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CC0 1.0 Universal
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# fractal
# Written in 2020 by Lucas
# CC0 1.0 Universal/Public domain - No rights reserved
#
# To the extent possible under law, the author(s) have dedicated all
# copyright and related and neighboring rights to this software to the
# public domain worldwide. This software is distributed without any
# warranty. You should have received a copy of the CC0 Public Domain
# Dedication along with this software. If not, see
# <http://creativecommons.org/publicdomain/zero/1.0/>.
.POSIX:
.SUFFIXES:
.SUFFIXES: .c .o
.c.o:
${CC} ${FRACTAL_CFLAGS} -c $<
FRACTAL_CFLAGS = -O3 -ffast-math -march=native -mtune=native \
${CFLAGS}
BIN = fractal fun-gen
FRACTAL_OBJ = criticals.o fractal.o julia.o palette.o pnmout.o util.o
FUN_GEN_OBJ = fun-gen.o
OBJ = ${FRACTAL_OBJ} ${FUN_GEN_OBJ}
all: fractal
julia.o: fun.h
fractal: ${FRACTAL_OBJ}
${CC} ${LDFLAGS} -o $@ ${FRACTAL_OBJ} -lm
fun-gen: ${FUN_GEN_OBJ}
${CC} ${LDFLAGS} -o $@ ${FUN_GEN_OBJ} -lm
clean:
rm -f ${OBJ} ${BIN} fun.h

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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include "criticals.h"
#include "util.h"
size_t newton_iters = 100;
static size_t idx = 0;
static long double complex criticals[100];
int
behaves_critical(long double complex (*df)(long double complex),
long double complex (*ddf)(long double complex), long double complex z,
long double complex *crit, long double bailout, long double epsilon)
{
size_t i;
for (i = 0; i < newton_iters && cabsl(z) < bailout; i++)
z = z - df(z) / ddf(z);
if (cabsl(df(z)) < epsilon) {
*crit = z;
return 1;
}
return 0;
}
void
add_critical_point(long double complex z)
{
size_t i;
if (idx >= nelems(criticals))
return;
for (i = 0; i < idx; i++)
if (cabsl(z - criticals[i]) < 1.0e-9)
return;
criticals[idx++] = z;
}
size_t
ncriticals(void)
{
return idx;
}
long double complex
get_critical(size_t i)
{
if (i >= idx) {
fprintf(stderr, "get_critical: index %zu out of range", i);
exit(1);
}
return criticals[i];
}

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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <complex.h>
#include <stddef.h>
int behaves_critical(long double complex (*)(long double complex),
long double complex (*)(long double complex), long double complex,
long double complex *, long double, long double);
void add_critical_point(long double complex);
size_t ncriticals(void);
long double complex get_critical(size_t);

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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "util.h"
int palette_main(int, char *[]);
int julia_main(int, char *[]);
static void
usage(void)
{
fprintf(stderr, "Usage: %s [-s seed] <prog> [prog_args]\n",
xgetprogname());
exit(1);
}
int
main(int argc, char *argv[])
{
char *end;
intmax_t v;
long seed;
int ch;
seed = time(NULL);
while ((ch = getopt(argc, argv, "s:")) != -1)
switch (ch) {
case 's':
errno = 0;
v = strtoimax(optarg, &end, 0);
if (*end != '\0' || errno != 0 || v > LONG_MAX ||
v < LONG_MIN) {
fprintf(stderr, "-s: Invalid value \"%s\".",
optarg);
exit(1);
}
seed = (long)v;
break;
default:
usage();
}
argc -= optind;
argv += optind;
optind = 1;
if (argc == 0)
usage();
fprintf(stderr, "seed=%ld\n", seed);
xsrand48(seed);
if (strcmp(argv[0], "palette") == 0)
return palette_main(argc, argv);
else if (strcmp(argv[0], "julia") == 0)
return julia_main(argc, argv);
else
usage();
return 1; /* UNREACHABLE */
}

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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
static char *argv0;
struct poly {
unsigned int degree;
double *coefs;
const char *expr;
};
static void
poly_init(struct poly *p, unsigned int degree, const char *expr)
{
if ((p->coefs = malloc((degree + 1) * sizeof(double))) == NULL) {
fprintf(stderr, "out of memory\n");
exit(1);
}
p->degree = degree;
p->expr = expr;
}
static void
poly_derivate(struct poly p, struct poly *dp, const char *expr)
{
unsigned int i;
poly_init(dp, p.degree == 0 ? 0 : p.degree - 1, expr);
for (i = p.degree; i > 0; i--)
dp->coefs[i - 1] = p.coefs[i] * i;
}
static int
poly_cmp(const void *vp, const void *vq)
{
const struct poly *p = vp, *q = vq;
return p->degree - q->degree;
}
static void
poly_free(struct poly *p)
{
free(p->coefs);
}
static void
print_fun_header(const char *fun_name)
{
printf("static long double complex\n");
printf("%s(long double complex z)\n", fun_name);
printf("{\n");
}
static void
print_fun_body(size_t n, struct poly *polys)
{
size_t i, j;
unsigned int d;
printf("\tlong double complex a");
for (i = 0; i < n; i++)
printf(", %s = 0.0L", polys[i].expr);
printf(";\n\n");
d = 0;
for (i = 0; i < n; i++) {
for (; d <= polys[i].degree; d++) {
if (d == 0)
printf("\ta = 1.0L;\n");
else
printf("\ta *= z;\n");
for (j = n; j > i; j--)
if (polys[j - 1].coefs[d] != 0.0L)
printf("\t%s += %.20f * a;\n",
polys[j - 1].expr,
polys[j - 1].coefs[d]);
printf("\n");
}
}
}
static void
print_fun_footer(void)
{
printf("}\n");
}
static void
print_funs(struct poly p, struct poly q)
{
struct poly polys[6];
struct poly dp, ddp, dq, ddq;
polys[0] = p;
polys[1] = q;
qsort(polys, 2, sizeof(struct poly), &poly_cmp);
print_fun_header("f");
print_fun_body(2, polys);
printf("\treturn p / q;\n");
print_fun_footer();
poly_derivate(p, &dp, "dp");
poly_derivate(q, &dq, "dq");
polys[0] = p;
polys[1] = q;
polys[2] = dp;
polys[3] = dq;
qsort(polys, 4, sizeof(struct poly), &poly_cmp);
printf("\n");
print_fun_header("df");
print_fun_body(4, polys);
printf("\treturn (dp * q - p * dq) / (q * q);\n");
print_fun_footer();
poly_derivate(dp, &ddp, "ddp");
poly_derivate(dq, &ddq, "ddq");
polys[0] = p;
polys[1] = q;
polys[2] = dp;
polys[3] = dq;
polys[4] = ddp;
polys[5] = ddq;
qsort(polys, 6, sizeof(struct poly), &poly_cmp);
printf("\n");
print_fun_header("ddf");
print_fun_body(6, polys);
printf("\treturn ("
"q * q * ddp "
"- q * (2.0L * dp * dq + p * ddq) "
"+ 2.0L * p * dq * dq"
") / (q * q * q);\n");
/*printf("\treturn (ddp "
"- 2.0 * ((dp * q - p * dq) / (q * q)) * dq "
"- (p / q) * ddq) / q;\n");*/
print_fun_footer();
poly_free(&dp);
poly_free(&dq);
poly_free(&ddp);
poly_free(&ddq);
}
static unsigned int
parse_uint(const char *s)
{
char *end;
uintmax_t v;
errno = 0;
v = strtoumax(s, &end, 10);
if (s == end || *end != '\0' || errno != 0 || v > UINT_MAX) {
fprintf(stderr, "%s: invalid value: %s\n", argv0, s);
exit(1);
}
return (unsigned int)v;
}
static double
parse_double(const char *s)
{
char *end;
double d;
errno = 0;
d = strtod(s, &end);
if (s == end || *end != '\0' || errno != 0 || !isfinite(d)) {
fprintf(stderr, "%s: invalid value: %s\n", argv0, s);
exit(1);
}
return d;
}
static void
usage(void)
{
fprintf(stderr, "Usage: %s p-degree q-degree p-coefs q-coefs\n"
" %s -n p-degree p-coefs\n", argv0, argv0);
exit(1);
}
static void
do_poly_div(int argc, char *argv[])
{
struct poly p, q;
unsigned int i, j, p_degree, q_degree;
if (argc < 2)
usage();
p_degree = parse_uint(argv[0]);
q_degree = parse_uint(argv[1]);
if (argc != p_degree + q_degree + 2 + 2)
usage();
poly_init(&p, p_degree, "p");
poly_init(&q, q_degree, "q");
for (j = 0, i = 1 + 1 + p.degree + 1 + q.degree;
i > 1 + 1 + p.degree;
i--, j++)
q.coefs[j] = parse_double(argv[i]);
for (j = 0;
i > 1;
i--, j++)
p.coefs[j] = parse_double(argv[i]);
print_funs(p, q);
poly_free(&p);
poly_free(&q);
}
static void
do_newton(int argc, char *argv[])
{
struct poly f, df, p;
unsigned int i, j, f_degree;
if (argc < 1)
usage();
f_degree = parse_uint(argv[0]);
if (argc != f_degree + 1 + 1)
usage();
poly_init(&f, f_degree, "f");
for (j = 0, i = 1 + f.degree;
i > 0;
i--, j++)
f.coefs[j] = parse_double(argv[i]);
poly_derivate(f, &df, "q");
poly_init(&p, f_degree, "p");
for (i = 0; i <= f.degree; i++)
p.coefs[i] = (i == 0 ? 0.0 : df.coefs[i - 1]) - f.coefs[i];
print_funs(p, df);
poly_free(&f);
poly_free(&df);
poly_free(&p);
}
int
main(int argc, char *argv[])
{
struct poly p, q;
char *end;
uintmax_t v;
unsigned int i, j, p_degree, q_degree;
int ch, nflag;
argv0 = argv[0];
nflag = 0;
while ((ch = getopt(argc, argv, "n")) != -1)
switch (ch) {
case 'n':
nflag = 1;
break;
default:
usage();
}
argc -= optind;
argv += optind;
if (nflag)
do_newton(argc, argv);
else
do_poly_div(argc, argv);
return 0;
}

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#!/bin/sh
# fractal
# Written in 2020 by Lucas
# CC0 1.0 Universal/Public domain - No rights reserved
#
# To the extent possible under law, the author(s) have dedicated all
# copyright and related and neighboring rights to this software to the
# public domain worldwide. This software is distributed without any
# warranty. You should have received a copy of the CC0 Public Domain
# Dedication along with this software. If not, see
# <http://creativecommons.org/publicdomain/zero/1.0/>.
usage()
{
printf "Usage: %s width height [fractal args...]\n" "${0##*/}" >&2
exit 1
}
tonumber()
{
printf "%u\n" "$*"
}
width=
height=
if [ $# -lt 2 ] || ! width=$(tonumber "$1") || ! height=$(tonumber "$2"); then
usage
fi
shift 2
upwidth=$((width * 4))
upheight=$((height * 4))
./fractal "$@" -w $upwidth -h $upheight |
pamscale -width $width -height $height |
pamtopng >julia.png

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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <complex.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <math.h>
#include <stdlib.h>
#include <unistd.h>
#include "criticals.h"
#include "palette.h"
#include "pnmout.h"
#include "util.h"
#include "fun.h"
struct color contour_color = { 0 };
static long double bailout = 1e100,
epsilon = 1e-8,
sec_w = 4.0,
contour = 0.0005L;
static unsigned long niters = 250;
static void
print_critical_points(void)
{
long double complex z;
size_t i, n;
n = ncriticals();
fprintf(stderr, "Critical points:\n");
for (i = 0; i < n; i++) {
z = get_critical(i);
fprintf(stderr, "%4zu. (%.20Lf, %.20Lf)\n", i, creall(z),
cimagl(z));
}
}
static int
tends_to_critical(long double complex z, long double *t)
{
long double d;
size_t i, n;
n = ncriticals();
for (i = 0; i < n; i++) {
d = cabsl(z - get_critical(i));
if (d < epsilon) {
*t = d;
return 1;
}
}
return 0;
}
static long
iterate(long double complex z, long double complex c, long double *rit)
{
long double complex dz = 1.0L;
long double t;
unsigned long ci, i;
for (i = 0; i < niters && cabsl(z) < bailout; i++) {
dz = df(z) * dz;
z = f(z) + c;
if (tends_to_critical(z, &t)) {
*rit = logl(logl(t) / logl(epsilon)) / logl(2.0L);
return fabsl(logl(t)) * t < sec_w * contour * cabsl(dz)
? -1 : i;
}
}
t = cabsl(z);
if (t >= bailout) {
*rit = logl(logl(t) / logl(bailout)) / logl(2.0L);
return fabsl(logl(t)) * t < sec_w * contour * cabsl(dz)
? -1 : i;
}
return -1;
}
static long
fast_iterate(long double complex z, long double complex c, long double *rit)
{
long double t;
unsigned long ci, i;
for (i = 0; i < niters && cabsl(z) < bailout; i++) {
z = f(z) + c;
if (tends_to_critical(z, &t)) {
*rit = logl(logl(t) / logl(epsilon)) / logl(2.0L);
return i;
}
}
t = cabsl(z);
if (t >= bailout) {
*rit = logl(logl(t) / logl(bailout)) / logl(2.0L);
return i;
}
return -1;
}
static void
usage(void)
{
fprintf(stderr, "Usage: %s julia [-L] [-x julia_x] [-y julia_y]\n"
" [-n niters] [-h height] [-w width] [-z zoom]\n"
" [-a center_x] [-b center_y] [-l light_intensity]\n"
" [-d density] [-c contour]\n",
xgetprogname());
exit(1);
}
int
julia_main(int argc, char *argv[])
{
struct color *palette;
struct {
long long it;
long double rit;
} *rescache;
char *end;
struct color color;
long double complex crit, julia, z;
long double julia_x = 0.0,
julia_y = 0.0,
cen_x = 0.0,
cen_y = 0.0,
density = 28.3L,
light_intensity = 84.3L,
displacement = 0,
zoom = 1.0,
light, light_x, light_y, light_z, rit, sec_h, zx, zy;
intmax_t v;
long long it, idx, ritnum;
unsigned int palette_size = 720,
width = 640,
height = 400,
i, j;
int ch, do_light = 0;
while ((ch = getopt(argc, argv, "a:b:c:d:h:Ll:n:w:x:y:z:")) != -1)
switch (ch) {
case 'a':
errno = 0;
cen_x = strtold(optarg, &end);
if (end == optarg || *end != '\0' || errno != 0) {
fprintf(stderr, "-a: invalid value \"%s\"",
optarg);
exit(1);
}
break;
case 'b':
errno = 0;
cen_y = strtold(optarg, &end);
if (end == optarg || *end != '\0' || errno != 0) {
fprintf(stderr, "-b: invalid value \"%s\"",
optarg);
exit(1);
}
break;
case 'c':
errno = 0;
contour = strtold(optarg, &end);
if (end == optarg || *end != '\0' || errno != 0
|| contour <= 0) {
fprintf(stderr, "-c: invalid value \"%s\"",
optarg);
exit(1);
}
break;
case 'd':
errno = 0;
density = strtold(optarg, &end);
if (end == optarg || *end != '\0' || errno != 0) {
fprintf(stderr, "-d: invalid value \"%s\"",
optarg);
exit(1);
}
break;
case 'h':
errno = 0;
v = strtoimax(optarg, &end, 0);
if (end == optarg || *end != '\0' || errno != 0 ||
v <= 0 || v >= 65536) {
fprintf(stderr, "-h: invalid value \"%s\"",
optarg);
exit(1);
}
height = (unsigned int)v + 1;
break;
case 'L':
do_light = 1;
break;
case 'l':
errno = 0;
light_intensity = strtold(optarg, &end);
if (end == optarg || *end != '\0' || errno != 0) {
fprintf(stderr, "-l: invalid value \"%s\"",
optarg);
exit(1);
}
break;
case 'n':
errno = 0;
v = strtoimax(optarg, &end, 0);
if (end == optarg || *end != '\0' || errno != 0 ||
v <= 0 || v >= ULONG_MAX) {
fprintf(stderr, "-n: invalid value \"%s\"",
optarg);
exit(1);
}
niters = (unsigned long)v;
break;
case 'w':
errno = 0;
v = strtoimax(optarg, &end, 0);
if (end == optarg || *end != '\0' || errno != 0 ||
v <= 0 || v >= 65536) {
fprintf(stderr, "-w: invalid value \"%s\"",
optarg);
exit(1);
}
width = (unsigned int)v + 1;
break;
case 'x':
errno = 0;
julia_x = strtold(optarg, &end);
if (end == optarg || *end != '\0' || errno != 0) {
fprintf(stderr, "-x: invalid value \"%s\"",
optarg);
exit(1);
}
break;
case 'y':
errno = 0;
julia_y = strtold(optarg, &end);
if (end == optarg || *end != '\0' || errno != 0) {
fprintf(stderr, "-y: invalid value \"%s\"",
optarg);
exit(1);
}
break;
case 'z':
errno = 0;
zoom = strtold(optarg, &end);
if (end == optarg || *end != '\0' || errno != 0
|| zoom <= 0) {
fprintf(stderr, "-z: invalid value \"%s\"",
optarg);
exit(1);
}
break;
default:
usage();
}
argc -= optind;
argv += optind;
if (argc > 1)
usage();
palette = palette_gen(palette_size);
if ((rescache = malloc(sizeof(*rescache) * width * height)) == NULL) {
fprintf(stderr, "out of memory\n");
exit(1);
}
if (do_light) {
long double angle_xy, angle_z;
angle_xy = drand48() * 2.0L * 3.14159265358979323846L;
angle_z = (0.2L + 0.6L * drand48()) * 3.14159265358979323846L;
light_x = cosl(angle_xy) * sinl(angle_z);
light_y = sinl(angle_xy) * sinl(angle_z);
light_z = cosl(angle_z);
}
sec_h = sec_w * height / (long double)width;
julia = julia_x + I * julia_y;
for (i = 0; i < height; i++) {
zy = cen_y + (0.5 - i / (long double)height) * sec_h;
for (j = 0; j < width; j++) {
zx = cen_x + (j / (long double)width - 0.5L) * sec_w;
z = zx + I * zy;
if (behaves_critical(df, ddf, z, &crit, bailout,
epsilon))
add_critical_point(crit);
}
}
print_critical_points();
sec_w /= zoom; sec_h /= zoom;
for (i = 0; i < height; i++) {
zy = cen_y + (0.5L - i / (long double)height) * sec_h;
for (j = 0; j < width; j++) {
zx = cen_x + (j / (long double)width - 0.5L) * sec_w;
z = zx + I * zy;
it = iterate(z, julia, &rit);
rescache[i * width + j].it = it;
rescache[i * width + j].rit = rit;
}
}
pnmout_header(stdout, width - 1, height - 1);
for (i = 0; i < height - 1; i++) {
for (j = 0; j < width - 1; j++) {
it = rescache[i * width + j].it;
rit = rescache[i * width + j].rit;
if (it < 0)
color = contour_color;
else {
ritnum = (it - rit) * density;
if (do_light) {
long double lxrn, lyrn, l, lx, ly, lz;
lxrn = rescache[i * width + j + 1].it
- rescache[i * width + j + 1].rit;
lyrn = rescache[(i + 1) * width + j].it
- rescache[(i + 1) * width + j].rit;
lx = -sec_h * (lxrn - it + rit);
ly = sec_w * (lyrn - it + rit);
lz = sec_w * sec_h;
l = sqrtl(lx * lx + ly * ly + lz * lz);
light = (light_x * lx + light_y * ly
+ light_z * lz) / l;
ritnum += light * light_intensity;
}
idx = (long long)ritnum
+ 1000000 * palette_size + displacement;
color = palette[idx % palette_size
+ (idx < 0 ? palette_size : 0)];
}
pnmout_pixel(stdout, color);
}
}
free(rescache);
free(palette);
return !(fflush(stdout) == 0);
}

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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include "palette.h"
#include "pnmout.h"
#include "util.h"
#define CLAMP(x, a, b) ((x) < (a) ? (a) : (x) > (b) ? (b) : (x))
static double
bezier3(double t, double p0, double p1, double p2, double p3)
{
double u = 1.0 - t;
return u * u * u * p0
+ 3.0 * u * u * t * p1
+ 3.0 * u * t * t * p2
+ t * t * t * p3;
}
static double
bezier4(double t, double p0, double p1, double p2, double p3)
{
return (1.0 - t) * bezier3(t, p0, p1, p2, p3)
+ t * bezier3(t, p1, p2, p3, p0);
}
struct color *
palette_gen(size_t n)
{
struct color *palette;
double p[12] = {
drand48(), drand48(), drand48(),
drand48(), drand48(), drand48(),
drand48(), drand48(), drand48(),
drand48(), drand48(), drand48(),
};
double r, g, b, t;
size_t i;
if (!(palette = malloc(n * sizeof(*palette)))) {
fprintf(stderr, "out of memory");
exit(1);
}
for (i = 0; i < n; i++) {
t = i / (double)n;
r = bezier4(t, p[0], p[3], p[6], p[9]);
g = bezier4(t, p[1], p[4], p[7], p[10]);
b = bezier4(t, p[2], p[5], p[8], p[11]);
palette[i].r = 65535.0 * CLAMP(r, 0.0, 1.0);
palette[i].g = 65535.0 * CLAMP(g, 0.0, 1.0);
palette[i].b = 65535.0 * CLAMP(b, 0.0, 1.0);
}
return palette;
}
static void
usage(void)
{
fprintf(stderr, "Usage: %s palette [-h height] [-w width]\n",
xgetprogname());
exit(1);
}
int
palette_main(int argc, char *argv[])
{
struct color *palette;
char *end;
uintmax_t v;
unsigned int width, height;
int ch, i, j;
height = 100;
width = 720;
while ((ch = getopt(argc, argv, "h:w:")) != -1)
switch (ch) {
case 'h':
errno = 0;
v = strtoumax(optarg, &end, 0);
if (*end != '\0' || errno != 0 || v == 0
|| v > UINT_MAX) {
fprintf(stderr, "-h: Invalid value \"%s\"",
optarg);
exit(1);
}
height = v;
case 'w':
errno = 0;
v = strtoumax(optarg, &end, 0);
if (*end != '\0' || errno != 0 || v == 0
|| v > UINT_MAX) {
fprintf(stderr, "-w: Invalid value \"%s\"",
optarg);
exit(1);
}
width = v;
default:
usage();
}
argc -= optind;
argv += optind;
if (argc > 1)
usage();
palette = palette_gen(width);
pnmout_header(stdout, width, height);
for (i = 0; i < height; i++)
for (j = 0; j < width; j++)
pnmout_pixel(stdout, palette[j]);
free(palette);
return !(fflush(stdout) == 0);
}

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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <stddef.h>
#include <stdint.h>
struct color {
uint16_t r, g, b;
};
struct color * palette_gen(size_t);
int palette_main(int, char *[]);

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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include "palette.h"
#include "pnmout.h"
void
pnmout_header(FILE *fp, unsigned int width, unsigned int height)
{
if (fprintf(fp, "P6\n%u %u 255\n", width, height) < 0) {
perror("fprintf");
exit(1);
}
}
void
pnmout_pixel(FILE *fp, struct color c)
{
uint8_t v[3];
v[0] = c.r / 256;
v[1] = c.g / 256;
v[2] = c.b / 256;
if (fwrite(v, sizeof(v[0]), sizeof(v) / sizeof(v[0]), fp) != 3) {
perror("fwrite");
exit(1);
}
}

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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <stdio.h>
void pnmout_header(FILE *, unsigned int, unsigned int);
void pnmout_pixel(FILE *, struct color);

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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include <stdlib.h>
const char *
xgetprogname(void)
{
#if defined(__OpenBSD__)
return getprogname();
#else
extern char *__progname;
return __progname;
#endif
}
void
xsrand48(long seed)
{
#if defined(__OpenBSD__)
srand48_deterministic(seed);
#else
srand48(seed);
#endif
}

16
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/*
* fractal
* Written in 2020 by Lucas
* CC0 1.0 Universal/Public domain - No rights reserved
*
* To the extent possible under law, the author(s) have dedicated all
* copyright and related and neighboring rights to this software to the
* public domain worldwide. This software is distributed without any
* warranty. You should have received a copy of the CC0 Public Domain
* Dedication along with this software. If not, see
* <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#define nelems(_a) (sizeof((_a)) / sizeof((_a)[0]))
const char * xgetprogname(void);
void xsrand48(long);