To help you get started, we've collected the most common ways that @mapbox/tiny-sdf is being used within popular public projects.

uber / deck.gl / modules / layers / src / text-layer / font-atlas.js View on Github

const fontHeight = fontSize * HEIGHT_SCALE;
  const {canvasHeight, mapping} = buildMapping({
    ctx,
    fontHeight,
    buffer,
    characterSet,
    maxCanvasWidth: MAX_CANVAS_WIDTH
  });

  canvas.width = MAX_CANVAS_WIDTH;
  canvas.height = canvasHeight;
  setTextStyle(ctx, fontFamily, fontSize, fontWeight);

  // layout characters
  if (sdf) {
    const tinySDF = new TinySDF(fontSize, buffer, radius, cutoff, fontFamily, fontWeight);
    // used to store distance values from tinySDF
    const imageData = ctx.createImageData(tinySDF.size, tinySDF.size);

    for (const char of characterSet) {
      populateAlphaChannel(tinySDF.draw(char), imageData);
      ctx.putImageData(imageData, mapping[char].x - buffer, mapping[char].y - buffer);
    }
  } else {
    for (const char of characterSet) {
      ctx.fillText(char, mapping[char].x, mapping[char].y + fontSize * BASELINE_SCALE);
    }
  }

  return {
    scale: HEIGHT_SCALE,
    mapping,

View more ways to use @mapbox/tiny-sdf

TinySDF

TinySDF is a tiny and fast JavaScript library for generating SDF (signed distance field) from system fonts on the browser using Canvas 2D and Felzenszwalb/Huttenlocher distance transform. This is very useful for rendering text with WebGL.

Demo

Usage

Create a TinySDF for drawing glyph SDFs based on font parameters:

const tinySdf = new TinySDF({
    fontSize: 24,             // Font size in pixels
    fontFamily: 'sans-serif', // CSS font-family
    fontWeight: 'normal',     // CSS font-weight
    fontStyle: 'normal',      // CSS font-style
    buffer: 3,                // Whitespace buffer around a glyph in pixels
    radius: 8,                // How many pixels around the glyph shape to use for encoding distance
    cutoff: 0.25              // How much of the radius (relative) is used for the inside part of the glyph
});

const glyph = tinySdf.draw('泽'); // draw a single character

Returns an object with the following properties:

• data is a Uint8ClampedArray array of alpha values (0–255) for a width x height grid.
• width: Width of the returned bitmap.
• height: Height of the returned bitmap.
• glyphTop: Maximum ascent of the glyph from alphabetic baseline.
• glyphLeft: Currently hardwired to 0 (actual glyph differences are encoded in the rasterization).
• glyphWidth: Width of the rasterized portion of the glyph.
• glyphHeight Height of the rasterized portion of the glyph.
• glyphAdvance: Layout advance.

TinySDF is provided as a ES module, so it's only supported on modern browsers, excluding IE.

In Node, you can't use require — only import in ESM-capable versions (v12.15+):

import TinySDF from '@mapbox/tiny-sdf';

Development

npm test  # run tests
npm start # start server for the demo page

License

This implementation is licensed under the BSD 2-Clause license. It's based directly on the algorithm published in the Felzenszwalb/Huttenlocher paper, and is not a port of the existing C++ implementation provided by the paper's authors.