554 latin rlig

docs/index.html

@@ -114,7 +114,7 @@ <h1>Free Software</h1>
         hinting: form.hinting.checked,
         features: {
             liga: form.ligatures.checked,
-            rlig: form.ligatures.checked
+            rlig: true
         }
     };
     previewCtx.clearRect(0, 0, 940, 300);

src/bidi.js

@@ -10,7 +10,7 @@ import arabicSentenceCheck from './features/arab/contextCheck/arabicSentence.js'
 import arabicPresentationForms from './features/arab/arabicPresentationForms.js';
 import arabicRequiredLigatures from './features/arab/arabicRequiredLigatures.js';
 import latinWordCheck from './features/latn/contextCheck/latinWord.js';
-import latinLigature from './features/latn/latinLigatures.js';
+import { latinRequiredLigature, latinLigature } from './features/latn/latinLigatures.js';
 import thaiWordCheck from './features/thai/contextCheck/thaiWord.js';
 import unicodeVariationSequenceCheck from './features/unicode/contextCheck/variationSequenceCheck.js';
 import unicodeVariationSequences from './features/unicode/variationSequences.js';
@@ -281,15 +281,26 @@ function applyArabicRequireLigatures() {
 }
 
 /**
- * Apply required arabic ligatures
+ * Apply required and normal latin ligatures
  */
 function applyLatinLigatures() {
-    if (!this.hasFeatureEnabled('latn', 'liga')) return;
+    const script = 'latn';
+    if (!Object.prototype.hasOwnProperty.call(this.featuresTags, script)) return;
+    const tags = this.featuresTags[script];
+    if ((tags.indexOf('rlig') === -1) && (tags.indexOf('liga') === -1)) return;
     checkGlyphIndexStatus.call(this);
     const ranges = this.tokenizer.getContextRanges('latinWord');
+
     for(let i = 0; i < ranges.length; i++) {
         const range = ranges[i];
-        latinLigature.call(this, range);
+
+        if (tags.indexOf('rlig') >= 0) {
+            latinRequiredLigature.call(this, range);
+        }
+
+        if (tags.indexOf('liga') >= 0) {
+            latinLigature.call(this, range);
+        }
     }
 }
 

src/features/arab/arabicRequiredLigatures.js

@@ -2,43 +2,14 @@
  * Apply Arabic required ligatures feature to a range of tokens
  */
 
-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);
-}
+import { applyFeatureToRange } from '../commonFeatureUtils.js';
 
 /**
  * Apply Arabic required ligatures to a context range
  * @param {ContextRange} range a range of tokens
  */
 function arabicRequiredLigatures(range) {
-    const script = 'arab';
-    let tokens = this.tokenizer.getRangeTokens(range);
-    let contextParams = getContextParams(tokens);
-    for (let index = 0; index < contextParams.context.length; index++) {
-        contextParams.setCurrentIndex(index);
-        let substitutions = this.query.lookupFeature({
-            tag: 'rlig', script, contextParams
-        });
-        if (substitutions.length) {
-            for(let i = 0; i < substitutions.length; i++) {
-                const action = substitutions[i];
-                applySubstitution.call(this, action, tokens, index);
-            }
-            contextParams = getContextParams(tokens);
-        }
-    }
+    applyFeatureToRange.apply(this, ['arab', 'rlig', range]);
 }
 
 export default arabicRequiredLigatures;

src/features/commonFeatureUtils.js

@@ -0,0 +1,38 @@
+import { ContextParams } from '../tokenizer.js';
+import applySubstitution from './applySubstitution.js';
+
+/**
+ * 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 feature substitutions to a context range
+ * @param {string} script a script tag
+ * @param {string} feature 4-letter feature code
+ * @param {ContextRange} range a range of tokens
+ */
+function applyFeatureToRange(script, feature, range) {
+    let tokens = this.tokenizer.getRangeTokens(range);
+    let contextParams = getContextParams(tokens);
+    for (let index = 0; index < contextParams.context.length; index++) {
+        contextParams.setCurrentIndex(index);
+        let substitutions = this.query.lookupFeature({
+            tag: feature, 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 { getContextParams, applyFeatureToRange };

src/features/latn/latinLigatures.js

@@ -2,43 +2,23 @@
  * Apply Latin ligature feature to a range of tokens
  */
 
-import { ContextParams } from '../../tokenizer.js';
-import applySubstitution from '../applySubstitution.js';
-
-// @TODO: use commonFeatureUtils.js for reduction of code duplication
-// once #564 has been merged.
+import { applyFeatureToRange } from '../commonFeatureUtils.js';
 
 /**
- * Update context params
- * @param {any} tokens a list of tokens
- * @param {number} index current item index
+ * Apply Latin required ligatures to a context range
+ * @param {ContextRange} range a range of tokens
  */
-function getContextParams(tokens, index) {
-    const context = tokens.map(token => token.activeState.value);
-    return new ContextParams(context, index || 0);
+function latinRequiredLigature(range) {
+    applyFeatureToRange.apply(this, ['latn', 'rlig', range]);
 }
 
 /**
- * Apply Arabic required ligatures to a context range
+ * Apply Latin ligatures to a context range
  * @param {ContextRange} range a range of tokens
  */
 function latinLigature(range) {
-    const script = 'latn';
-    let tokens = this.tokenizer.getRangeTokens(range);
-    let contextParams = getContextParams(tokens);
-    for(let index = 0; index < contextParams.context.length; index++) {
-        contextParams.setCurrentIndex(index);
-        let substitutions = this.query.lookupFeature({
-            tag: 'liga', script, contextParams
-        });
-        if (substitutions.length) {
-            for(let i = 0; i < substitutions.length; i++) {
-                const action = substitutions[i];
-                applySubstitution.call(this, action, tokens, index);
-            }
-            contextParams = getContextParams(tokens);
-        }
-    }
+    applyFeatureToRange.apply(this, ['latn', 'liga', range]);
 }
 
 export default latinLigature;
+export { latinRequiredLigature, latinLigature };

test/bidi.js

@@ -7,8 +7,11 @@ const loadSync = (url, opt) => parse(readFileSync(url), opt);
 describe('bidi.js', function() {
     let latinFont;
     let arabicFont;
+    let scriptFont;
     let bidiFira;
     let bidiScheherazade;
+    let bidiPecita;
+    let bidiPecitaNoRlig;
     let arabicTokenizer;
 
     before(function () {
@@ -40,6 +43,28 @@ describe('bidi.js', function() {
             tags: ['liga', 'rlig']
         }];
         bidiFira.applyFeatures(latinFont, latinFeatures);
+        /**
+         * script font for rlig tests
+         */
+        scriptFont = loadSync('./test/fonts/Pecita.ttf');
+        bidiPecita = new Bidi();
+        bidiPecita.registerModifier(
+            'glyphIndex', null, token => scriptFont.charToGlyphIndex(token.char)
+            );
+        bidiPecitaNoRlig = new Bidi();
+        bidiPecitaNoRlig.registerModifier(
+            'glyphIndex', null, token => scriptFont.charToGlyphIndex(token.char)
+        );
+        const scriptFeatures = [{
+            script: 'latn',
+            tags: ['liga', 'rlig']
+        }];
+        const scriptFeaturesNoRlig = [{
+            script: 'latn',
+            tags: ['liga']
+        }];
+        bidiPecita.applyFeatures(scriptFont, scriptFeatures);
+        bidiPecitaNoRlig.applyFeatures(scriptFont, scriptFeaturesNoRlig);
     });
     describe('arabic contexts', function() {
         it('should match arabic words in a given text', function() {
@@ -83,6 +108,14 @@ describe('bidi.js', function() {
             let glyphIndexes = bidiScheherazade.getTextGlyphs('َّ'); // Arabic word 'َّ' : 'Fatha & Shadda'
             assert.deepEqual(glyphIndexes, [1311]);
         });
+        it('should apply required latin ligature', function () {
+            let glyphIndexes = bidiPecita.getTextGlyphs('quick');
+            assert.deepEqual(glyphIndexes, [4130, 79, 3676]); // "qu" and "ck" rlig
+        });
+        it('should render differently without required latin ligatures', function () {
+            let glyphIndexes = bidiPecitaNoRlig.getTextGlyphs('quick'); // no rligs
+            assert.deepEqual(glyphIndexes, [87, 91, 79, 73, 81]);
+        });
         it('should apply latin ligature', function () {
             let glyphIndexes = bidiFira.getTextGlyphs('fi'); // fi => fi
             assert.deepEqual(glyphIndexes, [1145]);