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dala2.c
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dala2.c
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/* dala2 --- plot an HPGL mandala 2011-09-10 */
/* Copyright (c) 2011 John Honniball, Froods Software Development */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <unistd.h>
#include "hpgllib.h"
void catcher(int sig);
/* Central disc patterns */
double lissajous(const double x0, const double y0, double side, const double f1, const double f2, const double theta, const int npts);
double spiraldisc(const double x0, const double y0, const double radius, const int n, const int turns);
double sunflowerspiral(const double x0, const double y0, const double radius);
double lotus(const double x0, const double y0, double radius, const int nleaves, const int nlayers);
double diamondsquare(const double x0, const double y0, double side);
/* Intermediate ring patterns */
double zigzagring(const double x0, const double y0, const double r1, const double r2, const int npts, const int incr, const int flag);
double radials(const double x0, const double y0, const double inner, const double length, const int n);
double ringoboxes(const double x0, const double y0, const double radius, const int nboxes, const int ninner);
double circlediamonds(const double x0, const double y0, double radius, const int ndiam);
double ringofcircles(const double x0, const double y0, double radius, const int ncirc);
double sqwavering(const double x0, const double y0, const double radius, const double len, int nwaves);
double ellipsering(const double x0, const double y0, const double a, const double b, const int nell);
double ringofpoly(const double x0, const double y0, const double radius, const int nside, const int npoly);
double circlering(const double x0, const double y0, const double r1, const double r2, const int n);
/* Outer circle-to-square transitions */
double circletosuper(const double x0, const double y0, const double r1, const double r2, const int n);
double sqradials(const double x0, const double y0, const double r1, const double r2, const int n);
void curvestitchtrans(const double x0, const double y0, const double r1, const double r2, const int n);
/* Square border drawing functions */
void saltireborder(const double x0, const double y0, const int nx, const int ny, const double w, const double h);
void roundrectborder(const double x0, const double y0, const double r1, const double r2, const int n);
void circleborder(const double x0, const double y0, const int nx, const int ny, const double w, const double h);
void celticstepborder(const double x0, const double y0, const int nx, const int ny, const double w, const double h);
/* Utility drawing functions */
void radialfan(const double x0, const double y0, const double r1, const double startangle, const double dx, const double dy, const double xvec, const double yvec, const int n);
void spiral(const double cx, const double cy, const double radius, const double ang, const int n);
void bordergrid(const double x0, const double y0, const double w, const double h, const int nx, const int ny, const int diag);
void superellipse(const double x0, const double y0, const double a, const double b, const double theta, const double d);
double lotuszigzag(const double x0, const double y0, const double r1, const double r2, const int npts, const int flag);
void drawstep(const double x0, const double y0, const double w, const double h, const int flipx, const int flipy);
int main(int argc, char * const argv[])
{
int opt;
double xc, yc;
double maxx, maxy;
double height;
double radius;
double inner_r;
double scale = 40.0;
while ((opt = getopt(argc, argv, "no:p:s:t:v:")) != -1) {
switch (opt) {
case 's':
if (strchr(optarg, '1'))
scale = 80.0;
else if (strchr(optarg, '2'))
scale = 56.57;
else if (strchr(optarg, '4'))
scale = 28.28;
else if (strchr(optarg, '5'))
scale = 20.0;
case 'n':
case 'o':
case 'p':
case 't':
case 'v':
plotopt (opt, optarg);
break;
default: /* '?' */
fprintf(stderr, "Usage: %s [-p pen] [-s <size>] [-t title]\n", argv[0]);
fprintf(stderr, " <size> ::= A1 | A2 | A3 | A4 | A5\n");
exit(EXIT_FAILURE);
}
}
if (plotbegin(0) < 0) {
fputs("Failed to initialise HPGL library\n", stderr);
exit(EXIT_FAILURE);
}
getplotsize(&maxx, &maxy);
xc = maxx / 2.0;
yc = maxy / 2.0;
height = maxy;
/* Draw square border */
rectangle(xc - (height / 2.0), 0.0, xc + (height / 2.0), maxy);
radius = 20.0 * scale;
/* Draw central spirals */
// radius = spiraldisc(xc, yc, radius, 3, 2);
radius = lotus(xc, yc, radius, 16, 7);
// radius = lissajous(xc, yc, 38.0 * scale, 3.0, 4.0, 0.0, 144);
/* Plot ring of ellipses around spirals */
circle(xc, yc, radius);
radius = ellipsering(xc, yc, radius + (1.0 * scale), radius + (9.0 * scale), 3);
radius += 1.0 * scale;
/* Pre-draw circles around zigzags */
circle(xc, yc, radius);
circle(xc, yc, radius + (50.0 * scale));
/* Plot radial lines */
radius = radials(xc, yc, radius, 5.0 * scale, 63);
/* Plot two rings of zigzags */
radius = zigzagring(xc, yc, radius, radius + (20.0 * scale), 63, 4, 0);
radius = zigzagring(xc, yc, radius, radius + (25.0 * scale), 63, 8, 1);
/* Plot steampunk cog */
// radius = sqwavering(xc, yc, radius + (2.0 * scale), 12.0 * scale, 18);
/* Plot ring of concentric boxes */
radius = ringoboxes(xc, yc, radius + (2.0 * scale), 48, 3);
/* Plot ring of polygons */
// radius = ringofpoly(xc, yc, radius + (12.0 * scale), 7, 5);
/* Plot circle with diamonds */
circle(xc, yc, radius + (2.0 * scale));
radius = circlediamonds(xc, yc, radius + (2.0 * scale), 36);
circle(xc, yc, radius);
radius += 2.0 * scale;
/* Plot superellipses with increasingly sharp corners */
// circletosuper(xc, yc, radius, height / 2.0, 6);
// sqradials(xc, yc, radius, height / 2.0, 160);
// circlering(xc, yc, radius, height / 2.0, 4);
// ringofcircles(xc, yc, radius, 96);
inner_r = (height / 2.0) - (height / 12.0);
// circle(xc, yc, inner_r);
curvestitchtrans(xc, yc, radius, inner_r, 20);
/* Draw a square border pattern */
// roundrectborder(xc, yc, inner_r, height / 2.0, 5);
// saltireborder(xc - (height / 2.0), 0.0, 12, 12, height / 12.0, height / 12.0);
// circleborder(xc - (height / 2.0), 0.0, 12, 12, height / 12.0, height / 12.0);
celticstepborder(xc - (height / 2.0), 0.0, 12, 12, height / 12.0, height / 12.0);
plotend();
return (0);
}
/* lissajous --- draw a lissajous pattern */
double lissajous(const double x0, const double y0, double side, const double f1, const double f2, const double theta, const int npts)
{
const double delta = (2.0 * M_PI) / (double)npts;
const double sintheta = sin(theta);
const double costheta = cos(theta);
double r;
int i;
side /= 2.0;
r = side;
for (i = 0; i <= npts; i++) {
const double t = (double)i * delta;
const double t1 = t * f1;
const double t2 = t * f2;
const double x = (r * cos(t1) * costheta) - (r * sin(t2) * sintheta);
const double y = (r * cos(t1) * sintheta) + (r * sin(t2) * costheta);
if (i == 0)
moveto(x0 + x, y0 + y);
else
lineto(x0 + x, y0 + y);
}
/* Return radius of circumscribing circle */
return (sqrt((side * side) * 2.0));
}
/* spiraldisc --- draw multiple spirals from a common centre point */
double spiraldisc(const double x0, const double y0, const double radius, const int n, const int turns)
{
int i;
const double delta = (M_PI * 2.0) / (double)n;
for (i = 0; i < n; i++) {
const double theta = (double)i * delta;
spiral(x0, y0, radius, theta, turns);
}
return (radius);
}
/* diamondsquare --- draw concentric squares at 45-degree offsets */
double diamondsquare(const double x0, const double y0, double side)
{
side /= 2.0;
/* Plot outer square */
rectangle(x0 - side, y0 - side, x0 + side, y0 + side);
/* Plot inner diagonal square */
moveto(x0, y0 - side);
lineto(x0 + side, y0);
lineto(x0, y0 + side);
lineto(x0 - side, y0);
lineto(x0, y0 - side);
/* Return radius of circumscribing circle */
return (sqrt((side * side) * 2.0));
}
/* zigzagring --- draw a ring of zigzags */
double zigzagring(const double x0, const double y0, const double r1, const double r2, const int npts, const int incr, const int flag)
{
int i;
double x1[128], y1[128];
double x2[128], y2[128];
double theta1, theta2;
const double delta = (2.0 * M_PI) / (double)npts;
int n1, n2;
for (i = 0; i < npts; i++) {
if (flag) {
theta2 = delta * (double)i;
theta1 = (delta * (double)i) + (delta / 2.0);
}
else {
theta1 = delta * (double)i;
theta2 = (delta * (double)i) + (delta / 2.0);
}
x1[i] = (cos(theta1) * r1) + x0;
y1[i] = (sin(theta1) * r1) + y0;
x2[i] = (cos(theta2) * r2) + x0;
y2[i] = (sin(theta2) * r2) + y0;
}
moveto(x1[0], y1[0]);
n1 = 0;
n2 = incr / 2;
for (i = 0; i < npts; i++) {
lineto(x1[n1], y1[n1]);
lineto(x2[n2], y2[n2]);
n1 = (n1 + incr) % npts;
n2 = (n2 + incr) % npts;
}
lineto(x1[0], y1[0]);
return (r2);
}
/* radials --- draw simple radial lines */
double radials(const double x0, const double y0, const double inner, const double length, const int n)
{
int i;
const double delta = (2.0 * M_PI) / (double)n;
for (i = 0; i < n; i++) {
const double theta = (double)i * delta;
const double xvec = cos(theta);
const double yvec = sin(theta);
const double x1 = xvec * inner;
const double y1 = yvec * inner;
const double x2 = xvec * (inner + length);
const double y2 = yvec * (inner + length);
if (i & 1) {
moveto(x0 + x1, y0 + y1);
lineto(x0 + x2, y0 + y2);
}
else {
moveto(x0 + x2, y0 + y2);
lineto(x0 + x1, y0 + y1);
}
}
return (inner + length);
}
double ringoboxes(const double x0, const double y0, const double radius, const int nboxes, const int ninner)
{
int i, j, k;
double side, s2;
const double delta = (2.0 * M_PI) / (double)nboxes;
double x[4], y[4];
double rx[4], ry[4];
double inc;
side = (2.0 * M_PI * radius) / (double)nboxes;
side *= 0.8;
s2 = side / 2.0;
inc = s2 / (double)ninner;
for (i = 0; i < nboxes; i++) {
const double theta = (double)i * delta;
const double s = sin(theta);
const double c = cos(theta);
for (k = 0; k < ninner; k++) {
/* Set up a square */
x[0] = -s2;
y[0] = -s2;
x[1] = s2;
y[1] = -s2;
x[2] = s2;
y[2] = s2;
x[3] = -s2;
y[3] = s2;
/* Shrink, rotate and translate square */
for (j = 0; j < 4; j++) {
if (x[j] < 0)
x[j] += k * inc;
else
x[j] -= k * inc;
if (y[j] < 0)
y[j] += k * inc;
else
y[j] -= k * inc;
rx[j] = (x[j] * c) - (y[j] * s);
ry[j] = (x[j] * s) + (y[j] * c);
rx[j] += x0 + (c * (radius + s2));
ry[j] += y0 + (s * (radius + s2));
}
/* Draw the rotated square */
moveto(rx[0], ry[0]);
lineto(rx[1], ry[1]);
lineto(rx[2], ry[2]);
lineto(rx[3], ry[3]);
lineto(rx[0], ry[0]);
}
}
return (radius + side);
}
double circlediamonds(const double x0, const double y0, double radius, const int ndiam)
{
int i;
const double delta = (M_PI * 2.0) / (double)ndiam;
const double diag = (2.0 * M_PI * radius) / (double)ndiam;
double r1, r2;
double x1[128], y1[128];
double x2[128], y2[128];
radius += diag / 2.0;
circle (x0, y0, radius);
r1 = radius - (diag / 2.0);
r2 = radius + (diag / 2.0);
for (i = 0; i < ndiam; i++) {
const double theta = (double)i * delta;
x1[i] = (r1 * cos(theta)) + x0;
y1[i] = (r1 * sin(theta)) + y0;
x2[i] = (r2 * cos(theta)) + x0;
y2[i] = (r2 * sin(theta)) + y0;
}
moveto(x1[0], y1[0]);
for (i = 0; i < ndiam; i++) {
if (i & 1)
lineto(x2[i], y2[i]);
else
lineto(x1[i], y1[i]);
}
lineto(x1[0], y1[0]);
moveto(x2[0], y2[0]);
for (i = 0; i < ndiam; i++) {
if (i & 1)
lineto(x1[i], y1[i]);
else
lineto(x2[i], y2[i]);
}
lineto(x2[0], y2[0]);
return (r2);
}
/* ringofpoly --- draw overlapping polygons to form a ring */
double ringofpoly(const double x0, const double y0, const double radius, const int nside, const int npoly)
{
int i, j;
const double delta = (M_PI * 2.0) / (double)npoly;
const double angperside = (M_PI * 2.0) / (double)nside;
for (i = 0; i < npoly; i++) {
const double theta = (double)i * delta;
double x = radius * cos(theta);
double y = radius * sin(theta);
moveto(x0 + x, y0 + y);
for (j = 0; j < nside; j++) {
const double intang = (double)(j + 1) * angperside;
x = radius * cos(theta + intang);
y = radius * sin(theta + intang);
lineto(x0 + x, y0 + y);
}
}
return (radius);
}
double ringofcircles(const double x0, const double y0, double radius, const int ncirc)
{
const double delta = (M_PI * 2.0) / (double)ncirc;
double r2;
int i;
/* Compute radius as if centres are on circumference of 'radius' */
r2 = radius * sin(delta);
/* Increase radius by radius of small circles */
radius += r2;
/* Recompute radius of smaller circles */
r2 = radius * sin(delta);
for (i = 0; i < ncirc; i++) {
const double theta = (double)i * delta;
const double x = radius * cos(theta);
const double y = radius * sin(theta);
circle2(x0 + x, y0 + y, r2, 10.0);
}
return (radius + r2);
}
/* sqwavering --- draw a cog-like ring of square waves */
double sqwavering(const double x0, const double y0, const double radius, const double len, int nwaves)
{
double delta;
double degrees;
int i;
/* Number of half-waves; must be even */
nwaves *= 2;
delta = (2.0 * M_PI) / (double)nwaves;
degrees = 360.0 / (double)nwaves;
for (i = 0; i < nwaves; i++) {
const double theta = (double)i * delta;
const double xvec = cos(theta);
const double yvec = sin(theta);
const double x1 = xvec * radius;
const double y1 = yvec * radius;
const double x2 = xvec * (radius + len);
const double y2 = yvec * (radius + len);
if (i == 0)
moveto(x0 + x2, y0 + y2);
if (i & 1)
lineto(x0 + x2, y0 + y2);
else
lineto(x0 + x1, y0 + y1);
arc(x0, y0, degrees);
}
return (radius + len);
}
double ellipsering(const double x0, const double y0, const double a, const double b, const int nell)
{
const double delta = M_PI / (double)nell;
int i;
for (i = 0; i < nell; i++)
ellipse(x0, y0, a, b, delta * i);
if (a > b)
return (a);
else
return (b);
}
/* circletosuper --- draw transition from circle to superellipses */
double circletosuper(const double x0, const double y0, const double r1, const double r2, const int n)
{
static double pow2[6] = {
2.8, 4.0, 5.65, 8.0, 11.3, 16.0
};
const double step = (r2 - r1) / (double)n;
int i;
for (i = 0; i < n; i++) {
const double a = r1 + (i * step);
const double b = r1 + (i * step);
superellipse(x0, y0, a, b, 0.0, pow2[i]);
}
return (r2);
}
double circlering(const double x0, const double y0, const double r1, const double r2, const int n)
{
int i;
const double delta = (M_PI * 2.0) / (double)n;
const double r = (r2 - r1) / 2.0;
for (i = 0; i < n; i++) {
const double theta = (double)i * delta;
const double x = r * cos(theta);
const double y = r * sin(theta);
circle(x0 + x, y0 + y, r1 + r);
}
return (r2);
}
/* sqradials --- draw radial lines from inner circle to outer square */
double sqradials(const double x0, const double y0, const double r1, const double r2, const int n)
{
const double side = 2.0 * r2; /* Length of side of overall square */
const double r45 = M_PI / 4.0; /* 45 degrees in radians */
radialfan(x0, y0, r1, r45, r2, r2, -side, 0.0, n / 4);
radialfan(x0, y0, r1, r45 * 3.0, -r2, r2, 0.0, -side, n / 4);
radialfan(x0, y0, r1, r45 * 5.0, -r2, -r2, side, 0.0, n / 4);
radialfan(x0, y0, r1, r45 * 7.0, r2, -r2, 0.0, side, n / 4);
return (r2);
}
/* roundrectborder --- draw border as nested rounded rectangles */
void roundrectborder(const double x0, const double y0, const double r1, const double r2, const int n)
{
int i;
const double incr = (r2 - r1) / (double)n;
/* Innermost rectangle does not have rounded corners */
rectangle(x0 - r1, y0 - r1, x0 + r1, y0 + r1);
for (i = 1; i < n; i++) {
const double radius = incr * (double)i;
const double xmin = x0 - r1 - radius;
const double ymin = y0 - r1 - radius;
const double xmax = x0 + r1 + radius;
const double ymax = y0 + r1 + radius;
roundrect(xmin, ymin, xmax, ymax, radius);
}
}
/* saltireborder --- draw border squares as saltires */
void saltireborder(const double x0, const double y0, const int nx, const int ny, const double w, const double h)
{
/* nx and ny must be even, but need not be equal */
const double xmax = x0 + (nx * w);
const double ymax = y0 + (ny * h);
int i;
bordergrid (x0, y0, w, h, nx, ny, 1);
/* Zig-zag across bottom */
moveto(x0, y0 + (2.0 * h));
lineto(x0 + (2.0 * w), y0);
for (i = 3; i < (nx - 1); i += 2) {
lineto(x0 + (i * w), y0 + h);
lineto(x0 + ((i + 1) * w), y0);
}
/* Zig-zag up RHS */
lineto(xmax, y0 + (2.0 * h));
for (i = 3; i < (ny - 1); i += 2) {
lineto(xmax - w, y0 + (i * h));
lineto(xmax, y0 + ((i + 1) * h));
}
/* Zig-zag across top, R to L */
lineto(xmax - (2.0 * w), ymax);
for (i = nx - 3; i > 1; i -= 2) {
lineto(x0 + (i * w), ymax - h);
lineto(x0 + ((i - 1) * w), ymax);
}
/* Zig-zag down LHS */
lineto(x0, ymax - (2.0 * h));
for (i = ny - 3; i > 1; i -= 2) {
lineto(x0 + w, y0 + (i * h));
lineto(x0, y0 + ((i - 1) * h));
}
/* Zig-zag across bottom again, L to R */
moveto(x0, y0 + h);
lineto(x0 + w, y0);
for (i = 2; i < nx; i += 2) {
lineto(x0 + (i * w), y0 + h);
lineto(x0 + ((i + 1) * w), y0);
}
/* Zig-zag up RHS */
lineto(xmax, y0 + h);
for (i = 2; i < ny; i += 2) {
lineto(xmax - w, y0 + (i * h));
lineto(xmax, y0 + ((i + 1) * h));
}
/* Zig-zag across top, R to L */
lineto(xmax - w, ymax);
for (i = nx - 2; i > 1; i -= 2) {
lineto(x0 + (i * w), ymax - h);
lineto(x0 + ((i - 1) * w), ymax);
}
/* Zig-zag down LHS */
lineto(x0, ymax - h);
for (i = ny - 2; i > 1; i -= 2) {
lineto(x0 + w, y0 + (i * h));
lineto(x0, y0 + ((i - 1) * h));
}
}
/* circleborder --- draw border squares as circles */
void circleborder(const double x0, const double y0, const int nx, const int ny, const double w, const double h)
{
/* w and h must be the same for the circles to fit in the grid */
const double xmax = x0 + (nx * w);
const double ymax = y0 + (ny * h);
int i;
bordergrid(x0, y0, w, h, nx, ny, 0);
for (i = 1; i < nx; i++) {
circle(x0 + (w / 2.0) + (w * (double)i), h / 2.0, h / 2.0);
}
for (i = 1; i < ny; i++) {
circle(xmax - (w / 2.0), y0 + (h / 2.0) + (h * (double)i), h / 2.0);
}
for (i = nx - 2; i >= 0; i--) {
circle(x0 + (w / 2.0) + (w * (double)i), ymax - (h / 2.0), h / 2.0);
}
for (i = ny - 2; i >= 0; i--) {
circle(x0 + (w / 2.0), y0 + (h / 2.0) + (h * (double)i), h / 2.0);
}
}
/* celticstepborder --- draw a border grid of Celtic step pattern */
void celticstepborder(const double x0, const double y0, const int nx, const int ny, const double w, const double h)
{
const double xmax = x0 + (nx * w);
const double ymax = y0 + (ny * h);
int i;
bordergrid(x0, y0, w, h, nx, ny, 0);
for (i = 1; i < nx; i++) {
drawstep(x0 + (w * (double)i), y0, w, h, i & 1, 0);
}
for (i = 1; i < ny; i++) {
drawstep(xmax - w, y0 + (h * (double)i), w, h, 1, i & 1);
}
for (i = nx - 2; i >= 0; i--) {
drawstep(x0 + (w * (double)i), ymax - h, w, h, i & 1, 1);
}
for (i = ny - 2; i >= 0; i--) {
drawstep(x0, y0 + (h * (double)i), w, h, 0, i & 1);
}
}
/* curvestitchtrans --- transition by curve-stiching (pin-and-cotton) */
void curvestitchtrans(const double x0, const double y0, const double r1, const double r2, const int n)
{
int i;
double xmin, xmax;
double ymin, ymax;
const double xinc = r2 / (double)n;
const double yinc = r2 / (double)n;
/* Draw lower RH corner */
xmin = x0;
ymin = y0 - r2;
xmax = x0 + r2;
ymax = y0;
for (i = 1; i < n; i++) {
if (i & 1) {
moveto(xmin + (xinc * (double)i), ymin);
lineto(xmax, ymin + (yinc * (double)i));
}
else {
moveto(xmax, ymin + (yinc * (double)i));
lineto(xmin + (xinc * (double)i), ymin);
}
}
/* Draw upper RH corner */
xmin = x0;
ymin = y0;
xmax = x0 + r2;
ymax = y0 + r2;
for (i = 1; i < n; i++) {
if (i & 1) {
moveto(xmax, ymin + (yinc * (double)i));
lineto(xmax - (xinc * (double)i), ymax);
}
else {
moveto(xmax - (xinc * (double)i), ymax);
lineto(xmax, ymin + (yinc * (double)i));
}
}
/* Draw upper LH corner */
xmin = x0 - r2;
ymin = y0;
xmax = x0;
ymax = y0 + r2;
for (i = 1; i < n; i++) {
if (i & 1) {
moveto(xmax - (xinc * (double)i), ymax);
lineto(xmin, ymax - (yinc * (double)i));
}
else {
moveto(xmin, ymax - (yinc * (double)i));
lineto(xmax - (xinc * (double)i), ymax);
}
}
/* Draw lower LH corner */
xmin = x0 - r2;
ymin = y0 - r2;
xmax = x0;
ymax = y0;
for (i = 1; i < n; i++) {
if (i & 1) {
moveto(xmin, ymax - (yinc * (double)i));
lineto(xmin + (xinc * (double)i), ymin);
}
else {
moveto(xmin + (xinc * (double)i), ymin);
lineto(xmin, ymax - (yinc * (double)i));
}
}
}
void radialfan(const double x0, const double y0, const double r1, const double startangle, const double dx, const double dy, const double xvec, const double yvec, const int n)
{
int i;
const double delta1 = (M_PI / 2.0) / (double)n;
const double delta2 = 1.0 / (double)n;
for (i = 0; i < n; i++) {
const double theta = startangle + ((double)i * delta1);
const double x1 = x0 + (r1 * cos(theta));
const double y1 = y0 + (r1 * sin(theta));
const double x2 = x0 + dx + (xvec * ((double)i * delta2));
const double y2 = y0 + dy + (yvec * ((double)i * delta2));
if (i & 1) {
moveto(x1, y1);
lineto(x2, y2);
}
else {
moveto(x2, y2);
lineto(x1, y1);
}
}
}
/* bordergrid --- draw grid around page with optional diagonals in corners */
void bordergrid(const double x0, const double y0, const double w, const double h, const int nx, const int ny, const int diag)
{
const double xmax = x0 + (nx * w);
const double ymax = y0 + (ny * h);
int i;
/* Draw four lines in the form of #, in optimum sequence */
moveto(x0 + w, y0);
lineto(x0 + w, ymax);
moveto(x0, ymax - h);
lineto(xmax, ymax - h);
moveto(xmax - w, ymax);
lineto(xmax - w, y0);
moveto(xmax, y0 + h);
lineto(x0, y0 + h);
/* Draw remainder of grid, along the bottom */
for (i = 2; i < (nx - 1); i++) {
moveto(x0 + (i * w), y0);
lineto(x0 + (i * w), y0 + h);
}
/* Draw lower RH corner diagonal */
if (diag) {
moveto(xmax, y0);
lineto(xmax - w, y0 + h);
}
/* Up the right-hand side */
for (i = 2; i < (ny - 1); i++) {
moveto(xmax, y0 + (i * h));
lineto(xmax - w, y0 + (i * h));
}
/* Draw upper RH corner diagonal */
if (diag) {
moveto(xmax, ymax);
lineto(xmax - w, ymax - h);
}
/* Along the top, leftwards */
for (i = nx - 2; i > 1; i--) {
moveto(x0 + (i * w), ymax);
lineto(x0 + (i * w), ymax - h);
}
/* Draw upper LH corner diagonal */
if (diag) {
moveto(x0, ymax);
lineto(x0 + w, ymax - h);
}
/* Left-hand side, downwards */
for (i = ny - 2; i > 1; i--) {
moveto(x0, y0 + (i * h));
lineto(x0 + w, y0 + (i * h));
}
/* Draw lower LH corner diagonal */
if (diag) {
moveto(x0, y0);
lineto(x0 + w, y0 + h);
}
}
/* superellipse --- draw a superellipse */
void superellipse(const double x0, const double y0, const double a, const double b, const double theta, const double d)
{
const int npts = 72;
const double delta = (2.0 * M_PI) / (double)npts;
const double sintheta = sin(theta);
const double costheta = cos(theta);
int i;
for (i = 0; i <= npts; i++) {
double sinpt, cospt;
const double t = (double)i * delta;
const double st = sin(t);
const double ct = cos(t);
if (st < 0.0)
sinpt = -pow(-st, 2.0 / d);
else
sinpt = pow(st, 2.0 / d);
if (ct < 0.0)
cospt = -pow(-ct, 2.0 / d);
else
cospt = pow(ct, 2.0 / d);
const double x = (a * cospt * costheta) - (b * sinpt * sintheta);
const double y = (a * cospt * sintheta) + (b * sinpt * costheta);
if (i == 0)
moveto(x0 + x, y0 + y);
else
lineto(x0 + x, y0 + y);
}
}
/* spiral --- draw a spiral given angle and number of turns */
void spiral(const double cx, const double cy, const double radius, const double ang, const int n)
{
double delta = 2.0 * M_PI / 72.0;
int i;
int npts = 72 * n;
moveto(cx, cy);
for (i = 1; i <= npts; i++) {
const double theta = ang + (delta * (double)i);
const double r = (radius * i) / (double)npts;
const double x = (r * cos(theta)) + cx;
const double y = (r * sin(theta)) + cy;
lineto(x, y);
}
}
/* lotus --- draw a central disc in the form of a lotus pattern */
double lotus(const double x0, const double y0, double radius, const int nleaves, const int nlayers)
{