initial commit

.gitignore

+spiro
+.vscode

Makefile

+spiro: spiro.c
+	gcc -o spiro spiro.h spiro.c -lncurses -lm

spiro.c

+#include "spiro.h"
+
+int scale(double pixel)
+{
+	return round((pixel / 2 + 0.5) * LINES);
+}
+
+void plot(double R, double r, double O)
+{
+	for (int tn = 0; tn < T_MAX * RESOLUTION; tn++)
+	{
+		double t = M_PI * tn / RESOLUTION;
+		int x = scale((R - r) * cos(t) + O * cos((R - r) / r * t));
+		int y = scale((R - r) * sin(t) - O * sin((R - r) / r * t));
+		if (x < 0 || x >= COLS || y < 0 || y >= LINES)
+			continue;
+		mvaddch(y, x, '.');
+	}
+}
+
+void clearscr()
+{
+	for (int x = 0; x < COLS; x++)
+	{
+		for (int y = 0; y < LINES; y++)
+		{
+			mvaddch(y, x, ' ');
+		}
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	initscr();
+	while (1)
+	{
+		for (double R = 1; R >= 0; R -= 0.1)
+		{
+			for (double r = 0; r <= 1; r += 0.1)
+			{
+				for (double O = 0; O <= 1; O += 0.1)
+				{
+					char buf[50];
+					plot(R, r, O);
+					sprintf(buf, "R=%.2f r=%.2f O=%.2f", R, r, O);
+					mvaddstr(0, COLS - strlen(buf), buf);
+					refresh();
+					clearscr();
+				}
+			}
+		}
+	}
+	endwin();
+}

spiro.h

+#include <curses.h>
+#include <unistd.h>
+#include <string.h>
+
+#ifndef __USE_MISC
+#define __USE_MISC
+#endif
+
+#include <math.h>
+
+// number of pixels in the range t=(0, PI)
+#define RESOLUTION 1000
+// defines the maximum value of t = T_MAX*PI
+#define T_MAX 1000
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