Iosevka/font-src/gen/finalize/glyphs.js

"use strict";

const TypoGeom = require("typo-geom");
const Geom = require("../../support/geometry");
const Point = require("../../support/point");
const Transform = require("../../support/transform");
const CurveUtil = require("../../support/curve-util");
const util = require("util");

module.exports = finalizeGlyphs;
function finalizeGlyphs(cache, para, glyphStore) {
	const skew = Math.tan(((para.slopeAngle || 0) / 180) * Math.PI);
	regulateGlyphStore(cache, skew, glyphStore);
	return glyphStore;
}

///////////////////////////////////////////////////////////////////////////////////////////////////

function regulateGlyphStore(cache, skew, glyphStore) {
	for (const g of glyphStore.glyphs()) {
		if (g.geometry.isEmpty()) continue;
		if (!regulateCompositeGlyph(glyphStore, g)) flattenSimpleGlyph(cache, skew, g);
	}
}

///////////////////////////////////////////////////////////////////////////////////////////////////

function regulateCompositeGlyph(glyphStore, g) {
	const refs = g.geometry.asReferences();
	if (!refs) return false;
	for (const sr of refs) {
		const gn = glyphStore.queryNameOf(sr.glyph);
		if (!gn || sr.glyph.autoRefPriority < 0) return false;
	}
	return true;
}

function flattenSimpleGlyph(cache, skew, g) {
	const ck = Geom.hashGeometry(g.geometry);
	const cached = cache.getGF(ck);
	if (ck && cached) {
		g.clearGeometry();
		g.includeContours(CurveUtil.repToShape(cached), 0, 0);
		cache.saveGF(ck, cached);
	} else {
		const tfBack = new Transform(1, -skew, 0, 1, 0, 0);
		const tfForward = new Transform(1, +skew, 0, 1, 0, 0);
		const g1 = new Geom.TransformedGeometry(
			new SimplifyGeometry(new Geom.TransformedGeometry(g.geometry, tfBack)),
			tfForward
		);
		const cs = g1.asContours();
		g.clearGeometry();
		g.includeContours(cs, 0, 0);
		if (ck) cache.saveGF(ck, CurveUtil.shapeToRep(cs));
	}
}

///////////////////////////////////////////////////////////////////////////////////////////////////

class SimplifyGeometry extends Geom.GeometryBase {
	constructor(g) {
		super();
		this.m_geom = g;
	}
	asContours() {
		const source = this.m_geom.asContours();
		const sink = new FairizedShapeSink();
		TypoGeom.ShapeConv.transferGenericShape(
			TypoGeom.Fairize.fairizeBezierShape(
				TypoGeom.Boolean.removeOverlap(
					CurveUtil.convertShapeToArcs(source),
					TypoGeom.Boolean.PolyFillType.pftNonZero,
					CurveUtil.BOOLE_RESOLUTION
				)
			),
			sink,
			CurveUtil.GEOMETRY_PRECISION
		);
		return sink.contours;
	}
	asReferences() {
		return null;
	}
	filterTag(fn) {
		return this.m_geom.filterTag(fn);
	}
	isEmpty() {
		return this.m_geom.isEmpty();
	}
	measureComplexity() {
		return this.m_geom.measureComplexity();
	}
	toShapeStringOrNull() {
		const sTarget = this.m_geom.toShapeStringOrNull();
		if (!sTarget) return null;
		return `SimplifyGeometry{${sTarget}}`;
	}
}

class FairizedShapeSink {
	constructor() {
		this.contours = [];
		this.lastContour = [];
	}
	beginShape() {}
	endShape() {
		if (this.lastContour.length > 2) {
			// TT use CW for outline, being different from Clipper
			const c = this.lastContour.reverse();
			const zFirst = c[0],
				zLast = c[c.length - 1];
			if (isOccurrent(zFirst, zLast)) c.pop();
			this.contours.push(c);
		}
		this.lastContour = [];
	}
	moveTo(x, y) {
		this.endShape();
		this.lineTo(x, y);
	}
	lineTo(x, y) {
		const z = Point.fromXY(Point.Type.Corner, x, y).round(1);
		this.popOccurrentKnots(z);
		this.popColinearKnots(z);
		this.lastContour.push(z);
	}
	arcTo(arc, x, y) {
		const offPoints = TypoGeom.Quadify.auto(arc, 1, 8);
		for (const z of offPoints) {
			this.lastContour.push(Point.from(Point.Type.Quadratic, z).round(1));
		}
		this.lineTo(x, y);
	}
	popOccurrentKnots(z) {
		if (this.lastContour.length <= 0) return;
		const last = this.lastContour[this.lastContour.length - 1];
		if (last.type === Point.Type.Corner && last.x === z.x && last.y === z.y) {
			this.lastContour.pop();
		}
	}
	popColinearKnots(z) {
		let kArcStart = this.lastContour.length - 2;
		if (kArcStart >= 0) {
			const kLast = kArcStart + 1;
			if (
				this.lastContour[kArcStart].type !== Point.Type.Corner &&
				this.lastContour[kLast].type === Point.Type.Corner
			) {
				return;
			}
		}
		while (kArcStart >= 0 && this.lastContour[kArcStart].type !== Point.Type.Corner)
			kArcStart--;
		if (kArcStart >= 0) {
			const a = this.lastContour[kArcStart];
			let fColinearH = true;
			let fColinearV = true;
			for (let m = kArcStart + 1; m < this.lastContour.length; m++) {
				const b = this.lastContour[m];
				if (!(aligned(a.y, b.y, z.y) && between(a.x, b.x, z.x))) fColinearH = false;
				if (!(aligned(a.x, b.x, z.x) && between(a.y, b.y, z.y))) fColinearV = false;
			}
			if (fColinearH || fColinearV) this.lastContour.length = kArcStart + 1;
		}
	}
}
function isOccurrent(zFirst, zLast) {
	return (
		zFirst.type === Point.Type.Corner &&
		zLast.type === Point.Type.Corner &&
		zFirst.x === zLast.x &&
		zFirst.y === zLast.y
	);
}
function geometryPrecisionEqual(a, b) {
	return Math.round(a) === Math.round(b);
}
function aligned(a, b, c) {
	return geometryPrecisionEqual(a, b) && geometryPrecisionEqual(b, c);
}
function between(a, b, c) {
	return (a <= b && b <= c) || (a >= b && b >= c);
}