Merge "Suppress grapheme cluster breaks in emoji with modifiers" into nyc-dev

libs/minikin/GraphemeBreak.cpp

@@ -77,6 +77,48 @@ bool isZwjEmoji(uint32_t c) {
             || c == 0x1F5E8); // LEFT SPEECH BUBBLE
 }
 
+// Based on Modifiers from http://www.unicode.org/L2/L2016/16011-data-file.txt
+bool isEmojiModifier(uint32_t c) {
+    return (0x1F3FB <= c && c <= 0x1F3FF);
+}
+
+// Based on Emoji_Modifier_Base from
+// http://www.unicode.org/Public/emoji/3.0/emoji-data.txt
+bool isEmojiBase(uint32_t c) {
+    if (0x261D <= c && c <= 0x270D) {
+        return (c == 0x261D || c == 0x26F9 || (0x270A <= c && c <= 0x270D));
+    } else if (0x1F385 <= c && c <= 0x1F93E) {
+        return (c == 0x1F385
+                || (0x1F3C3 <= c || c <= 0x1F3C4)
+                || (0x1F3CA <= c || c <= 0x1F3CB)
+                || (0x1F442 <= c || c <= 0x1F443)
+                || (0x1F446 <= c || c <= 0x1F450)
+                || (0x1F466 <= c || c <= 0x1F469)
+                || c == 0x1F46E
+                || (0x1F470 <= c || c <= 0x1F478)
+                || c == 0x1F47C
+                || (0x1F481 <= c || c <= 0x1F483)
+                || (0x1F485 <= c || c <= 0x1F487)
+                || c == 0x1F4AA
+                || c == 0x1F575
+                || c == 0x1F57A
+                || c == 0x1F590
+                || (0x1F595 <= c || c <= 0x1F596)
+                || (0x1F645 <= c || c <= 0x1F647)
+                || (0x1F64B <= c || c <= 0x1F64F)
+                || c == 0x1F6A3
+                || (0x1F6B4 <= c || c <= 0x1F6B6)
+                || c == 0x1F6C0
+                || (0x1F918 <= c || c <= 0x1F91E)
+                || c == 0x1F926
+                || c == 0x1F930
+                || (0x1F933 <= c || c <= 0x1F939)
+                || (0x1F93B <= c || c <= 0x1F93E));
+    } else {
+        return false;
+    }
+}
+
 bool GraphemeBreak::isGraphemeBreak(const uint16_t* buf, size_t start, size_t count,
         size_t offset) {
     // This implementation closely follows Unicode Standard Annex #29 on
@@ -165,6 +207,17 @@ bool GraphemeBreak::isGraphemeBreak(const uint16_t* buf, size_t start, size_t co
             return false;
         }
     }
+    // Proposed Rule GB9c from http://www.unicode.org/L2/L2016/16011r3-break-prop-emoji.pdf
+    // E_Base x E_Modifier
+    if (isEmojiModifier(c2)) {
+        if (c1 == 0xFE0F && offset_back > start) {
+            // skip over emoji variation selector
+            U16_PREV(buf, start, offset_back, c1);
+        }
+        if (isEmojiBase(c1)) {
+            return false;
+        }
+    }
     // Rule GB10, Any ÷ Any
     return true;
 }

tests/GraphemeBreakTests.cpp

@@ -136,6 +136,30 @@ TEST(GraphemeBreak, tailoring) {
     EXPECT_TRUE(IsBreak("U+0628 U+200D | U+2764"));
 }
 
+TEST(GraphemeBreak, emojiModifiers) {
+    EXPECT_FALSE(IsBreak("U+261D | U+1F3FB"));  // white up pointing index + modifier
+    EXPECT_FALSE(IsBreak("U+270C | U+1F3FB"));  // victory hand + modifier
+    EXPECT_FALSE(IsBreak("U+1F466 | U+1F3FB"));  // boy + modifier
+    EXPECT_FALSE(IsBreak("U+1F466 | U+1F3FC"));  // boy + modifier
+    EXPECT_FALSE(IsBreak("U+1F466 | U+1F3FD"));  // boy + modifier
+    EXPECT_FALSE(IsBreak("U+1F466 | U+1F3FE"));  // boy + modifier
+    EXPECT_FALSE(IsBreak("U+1F466 | U+1F3FF"));  // boy + modifier
+    EXPECT_FALSE(IsBreak("U+1F918 | U+1F3FF"));  // sign of the horns + modifier
+    EXPECT_FALSE(IsBreak("U+1F933 | U+1F3FF"));  // selfie (Unicode 9) + modifier
+
+    // adding emoji style variation selector doesn't affect grapheme cluster
+    EXPECT_TRUE(IsBreak("U+270C U+FE0E | U+1F3FB"));  // victory hand + text style + modifier
+    EXPECT_FALSE(IsBreak("U+270C U+FE0F | U+1F3FB"));  // heart + emoji style + modifier
+
+    // heart is not an emoji base
+    EXPECT_TRUE(IsBreak("U+2764 | U+1F3FB"));  // heart + modifier
+    EXPECT_TRUE(IsBreak("U+2764 U+FE0E | U+1F3FB"));  // heart + emoji style + modifier
+    EXPECT_TRUE(IsBreak("U+2764 U+FE0F | U+1F3FB"));  // heart + emoji style + modifier
+
+    // rat is not an emoji modifer
+    EXPECT_TRUE(IsBreak("U+1F466 | U+1F400"));  // boy + rat
+}
+
 TEST(GraphemeBreak, offsets) {
     uint16_t string[] = { 0x0041, 0x06DD, 0x0045, 0x0301, 0x0049, 0x0301 };
     EXPECT_TRUE(GraphemeBreak::isGraphemeBreak(string, 2, 3, 2));