Add braille

1 files changed, 67 insertions, 0 deletions

diff --git a/braille.js b/braille.js
new file mode 100644
index 0000000..8d94db7
--- /dev/null
+++ b/braille.js
@@ -0,0 +1,67 @@
+"use strict";
+
+const OUTHEIGHT = 20;
+const OUTWIDTH = 2 * OUTHEIGHT;
+const HEIGHT = 3 * OUTHEIGHT;
+const WIDTH = 2 * OUTWIDTH;
+const BRAILLE = [
+  "⠀", "⠁", "⠂", "⠃", "⠄", "⠅", "⠆", "⠇", "⠈", "⠉", "⠊", "⠋", "⠌", "⠍", "⠎", "⠏",
+  "⠐", "⠑", "⠒", "⠓", "⠔", "⠕", "⠖", "⠗", "⠘", "⠙", "⠚", "⠛", "⠜", "⠝", "⠞", "⠟",
+  "⠠", "⠡", "⠢", "⠣", "⠤", "⠥", "⠦", "⠧", "⠨", "⠩", "⠪", "⠫", "⠬", "⠭", "⠮", "⠯",
+  "⠰", "⠱", "⠲", "⠳", "⠴", "⠵", "⠶", "⠷", "⠸", "⠹", "⠺", "⠻", "⠼", "⠽", "⠾", "⠿",
+];
+
+let board = new Array(HEIGHT);
+for (let i = 0; i < HEIGHT; i++) {
+  board[i] = new Array(WIDTH);
+}
+
+function render(board) {
+  const out = new Array(OUTHEIGHT);
+  for (let i = 0; i < OUTHEIGHT; i++) {
+    out[i] = new Array(OUTWIDTH);
+  }
+  for (let y = 0; y < HEIGHT; y += 3) {
+    for (let x = 0; x < WIDTH; x += 2) {
+      let outx = x/2;
+      let outy = y/3;
+      let tl = board[y][x] ? 1 : 0;
+      let ml = board[y+1][x] ? 1 : 0;
+      let bl = board[y+2][x] ? 1 : 0;
+      let tr = board[y][x+1] ? 1 : 0;
+      let mr = board[y+1][x+1] ? 1 : 0;
+      let br = board[y+2][x+1] ? 1 : 0;
+      let idx = tl*1 + ml*2 +  bl*4 + tr*8 + mr*16 + br*32;
+      let char = BRAILLE[idx];
+      out[outy][outx] = char;
+    }
+  }
+  return out.reduce((a, r) => a + r.reduce((a2, c) => a2 + c) + "\n", "");
+}
+
+function renderFunction(board, fun, frame) {
+  for (let y = 0; y < HEIGHT; y++) {
+    for (let x = 0; x < WIDTH; x++) {
+      board[y][x] = fun(x, y, frame) ? true : null;
+    }
+  }
+  return render(board);
+}
+
+function fun(x, y, frame) {
+  const l = HEIGHT / 3;
+  const m1 = Math.abs(y+frame) % l;
+  const m2 = Math.abs(y-frame) % l;
+  return x == m1 ||
+    x == m2 ||
+    x/2 == m1 + l/2 ||
+    x/2 == m2 + l/2 ||
+    x == m1 + 3*l ||
+    x == m2 + 3*l;
+}
+
+const br = document.getElementById("braille");
+let frame = HEIGHT;
+const interval = setInterval(() => {
+  br.innerHTML = renderFunction(board, fun, frame++);
+}, 50);