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Brooke Vibber 2023-08-19 12:54:28 -07:00
parent 555a34b4db
commit 605e6d04b9
1 changed files with 46 additions and 45 deletions
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87
index.html
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@ -74,11 +74,29 @@
return Array.from(block).map((n) => n.toString(16)).join('');
}
function inverse(block) {
return block.map((n) => ~n & 0xf);
function inverse(pixel) {
return ~pixel & 0xf;
}
function drawChar(bits, cx, cy, char, charset) {
function matchBlocks(a, b, threshold) {
for (let i = 0; i < blockWidth * blockHeight; i++) {
if (Math.abs(a[i] - b[i]) > threshold) {
return false;
}
}
return true;
}
function matchBlocksInverse(a, b, threshold) {
for (let i = 0; i < blockWidth * blockHeight; i++) {
if (Math.abs(a[i] - inverse(b[i])) > threshold) {
return false;
}
}
return true;
}
function drawChar(imageData, cx, cy, char, charset) {
let invert = Boolean(char & 0x80);
char &= 0x7f;
if (char >= charset.length) {
@ -88,16 +106,16 @@
for (let y = 0; y < blockHeight; y++) {
for (let x = 0; x < blockWidth; x++) {
let i = y * blockWidth + x;
let ii = (y + cy * blockHeight) * bits.width + (x + cx * blockWidth);
let ii = (y + cy * blockHeight) * imageData.width + (x + cx * blockWidth);
let gray16 = block[i];
if (invert) {
gray16 = ~gray16 & 0x0f;
gray16 = inverse(gray16);
}
let gray256 = Math.round(gray16 * 255 / 15);
bits.data[ii * 4] = gray256;
bits.data[ii * 4 + 1] = gray256;
bits.data[ii * 4 + 2] = gray256;
bits.data[ii * 4 + 3] = 255;
imageData.data[ii * 4] = gray256;
imageData.data[ii * 4 + 1] = gray256;
imageData.data[ii * 4 + 2] = gray256;
imageData.data[ii * 4 + 3] = 255;
}
}
}
@ -146,36 +164,12 @@
//
// First pass: uniques extraction
// Convert the 4bpp pixel indices into hex strings
let blockMap = {};
let uniques = [];
/*
for (let i = 0; i < chars.length; i++) {
let char = chars[i];
let block = blocks[char];
let key = hexify(blocks[i]);
let keyInverse = hexify(inverse(block));
if (blockMap[key]) {
char = blockMap[key];
} else if (blockMap[keyInverse]) {
char = blockMap[keyInverse];
} else {
char = uniques.push(block) - 1;
blockMap[key] = char;
blockMap[keyInverse] = char;
}
chars[i] = char;
}
*/
for (let threshold = 0; threshold < 16; threshold++) {
charIter:
for (let i = 0; i < chars.length; i++) {
let char = chars[i];
let block = blocks[char];
if (!block) {
debugger
throw new Error('missing block');
}
for (let i = 0; i < blocks.length; i++) {
let block = blocks[i];
fontMatch:
for (let j = 0; j < uniques.length; j++) {
@ -184,14 +178,16 @@
debugger
throw new Error('missing other');
}
for (let k = 0; k < blockWidth * blockHeight; k++) {
if (Math.abs(block[k] - other[k]) > threshold) {
continue fontMatch;
}
}
if (matchBlocks(block, other, threshold)) {
// we're close enough to reuse a character
chars[i] = j;
continue charIter;
} else if (matchBlocksInverse(block, other, threshold)) {
chars[i] = j | 0x8000;
continue charIter;
} else {
continue fontMatch;
}
}
// add a new char
chars[i] = uniques.push(block) - 1;
@ -200,13 +196,12 @@
break;
}
// We need to decimate further
blocks = uniques;
uniques = [];
}
let span = document.querySelector('#block-count');
span.textContent = `${uniques.length}`;
// Font (currently wrong! :D)
// Font
let fontCtx = document.querySelector('#font').getContext('2d');
let font = fontCtx.createImageData(16 * blockWidth, 16 * blockHeight);
for (let hi = 0; hi < 16; hi++) {
@ -222,7 +217,13 @@
for (let cy = 0; cy < heightBlocks; cy++) {
for (let cx = 0; cx < widthBlocks; cx++) {
let i = cy * widthBlocks + cx;
drawChar(bits, cx, cy, chars[i], uniques);
let char = chars[i];
if (char & 0x8000) {
// we use a bigger bit during earlier stages
char &= 0x7f;
char |= 0x80;
}
drawChar(bits, cx, cy, char, uniques);
}
}
ctx.putImageData(bits, 0, 0);