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Tailor grapheme boundaries so sequence emoji are one grapheme - DO NOT MERGE

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Make it so it's not possible to position the cursor inside an emoji
formed by a sequence including zero-width joiners.

Bug: 25368653
Change-Id: I67ec0874cd1505f3c82ab91492ffc3d39a52fae6
This commit is contained in:
Raph Levien 2015-10-29 14:06:07 -07:00
parent 8921cfe226
commit 2e98eb6be1
1 changed files with 26 additions and 0 deletions
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26
libs/minikin/GraphemeBreak.cpp
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@ -22,6 +22,19 @@
namespace android {
// Returns true if the character appears before or after zwj in a zwj emoji sequence. See
// http://www.unicode.org/emoji/charts/emoji-zwj-sequences.html
bool isZwjEmoji(uint32_t c) {
return (c == 0x2764 // HEAVY BLACK HEART
|| c == 0x1F468 // MAN
|| c == 0x1F469 // WOMAN
|| c == 0x1F48B // KISS MARK
|| c == 0x1F466 // BOY
|| c == 0x1F467 // GIRL
|| c == 0x1F441 // EYE
|| c == 0x1F5E8); // LEFT SPEECH BUBBLE
}
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
@ -93,6 +106,19 @@ bool GraphemeBreak::isGraphemeBreak(const uint16_t* buf, size_t start, size_t co
&& u_getIntPropertyValue(c2, UCHAR_GENERAL_CATEGORY) == U_OTHER_LETTER) {
return false;
}
// Tailoring: make emoji sequences with ZWJ a single grapheme cluster
if (c1 == 0x200D && isZwjEmoji(c2) && offset_back > start) {
// look at character before ZWJ to see that both can participate in an emoji zwj sequence
uint32_t c0 = 0;
U16_PREV(buf, start, offset_back, c0);
if (c0 == 0xFE0F && offset_back > start) {
// skip over emoji variation selector
U16_PREV(buf, start, offset_back, c0);
}
if (isZwjEmoji(c0)) {
return false;
}
}
// Rule GB10, Any / Any
return true;
}