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More efficient font rendering. #8

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dcd3f83
Smaller more efficient rendering
Jun 12, 2025
aaeee25
Replace if with and
Jun 12, 2025
ed5e340
add dist
Jun 12, 2025
88d1b96
Skip more blank cells
Jun 16, 2025
3450eef
A few bytes larger renderer, but vastly more efficient
Jun 16, 2025
fa8c1b9
Add comment to while loop optimization
Jun 16, 2025
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57 changes: 31 additions & 26 deletions dist/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -13,32 +13,37 @@ const initFont = ({ height=DEFAULT_CHAR_HEIGHT, ...chars }={}, ctx) => {
return
}

const bin2arr = (bin, width) => bin.match(new RegExp(`.{${width}}`, 'g'));
const isNumber = code => code > 0;

return (string, x=0, y=0, size=24, color=DEFAULT_COLOR) => {
const renderChar = (charX, char) => {
const pixelSize = size/height;
const fontCode = chars[char.charCodeAt()] || '';
const binaryChar = isNumber(fontCode) ? fontCode : fontCode.codePointAt();

const binary = (binaryChar || 0).toString(2);

const width = Math.ceil(binary.length / height);
const marginX = charX + pixelSize;
const formattedBinary = binary.padStart(width * height, 0);
const binaryCols = bin2arr(formattedBinary, height);

console.debug('Rendering char', char, char.charCodeAt(), fontCode, binaryChar, binaryCols);

binaryCols.map((column, colPos) =>
[...column].map((pixel, pixPos) => {
ctx.fillStyle = !+pixel ? 'transparent' : color; // pixel == 0 ?
ctx.fillRect(x + marginX + colPos * pixelSize, y + pixPos * pixelSize, pixelSize, pixelSize);
})
);

return charX + (width+1)*pixelSize
return ( string, x = 0, y = 0, size = 24, color = DEFAULT_COLOR ) => {
const pixelSize = size / height;
const renderChar = ( charX, char ) => {
const fontCode = chars[ char.charCodeAt() ] || '';
let bin = Number.isInteger( fontCode ) ? fontCode : fontCode.codePointAt();
const binary = ( bin || 0 ).toString( 2 );
const width = Math.ceil( binary.length / height );
const mask = ( 1 << height ) - 1;

ctx.fillStyle = color;
for ( let col = width; col > 0; col-- ) {
let rowPos = height - 1;
for ( let row = bin & mask; row > 0; row >>= 1 ) {
if ( row & 1 ) {
let y1 = y + rowPos * pixelSize, h = pixelSize;

while ( ( row >> 1 ) & 1 ) {
y1 -= pixelSize;
h += pixelSize;
row >>= 1;
rowPos--;
}

ctx.fillRect( x + charX + col * pixelSize, y1, pixelSize, h );
}
rowPos--;
}
bin >>= height;
}

return charX + ( width + 1 ) * pixelSize;
};

console.debug('Rendering string', string);
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2 changes: 1 addition & 1 deletion dist/tinyfont-font-pixel.min.js
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2 changes: 1 addition & 1 deletion dist/tinyfont-font-tiny.min.js
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59 changes: 33 additions & 26 deletions src/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -11,32 +11,39 @@ export const initFont = ({ height=DEFAULT_CHAR_HEIGHT, ...chars }={}, ctx) => {
return
}

const bin2arr = (bin, width) => bin.match(new RegExp(`.{${width}}`, 'g'));
const isNumber = code => code > 0;

return (string, x=0, y=0, size=24, color=DEFAULT_COLOR) => {
const renderChar = (charX, char) => {
const pixelSize = size/height;
const fontCode = chars[char.charCodeAt()] || '';
const binaryChar = isNumber(fontCode) ? fontCode : fontCode.codePointAt();

const binary = (binaryChar || 0).toString(2);

const width = Math.ceil(binary.length / height);
const marginX = charX + pixelSize;
const formattedBinary = binary.padStart(width * height, 0);
const binaryCols = bin2arr(formattedBinary, height);

console.debug('Rendering char', char, char.charCodeAt(), fontCode, binaryChar, binaryCols);

binaryCols.map((column, colPos) =>
[...column].map((pixel, pixPos) => {
ctx.fillStyle = !+pixel ? 'transparent' : color; // pixel == 0 ?
ctx.fillRect(x + marginX + colPos * pixelSize, y + pixPos * pixelSize, pixelSize, pixelSize);
})
);

return charX + (width+1)*pixelSize
return ( string, x = 0, y = 0, size = 24, color = DEFAULT_COLOR ) => {
const pixelSize = size / height;
const renderChar = ( charX, char ) => {
const fontCode = chars[ char.charCodeAt() ] || '';
let bin = Number.isInteger( fontCode ) ? fontCode : fontCode.codePointAt();
const binary = ( bin || 0 ).toString( 2 );
const width = Math.ceil( binary.length / height );
const mask = ( 1 << height ) - 1;

ctx.fillStyle = color;
for ( let col = width; col > 0; col-- ) {
let rowPos = height - 1;
for ( let row = bin & mask; row > 0; row >>= 1 ) {
if ( row & 1 ) {
let y1 = y + rowPos * pixelSize, h = pixelSize;

// This while loop greatly reduces the amount of draw calls.
// If you need a few more bytes, you could remove this.
while ( ( row >> 1 ) & 1 ) {
y1 -= pixelSize;
h += pixelSize;
row >>= 1;
rowPos--;
}

ctx.fillRect( x + charX + col * pixelSize, y1, pixelSize, h );
}
rowPos--;
}
bin >>= height;
}

return charX + ( width + 1 ) * pixelSize;
};

console.debug('Rendering string', string);
Expand Down