example sine ncurses tempalte

lib/sine.c

@@ -0,0 +1,125 @@
+#include <math.h>
+#include <ncurses.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define DEFAULT_AMPLITUDE 1
+#define DEFAULT_PERIOD .35
+#define DEFAULT_DELAY_MULTIPLIER 150
+#define BASE_DELAY 100
+
+// Color count
+#define NUM_COLORS 6
+
+typedef unsigned short ushort;
+
+ushort printwave(double amplitude, double period, short phase_shift,
+                 ushort color_index) {
+
+  double x;
+  for (x = 0.0; x < (COLS + phase_shift); x += 1.0) {
+
+    // Swap color
+    color_index += 1;
+    attron(COLOR_PAIR((color_index % NUM_COLORS) + 1));
+
+    // Find Y
+    double ratio = (2.0 * M_PI) / LINES;
+    double y = sin(period * x * ratio);
+    y *= amplitude;
+    y += LINES / 2;
+
+    // Print cell
+    mvprintw((int)(y), (int)(x - phase_shift), " ");
+  }
+
+  return color_index;
+}
+
+int main(int argc, char *argv[]) {
+  // Curses init
+  WINDOW *screen = initscr();
+  start_color();
+  nodelay(screen, 1);
+  cbreak();
+  noecho();
+  curs_set(0);
+  keypad(screen, TRUE);
+
+  // Color pairs
+  init_pair(1, COLOR_RED, COLOR_BLACK);
+  init_pair(2, COLOR_GREEN, COLOR_BLACK);
+  init_pair(3, COLOR_YELLOW, COLOR_BLACK);
+  init_pair(4, COLOR_BLUE, COLOR_BLACK);
+  init_pair(5, COLOR_MAGENTA, COLOR_BLACK);
+  init_pair(6, COLOR_CYAN, COLOR_BLACK);
+  init_pair(7, COLOR_WHITE, COLOR_BLACK);
+  attron(A_BOLD);
+  attron(A_STANDOUT);
+
+  // Wave attributes
+  unsigned char delayx = DEFAULT_DELAY_MULTIPLIER;
+  ushort color_index = 0;
+  short phase_shift = 0;
+  double amplitude = (LINES / 2) * DEFAULT_AMPLITUDE;
+  double period = DEFAULT_PERIOD;
+
+  while (1) {
+
+    erase();
+
+    color_index = printwave(amplitude, period, phase_shift, color_index);
+
+    attron(COLOR_PAIR(7));
+    mvprintw(0, 0, "PERIOD %.2f", period);
+    mvprintw(1, 0, "AMP: %.2f", amplitude);
+    mvprintw(2, 0, "PHASE: %d", phase_shift);
+    mvprintw(3, 0, "DELAY: x%hu", delayx);
+
+    refresh();
+
+    switch (getch()) {
+    case KEY_UP:
+    case 'k':
+      amplitude += 1.0;
+      break;
+    case KEY_DOWN:
+    case 'j':
+      amplitude -= 1.0;
+      break;
+    case KEY_LEFT:
+    case 'h':
+      period -= .05;
+      break;
+    case KEY_RIGHT:
+    case 'l':
+      period += .05;
+      break;
+    case ' ':
+      phase_shift = 0.0;
+      break;
+    case '+':
+      delayx += 1;
+      break;
+    case '-':
+      delayx -= 1;
+      break;
+    case 'q':
+      endwin();
+      return 0;
+    default:
+      break;
+    }
+
+    usleep(BASE_DELAY * delayx);
+
+    phase_shift += 1;
+
+    if (phase_shift * period >= LINES)
+      phase_shift = 0;
+  }
+
+  endwin();
+  return 0;
+}