Disable letter-spacing for Arabic text (issue mapbox#4208)

IvanSanchez · May 19, 2017 · a1f4938 · a1f4938
1 parent 18f7c51
commit a1f4938
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Showing 5 changed files with 86 additions and 9 deletions.
diff --git a/src/data/bucket/symbol_bucket.js b/src/data/bucket/symbol_bucket.js
@@ -360,10 +360,11 @@ class SymbolBucket {
             if (feature.text) {
                 const allowsVerticalWritingMode = scriptDetection.allowsVerticalWritingMode(feature.text);
                 const textOffset = this.layers[0].getLayoutValue('text-offset', {zoom: this.zoom}, feature.properties).map((t)=> t * oneEm);
+                const spacingIfAllowed = scriptDetection.allowsLetterSpacing(feature.text) ? spacing : 0;
 
                 shapedTextOrientations = {
-                    [WritingMode.horizontal]: shapeText(feature.text, stacks[fontstack], maxWidth, lineHeight, horizontalAlign, verticalAlign, justify, spacing, textOffset, oneEm, WritingMode.horizontal),
-                    [WritingMode.vertical]: allowsVerticalWritingMode && textAlongLine && shapeText(feature.text, stacks[fontstack], maxWidth, lineHeight, horizontalAlign, verticalAlign, justify, spacing, textOffset, oneEm, WritingMode.vertical)
+                    [WritingMode.horizontal]: shapeText(feature.text, stacks[fontstack], maxWidth, lineHeight, horizontalAlign, verticalAlign, justify, spacingIfAllowed, textOffset, oneEm, WritingMode.horizontal),
+                    [WritingMode.vertical]: allowsVerticalWritingMode && textAlongLine && shapeText(feature.text, stacks[fontstack], maxWidth, lineHeight, horizontalAlign, verticalAlign, justify, spacingIfAllowed, textOffset, oneEm, WritingMode.vertical)
                 };
             } else {
                 shapedTextOrientations = {};

diff --git a/src/util/is_char_in_unicode_block.js b/src/util/is_char_in_unicode_block.js
@@ -18,15 +18,15 @@ const unicodeBlockLookup: UnicodeBlockLookup = {
     // 'Cyrillic': (char) => char >= 0x0400 && char <= 0x04FF,
     // 'Cyrillic Supplement': (char) => char >= 0x0500 && char <= 0x052F,
     // 'Armenian': (char) => char >= 0x0530 && char <= 0x058F,
-    // 'Hebrew': (char) => char >= 0x0590 && char <= 0x05FF,
-    // 'Arabic': (char) => char >= 0x0600 && char <= 0x06FF,
-    // 'Syriac': (char) => char >= 0x0700 && char <= 0x074F,
-    // 'Arabic Supplement': (char) => char >= 0x0750 && char <= 0x077F,
+    //'Hebrew': (char) => char >= 0x0590 && char <= 0x05FF,
+    'Arabic': (char) => char >= 0x0600 && char <= 0x06FF,
+    //'Syriac': (char) => char >= 0x0700 && char <= 0x074F,
+    'Arabic Supplement': (char) => char >= 0x0750 && char <= 0x077F,
     // 'Thaana': (char) => char >= 0x0780 && char <= 0x07BF,
     // 'NKo': (char) => char >= 0x07C0 && char <= 0x07FF,
     // 'Samaritan': (char) => char >= 0x0800 && char <= 0x083F,
     // 'Mandaic': (char) => char >= 0x0840 && char <= 0x085F,
-    // 'Arabic Extended-A': (char) => char >= 0x08A0 && char <= 0x08FF,
+    'Arabic Extended-A': (char) => char >= 0x08A0 && char <= 0x08FF,
     // 'Devanagari': (char) => char >= 0x0900 && char <= 0x097F,
     // 'Bengali': (char) => char >= 0x0980 && char <= 0x09FF,
     // 'Gurmukhi': (char) => char >= 0x0A00 && char <= 0x0A7F,
@@ -159,13 +159,13 @@ const unicodeBlockLookup: UnicodeBlockLookup = {
     'Private Use Area': (char) => char >= 0xE000 && char <= 0xF8FF,
     'CJK Compatibility Ideographs': (char) => char >= 0xF900 && char <= 0xFAFF,
     // 'Alphabetic Presentation Forms': (char) => char >= 0xFB00 && char <= 0xFB4F,
-    // 'Arabic Presentation Forms-A': (char) => char >= 0xFB50 && char <= 0xFDFF,
+    'Arabic Presentation Forms-A': (char) => char >= 0xFB50 && char <= 0xFDFF,
     // 'Variation Selectors': (char) => char >= 0xFE00 && char <= 0xFE0F,
     'Vertical Forms': (char) => char >= 0xFE10 && char <= 0xFE1F,
     // 'Combining Half Marks': (char) => char >= 0xFE20 && char <= 0xFE2F,
     'CJK Compatibility Forms': (char) => char >= 0xFE30 && char <= 0xFE4F,
     'Small Form Variants': (char) => char >= 0xFE50 && char <= 0xFE6F,
-    // 'Arabic Presentation Forms-B': (char) => char >= 0xFE70 && char <= 0xFEFF,
+    'Arabic Presentation Forms-B': (char) => char >= 0xFE70 && char <= 0xFEFF,
     'Halfwidth and Fullwidth Forms': (char) => char >= 0xFF00 && char <= 0xFFEF
     // 'Specials': (char) => char >= 0xFFF0 && char <= 0xFFFF,
     // 'Linear B Syllabary': (char) => char >= 0x10000 && char <= 0x1007F,

diff --git a/src/util/script_detection.js b/src/util/script_detection.js
@@ -17,6 +17,23 @@ module.exports.allowsVerticalWritingMode = function(chars) {
     return false;
 };
 
+module.exports.allowsLetterSpacing = function(chars) {
+    for (const char of chars) {
+        if (!exports.charAllowsLetterSpacing(char.charCodeAt(0))) return false;
+    }
+    return true;
+};
+
+module.exports.charAllowsLetterSpacing = function(char) {
+    if (isChar['Arabic'](char)) return false;
+    if (isChar['Arabic Supplement'](char)) return false;
+    if (isChar['Arabic Extended-A'](char)) return false;
+    if (isChar['Arabic Presentation Forms-A'](char)) return false;
+    if (isChar['Arabic Presentation Forms-B'](char)) return false;
+
+    return true;
+};
+
 module.exports.charAllowsIdeographicBreaking = function(char) {
     // Return early for characters outside all ideographic ranges.
     if (char < 0x2E80) return false;

diff --git a/test/integration/render-tests/text-arabic/letter-spacing/expected.png b/test/integration/render-tests/text-arabic/letter-spacing/expected.png
diff --git a/test/integration/render-tests/text-arabic/letter-spacing/style.json b/test/integration/render-tests/text-arabic/letter-spacing/style.json
@@ -0,0 +1,59 @@
+{
+    "version": 8,
+    "metadata": {
+        "test": {
+            "ignored": {
+              "native": "https://github.com/mapbox/mapbox-gl-native/issues/9057"
+            },
+            "width": 256,
+            "height": 256
+        }
+    },
+    "sources": {
+        "geojson": {
+            "type": "geojson",
+            "data": {
+                "type": "FeatureCollection",
+                "features": [
+                    {
+                        "type": "Feature",
+                        "properties": { "name": "مجتمع آپارتمانهای مرتفع Not spaced" },
+                        "geometry": {
+                            "type": "Point",
+                            "coordinates": [ 0, 0 ]
+                        }
+                    },
+                    {
+                        "type": "Feature",
+                        "properties": { "name": "Spaced" },
+                        "geometry": {
+                            "type": "Point",
+                            "coordinates": [ 0, 30 ]
+                        }
+                    }
+                ]
+            }
+        }
+    },
+    "glyphs": "local://glyphs/{fontstack}/{range}.pbf",
+    "layers": [
+        {
+            "id": "symbol",
+            "type": "symbol",
+            "source": "geojson",
+            "layout": {
+                "symbol-placement": "point",
+                "symbol-spacing": 20,
+                "text-allow-overlap": true,
+                "text-letter-spacing": 1,
+                "text-rotation-alignment": "auto",
+                "text-max-width": 5,
+                "text-field": "{name}",
+                "text-font": [
+                    "Open Sans Semibold",
+                    "Arial Unicode MS Bold"
+                ]
+            }
+        }
+    ]
+}