autokerning/dist/cli.js

autokerning computes suggested kerning values for glyph pairs from TrueType/OpenType fonts by rendering glyph bitmaps, applying a small Gaussian blur, and measuring pixel overlap across horizontal offsets. It can be used programmatically (as an imported E

#!/usr/bin/env node
import { Command } from "commander";
import * as opentype from "opentype.js";
import { renderGlyph } from "./glyph.js";
import { kernPair } from "./kernPair.js";
import { generateKerningTable, findS } from "./generateKerningTable.js";
const program = new Command();
program
    .name("autokerning")
    .description("Auto-compute kerning values for fonts")
    .argument("<fontfile>", "Path to font file (.ttf/.otf)")
    .argument("[pairs...]")
    .option("-s, --size <n>", "Font size (default 100)", "100")
    .option("-o, --output <file>", "Generate kerning JSON file like generate-kerning")
    .option("--pairs <list>", "Comma-separated list of pairs to analyze for JSON output")
    .parse(process.argv);
const fontfile = program.args[0];
let pairs = program.args.slice(1);
const outputFile = program.opts().output;
const pairsString = program.opts().pairs;
// Convert comma-separated pairs string to array
const pairsList = pairsString
    ? pairsString.split(",").map((p) => p.trim())
    : undefined;
import { COMMON_PAIRS } from "./commonPairs.js";
// use findS exported from generateKerningTable (calibrated adaptive kernel)
(async () => {
    if (outputFile) {
        // Generate kerning JSON file for font, optionally with user pairs
        const { outputPath, kerningTable } = await generateKerningTable(fontfile, {
            outputfile: outputFile,
            pairs: pairsList,
            writeFile: true,
        });
        console.log(`Kerning table saved to: ${outputPath}`);
        console.log(`Total pairs: ${Object.keys(kerningTable).length}`);
        return;
    }
    // If no pairs provided, use default common pairs
    if (!pairs.length) {
        pairs = COMMON_PAIRS;
    }
    const font = await opentype.load(fontfile);
    // Calibrate overlap thresholds (findS returns [minS, maxS, kernelWidth])
    const [minS, maxS, kernelWidth] = findS(font);
    for (const pair of pairs) {
        if (pair.length !== 2)
            continue;
        const [lch, rch] = pair;
        const left = renderGlyph(font, lch);
        const right = renderGlyph(font, rch);
        const kern = kernPair(left, right, minS, maxS, kernelWidth);
        console.log(`${pair}: suggested kerning ${kern.toFixed(2)} (px)`);
    }
})();