (mp->backwards)
mp->column--;
else
mp->column++;
mp->counter++;
return;
}
/* demrange is used to give some idea of scale */
demrange = mp->dem ? fabs(mp->ul.real - mp->lr.real) / 2 : 0;
for (h = 0; h < mp->screen_height; h++) {
unsigned int color;
int result;
/* c.real = 1.3 - (double) mp->column / mp->screen_width * 3.4; */
/* c.imag = -1.6 + (double) h / mp->screen_height * 3.2; */
c.real = mp->ul.real +
(mp->ul.real-mp->lr.real)*(((double)(mp->column))/mp->screen_width);
c.imag = mp->ul.imag +
(mp->ul.imag - mp->lr.imag)*(((double) h) / mp->screen_height);
result = reps(c, mp->power, mp->reptop, mp->binary, mp->interior, demrange, mp->pow, mp->sin);
if (result < 0 || result >= mp->reptop)
XSetForeground(display, mp->gc, MI_BLACK_PIXEL(mi));
else {
color=(unsigned int) ((MI_NPIXELS(mi) * (float)result) / mp->reptop);
XSetForeground(display, mp->gc, MI_PIXEL(mi, color));
}
/* we no longer have vertical symmetry - so we compute all points
** and don't draw with redundancy
*/
XDrawPoint(display, window, mp->gc, mp->column, h);
}
if (mp->backwards)
mp->column--;
else
mp->column++;
mp->counter++;
if (mp->counter > MI_CYCLES(mi)) {
init_mandelbrot(mi);
}
}
void
release_mandelbrot(ModeInfo * mi)
{
if (mandels != NULL) {
int screen;
for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++)
free_mandelbrot(MI_DISPLAY(mi), &mandels[screen]);
free(mandels);
mandels = (mandelstruct *) NULL;
}
}
#endif /* MODE_mandelbrot */
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