Feature/ccmp (#688)

Implement ccmp feature execution, enabling muti character emoji support
opentypejs · Apr 10, 2024 · be0d441 · be0d441
1 parent ce5fcce
commit be0d441
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Showing 10 changed files with 272 additions and 2 deletions.
diff --git a/src/bidi.js b/src/bidi.js
@@ -9,6 +9,8 @@ import arabicWordCheck from './features/arab/contextCheck/arabicWord.js';
 import arabicSentenceCheck from './features/arab/contextCheck/arabicSentence.js';
 import arabicPresentationForms from './features/arab/arabicPresentationForms.js';
 import arabicRequiredLigatures from './features/arab/arabicRequiredLigatures.js';
+import ccmpReplacementCheck from './features/ccmp/contextCheck/ccmpReplacement.js';
+import ccmpReplacement from './features/ccmp/ccmpReplacementLigatures.js';
 import latinWordCheck from './features/latn/contextCheck/latinWord.js';
 import latinLigature from './features/latn/latinLigatures.js';
 import thaiWordCheck from './features/thai/contextCheck/thaiWord.js';
@@ -42,6 +44,7 @@ Bidi.prototype.setText = function (text) {
  * arabic sentence check for adjusting arabic layout
  */
 Bidi.prototype.contextChecks = ({
+    ccmpReplacementCheck,
     latinWordCheck,
     arabicWordCheck,
     arabicSentenceCheck,
@@ -64,6 +67,7 @@ function registerContextChecker(checkId) {
  * tokenize text input
  */
 function tokenizeText() {
+    registerContextChecker.call(this, 'ccmpReplacement');
     registerContextChecker.call(this, 'latinWord');
     registerContextChecker.call(this, 'arabicWord');
     registerContextChecker.call(this, 'arabicSentence');
@@ -160,6 +164,18 @@ function applyArabicPresentationForms() {
     }
 }
 
+/**
+ * Apply ccmp replacement
+ */
+function applyCcmpReplacement() {
+    checkGlyphIndexStatus.call(this);
+    const ranges = this.tokenizer.getContextRanges('ccmpReplacement');
+    for(let i = 0; i < ranges.length; i++) {
+        const range = ranges[i];
+        ccmpReplacement.call(this, range);
+    }
+}
+
 /**
  * Apply required arabic ligatures
  */
@@ -223,6 +239,9 @@ Bidi.prototype.checkContextReady = function (contextId) {
  * https://learn.microsoft.com/en-us/typography/opentype/spec/features_ae#tag-ccmp
  */
 Bidi.prototype.applyFeaturesToContexts = function () {
+    if (this.checkContextReady('ccmpReplacement')) {
+        applyCcmpReplacement.call(this);
+    }
     if (this.checkContextReady('arabicWord')) {
         applyArabicPresentationForms.call(this);
         applyArabicRequireLigatures.call(this);

diff --git a/src/features/applySubstitution.js b/src/features/applySubstitution.js
@@ -30,6 +30,15 @@ function chainingSubstitutionFormat3(action, tokens, index) {
     for(let i = 0; i < action.substitution.length; i++) {
         const subst = action.substitution[i];
         const token = tokens[index + i];
+        if (Array.isArray(subst)) {
+            if (subst.length){
+                // TODO: replace one glyph with multiple glyphs
+                token.setState(action.tag, subst[0]);
+            } else {
+                token.setState('deleted', true);
+            }
+            continue;
+        }
         token.setState(action.tag, subst);
     }
 }
@@ -57,7 +66,9 @@ const SUBSTITUTIONS = {
     11: singleSubstitutionFormat1,
     12: singleSubstitutionFormat2,
     63: chainingSubstitutionFormat3,
-    41: ligatureSubstitutionFormat1
+    41: ligatureSubstitutionFormat1,
+    51: chainingSubstitutionFormat3,
+    53: chainingSubstitutionFormat3
 };
 
 /**

diff --git a/src/features/ccmp/ccmpReplacementLigatures.js b/src/features/ccmp/ccmpReplacementLigatures.js
@@ -0,0 +1,47 @@
+import { ContextParams } from '../../tokenizer.js';
+import applySubstitution from '../applySubstitution.js';
+
+// @TODO: use commonFeatureUtils.js for reduction of code duplication
+// once #564 has been merged.
+
+/**
+ * Update context params
+ * @param {any} tokens a list of tokens
+ * @param {number} index current item index
+ */
+function getContextParams(tokens, index) {
+    const context = tokens.map(token => token.activeState.value);
+    return new ContextParams(context, index || 0);
+}
+
+/**
+ * Apply ccmp replacement ligatures to a context range
+ * @param {ContextRange} range a range of tokens
+ */
+function ccmpReplacementLigatures(range) {
+    const script = 'delf';
+    const tag = 'ccmp';
+    let tokens = this.tokenizer.getRangeTokens(range);
+    let contextParams = getContextParams(tokens);
+    for(let index = 0; index < contextParams.context.length; index++) {
+        if (!this.query.getFeature({tag, script, contextParams})){
+            continue;
+        }
+        contextParams.setCurrentIndex(index);
+        let substitutions = this.query.lookupFeature({
+            tag, script, contextParams
+        });
+        if (substitutions.length) {
+            for(let i = 0; i < substitutions.length; i++) {
+                const action = substitutions[i];
+                applySubstitution(action, tokens, index);
+            }
+            contextParams = getContextParams(tokens);
+        }
+    }
+}
+
+export default ccmpReplacementLigatures;
+
+
+
diff --git a/src/features/ccmp/contextCheck/ccmpReplacement.js b/src/features/ccmp/contextCheck/ccmpReplacement.js
@@ -0,0 +1,12 @@
+function ccmpReplacementStartCheck(contextParams) {
+    return contextParams.index === 0 && contextParams.context.length > 1;
+}
+
+function ccmpReplacementEndCheck(contextParams) {
+    return contextParams.index === contextParams.context.length - 1;
+}
+
+export default {
+    startCheck: ccmpReplacementStartCheck,
+    endCheck: ccmpReplacementEndCheck
+};
diff --git a/src/features/featureQuery.js b/src/features/featureQuery.js
@@ -203,6 +203,94 @@ function ligatureSubstitutionFormat1(contextParams, subtable) {
     return null;
 }
 
+/**
+ * Handle context substitution - format 1
+ * @param {ContextParams} contextParams context params to lookup
+ */
+function contextSubstitutionFormat1(contextParams, subtable) {
+    let glyphId = contextParams.current;
+    let ligSetIndex = lookupCoverage(glyphId, subtable.coverage);
+    if (ligSetIndex === -1)
+        return null;
+    for (const ruleSet of subtable.ruleSets) {
+        for (const rule of ruleSet) {
+            let matched = true;
+            for (let i = 0; i < rule.input.length; i++) {
+                if (contextParams.lookahead[i] !== rule.input[i]){
+                    matched = false;
+                    break;
+                }
+            }
+            if (matched) {
+                let substitutions = [];
+                substitutions.push(glyphId);
+                for (let i = 0; i < rule.input.length; i++) {
+                    substitutions.push(rule.input[i]);
+                }
+                const parser = (substitutions, lookupRecord)=>{
+                    const {lookupListIndex,sequenceIndex} = lookupRecord;
+                    const {subtables} = this.getLookupByIndex(lookupListIndex);
+                    for (const subtable of subtables){
+                        let ligSetIndex = lookupCoverage(substitutions[sequenceIndex], subtable.coverage);
+                        if (ligSetIndex !== -1){
+                            substitutions[sequenceIndex] = subtable.deltaGlyphId;
+                        }
+                    }
+                };
+
+                for (let i = 0; i < rule.lookupRecords.length; i++) {
+                    const lookupRecord = rule.lookupRecords[i];
+                    parser(substitutions, lookupRecord);
+                }
+
+                return substitutions;
+            }
+        }
+    }
+    return null;
+}
+
+/**
+ * Handle context substitution - format 3
+ * @param {ContextParams} contextParams context params to lookup
+ */
+function contextSubstitutionFormat3(contextParams, subtable) {
+    let substitutions = [];
+
+    for (let i = 0; i < subtable.coverages.length; i++){
+        const lookupRecord = subtable.lookupRecords[i];
+        const coverage = subtable.coverages[i];
+
+        let glyphIndex = contextParams.context[contextParams.index + lookupRecord.sequenceIndex];
+        let ligSetIndex = lookupCoverage(glyphIndex, coverage);
+        if (ligSetIndex === -1){
+            return null;
+        }
+        let lookUp = this.font.tables.gsub.lookups[lookupRecord.lookupListIndex];
+        for (let i = 0; i < lookUp.subtables.length; i++){
+            let subtable = lookUp.subtables[i];
+            let ligSetIndex = lookupCoverage(glyphIndex, subtable.coverage);
+            if (ligSetIndex === -1)
+                return null;
+            switch (lookUp.lookupType) {
+                case 1:{
+                    let ligature = subtable.substitute[ligSetIndex];
+                    substitutions.push(ligature);
+                    break;
+                }
+                case 2:{
+                    let ligatureSet = subtable.sequences[ligSetIndex];
+                    substitutions.push(ligatureSet);
+                    break;
+                } 
+                default:
+                    break;
+            }
+        }
+    }
+    return substitutions;
+}
+
 /**
  * Handle decomposition substitution - format 1
  * @param {number} glyphIndex glyph index
@@ -327,8 +415,17 @@ FeatureQuery.prototype.getLookupMethod = function(lookupTable, subtable) {
             return glyphIndex => decompositionSubstitutionFormat1.apply(
                 this, [glyphIndex, subtable]
             );
+        case '51':
+            return contextParams => contextSubstitutionFormat1.apply(
+                this, [contextParams, subtable]
+            );
+        case '53':
+            return contextParams => contextSubstitutionFormat3.apply(
+                this, [contextParams, subtable]
+            );
         default:
             throw new Error(
+                `substitutionType : ${substitutionType} ` +
                 `lookupType: ${lookupTable.lookupType} - ` +
                 `substFormat: ${subtable.substFormat} ` +
                 'is not yet supported'
@@ -435,6 +532,17 @@ FeatureQuery.prototype.lookupFeature = function (query) {
                         }));
                     }
                     break;
+                case '51':
+                case '53':
+                    substitution = lookup(contextParams);
+                    if (Array.isArray(substitution) && substitution.length) {
+                        substitutions.splice(currentIndex, 1, new SubstitutionAction({
+                            id: parseInt(substType),
+                            tag: query.tag,
+                            substitution
+                        }));
+                    }
+                    break;
             }
             contextParams = new ContextParams(substitutions, currentIndex);
             if (Array.isArray(substitution) && !substitution.length) continue;

diff --git a/test/bidi.js b/test/bidi.js
@@ -143,4 +143,38 @@ describe('bidi.js', function() {
             });
         });
     });
+
+    describe('noto emoji with ccmp', () => {
+        let notoEmojiFont;
+        before(()=> {
+            notoEmojiFont = loadSync('./test/fonts/noto-emoji.ttf');
+        });
+
+        describe('ccmp features', () => {
+
+            it('shape emoji with sub_0', () => {
+                let options = {
+                    kerning: true,
+                    language: 'dflt',
+                    features: [
+                        { script: 'DFLT', tags: ['ccmp'] },
+                    ]
+                };
+                let glyphIndexes = notoEmojiFont.stringToGlyphIndexes('👨‍👩‍👧‍👦👨‍👩‍👧',options);
+                assert.deepEqual(glyphIndexes, [1463,1462]);
+            });
+
+            it('shape emoji with sub_5', () => {
+                let options = {
+                    kerning: true,
+                    language: 'dflt',
+                    features: [
+                        { script: 'DFLT', tags: ['ccmp'] },
+                    ]
+                };
+                let glyphIndexes = notoEmojiFont.stringToGlyphIndexes('🇺🇺',options);
+                assert.deepEqual(glyphIndexes, [1850]);
+            });
+        });
+    });
 });
diff --git a/test/featureQuery.js b/test/featureQuery.js
@@ -9,6 +9,8 @@ describe('featureQuery.js', function() {
     let arabicFont;
     let arabicFontChanga;
     let latinFont;
+    let sub5Font;
+
     let query = {};
     before(function () {
         /**
@@ -23,6 +25,11 @@ describe('featureQuery.js', function() {
          */
         latinFont = loadSync('./test/fonts/FiraSansMedium.woff');
         query.latin = new FeatureQuery(latinFont);
+        /**
+         * default
+         */
+        sub5Font = loadSync('./test/fonts/sub5.ttf');
+        query.sub5 = new FeatureQuery(sub5Font);
     });
     describe('getScriptFeature', function () {
         it('should return features indexes of a given script tag', function () {
@@ -144,6 +151,28 @@ describe('featureQuery.js', function() {
             const substitutions = lookup(contextParams);
             assert.deepEqual(substitutions, { ligGlyph: 1145, components: [76]});
         });
+        it('should parse multiple glyphs -ligature substitution format 1 (51)', function () {
+            const feature = query.sub5.getFeature({tag: 'ccmp', script: 'DFLT'});
+            const featureLookups = query.sub5.getFeatureLookups(feature);
+            const lookupSubtables = query.sub5.getLookupSubtables(featureLookups[0]);
+            const substitutionType = query.sub5.getSubstitutionType(featureLookups[0], lookupSubtables[0]);
+            assert.equal(substitutionType, 51);
+            const lookup = query.sub5.getLookupMethod(featureLookups[0], lookupSubtables[0]);
+            let contextParams = new ContextParams([1, 88, 1], 0);
+            const substitutions = lookup(contextParams);
+            assert.deepEqual(substitutions, [85, 88, 85]);
+        });
+        it('should parse multiple glyphs -ligature substitution format 3 (53)', function () {
+            const feature = query.sub5.getFeature({tag: 'ccmp', script: 'DFLT'});
+            const featureLookups = query.sub5.getFeatureLookups(feature);
+            const lookupSubtables = query.sub5.getLookupSubtables(featureLookups[1]);
+            const substitutionType = query.sub5.getSubstitutionType(featureLookups[1], lookupSubtables[0]);
+            assert.equal(substitutionType, 53);
+            const lookup = query.sub5.getLookupMethod(featureLookups[0], lookupSubtables[0]);
+            let contextParams = new ContextParams([2, 3], 0);
+            const substitutions = lookup(contextParams);
+            assert.deepEqual(substitutions, [54, 54]);
+        });
         it('should decompose a glyph - multiple substitution format 1 (21)', function () {
             const feature = query.arabic.getFeature({tag: 'ccmp', script: 'arab'});
             const featureLookups = query.arabic.getFeatureLookups(feature);

diff --git a/test/fonts/LICENSE b/test/fonts/LICENSE
@@ -26,6 +26,16 @@ Jomhuria-Regular.ttf
     SIL Open Font License, Version 1.1.
     https://www.fontsquirrel.com/license/jomhuria
 
+liga-sub5.ttf
+    Copyright 2024, Tao Qin (https://glyphsapp.com/).
+    SIL Open Font License, Version 1.1.
+    https://opensource.org/licenses/OFL-1.1
+
+noto-emoji.ttf
+    Copyright 2021, Google Inc.
+    SIL Open Font License, version 1.1
+    http://scripts.sil.org/OFL
+
 OpenMojiCOLORv0-subset.ttf
     All emojis designed by OpenMoji – the open-source emoji and icon project.
     Creative Commons Share Alike License 4.0 (CC BY-SA 4.0)
@@ -87,4 +97,4 @@ TestGVAR-Composite-0-Missing.ttf
 Vibur.woff
     Copyright (c) 2010, Johan Kallas (johan.kallas@gmail.com).
     SIL Open Font License, Version 1.1
-    https://www.fontsquirrel.com/license/vibur
+    https://www.fontsquirrel.com/license/vibur
diff --git a/test/fonts/noto-emoji.ttf b/test/fonts/noto-emoji.ttf
diff --git a/test/fonts/sub5.ttf b/test/fonts/sub5.ttf