Add support of Unicode Variation Sequence for 0 that adds a slash (#1534).

changes/17.2.0.md

@@ -0,0 +1 @@
+* Add support of Unicode Variation Sequence for `0` that adds a slash (#1534).

font-src/gen/finalize/gc.mjs

@@ -1,4 +1,11 @@
-import { Radical } from "../../support/gr.mjs";
+import { Radical, VS01 } from "../../support/gr.mjs";
+
+export function gcFont(glyphStore, excludedChars, otl, cfg) {
+	markSweepOtlLookups(otl.GSUB);
+	markSweepOtlLookups(otl.GPOS);
+	const sink = markGlyphs(glyphStore, excludedChars, otl, cfg);
+	return sweepGlyphs(glyphStore, sink);
+}
 
 function markSweepOtlLookups(table) {
 	if (!table || !table.features || !table.lookups) return;
@@ -56,6 +63,7 @@ function sweepFeatures(table, accessibleLookupsIds) {
 	}
 	table.features = features1;
 }
+
 function markGlyphs(glyphStore, excludedChars, otl, cfg) {
 	const sink = markGlyphsInitial(glyphStore, excludedChars);
 	while (markGlyphsStep(glyphStore, sink, otl, cfg));
@@ -78,6 +86,9 @@ function markGlyphsInitial(glyphStore, excludedChars) {
 }
 function markGlyphsStep(glyphStore, sink, otl, cfg) {
 	const glyphCount = sink.size;
+	for (const g of glyphStore.glyphs()) {
+		markLinkedGlyph(sink, g, VS01);
+	}
 	if (otl.GSUB) {
 		for (const l in otl.GSUB.lookups) {
 			const lookup = otl.GSUB.lookups[l];
@@ -88,6 +99,10 @@ function markGlyphsStep(glyphStore, sink, otl, cfg) {
 	const glyphCount1 = sink.size;
 	return glyphCount1 > glyphCount;
 }
+function markLinkedGlyph(sink, g, gr) {
+	const linked = gr.get(g);
+	if (linked) sink.add(linked);
+}
 function markGlyphsLookupImpl(sink, lookup, cfg) {
 	switch (lookup.type) {
 		case "gsub_single":
@@ -136,12 +151,7 @@ function markGlyphsGsubReverse(sink, lookup, cfg) {
 		}
 	}
 }
-function sweep(glyphStore, gnSet) {
+
+function sweepGlyphs(glyphStore, gnSet) {
 	return glyphStore.filterByName(gnSet);
 }
-export function gcFont(glyphStore, excludedChars, otl, cfg) {
-	markSweepOtlLookups(otl.GSUB);
-	markSweepOtlLookups(otl.GPOS);
-	const sink = markGlyphs(glyphStore, excludedChars, otl, cfg);
-	return sweep(glyphStore, sink);
-}

font-src/gen/otd-conv/glyphs.mjs

@@ -122,10 +122,13 @@ class MappedGlyphStore {
 		g.geometry = cs;
 	}
 }
+
 export function convertGlyphs(gsOrig) {
 	const sortedEntries = Array.from(gsOrig.namedEntries(Gr.Nwid, Gr.Wwid)).sort(byRank);
 	const gs = new MappedGlyphStore();
 	const cmap = new Ot.Cmap.Table();
+
+	// initialize
 	for (const [name, gSrc] of sortedEntries) {
 		gs.declare(name, gSrc);
 		const us = gsOrig.queryUnicodeOf(gSrc);
@@ -137,7 +140,36 @@ export function convertGlyphs(gsOrig) {
 			}
 		}
 	}
+
+	// fill geometry
 	for (const [name, gSrc] of sortedEntries) gs.fill(name, gSrc);
+
+	// fill VS
+	addVsLinks(gsOrig, gs, cmap, Gr.VS01, 0xfe00);
+
+	// fill glyph names
 	gs.fillOtGlyphNames();
+
 	return { glyphs: gs, cmap };
 }
+
+function addVsLinks(gsOrig, gs, cmap, gr, vs) {
+	for (const gSrc of gsOrig.glyphs()) {
+		const us = gsOrig.queryUnicodeOf(gSrc);
+		if (!us) continue;
+
+		const gnSrcLinked = gr.get(gSrc);
+		if (!gnSrcLinked) continue;
+
+		const gSrcLinked = gsOrig.queryByName(gnSrcLinked);
+		if (!gSrcLinked) continue;
+
+		const gDstLinked = gs.queryBySourceGlyph(gSrcLinked);
+		if (!gDstLinked) continue;
+
+		for (const u of us) {
+			if (!(isFinite(u - 0) && u)) continue;
+			cmap.vs.set(u, vs, gDstLinked);
+		}
+	}
+}

font-src/glyphs/number/0.ptl

@@ -1,7 +1,7 @@
 $$include '../../meta/macros.ptl'
 
 import [mix linreg clamp fallback] from"../../support/utils.mjs"
-import [AnyCv getGrMesh] from"../../support/gr.mjs"
+import [AnyCv getGrMesh VS01] from"../../support/gr.mjs"
 
 glyph-module
 
@@ -120,6 +120,9 @@ glyph-block Digits-Zero : begin
 	select-variant 'zero.lnum/forceUnslashed' (follow -- 'zero/forceUnslashed') (shapeFrom -- 'zero.lnum')
 	select-variant 'zero.onum/forceUnslashed' (follow -- 'zero/forceUnslashed') (shapeFrom -- 'zero.onum')
 
+	if [query-glyph 'zero.lnum'] : VS01.set [query-glyph 'zero.lnum'] 'zero.lnum/forceSlashed'
+	if [query-glyph 'zero.onum'] : VS01.set [query-glyph 'zero.onum'] 'zero.onum/forceSlashed'
+
 	glyph-block-import Letter-Blackboard : BBS BBD
 	create-glyph 'mathbb/zero' 0x1D7D8 : glyph-proc
 		include : MarkSet.capital

font-src/support/gr.mjs

@@ -19,6 +19,7 @@ export const Dotless = {
 export const LowerYDotAtBelow = LinkedGlyphProp("LowerYDotAtBelow");
 export const DependentSelector = LinkedGlyphProp("DependentSelector");
 export const MathSansSerif = LinkedGlyphProp("MathSansSerif");
+export const VS01 = LinkedGlyphProp("VS01");
 function LinkedGlyphProp(key) {
 	return {
 		get(glyph) {