Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6141db38 authored by Raph Levien's avatar Raph Levien
Browse files

Don't count zero width space in hasGlyph layout 

For sequences that may form ligatures (ie not just a a base
character plus variation selector pair), hasGlyph requests a layout
and then counts the glyph. In some cases, when the source string
contains a variation selector, the layout contains space glyphs with
no associated width, which causes a "false" result. This patch
filters out such zero width spaces.

Bug: 30056285
Change-Id: I9b5db4aa5ad24bf43e237c98b610fd269f2b91c9
parent 807cf869

core/jni/android/graphics/Paint.cpp

+16 −1
Original line number Diff line number Diff line
@@ -769,6 +769,21 @@ namespace PaintGlue { 
        return false;

    }



    // Don't count glyphs that are the recommended "space" glyph and are zero width.

    // This logic makes assumptions about HarfBuzz layout, but does correctly handle

    // cases where ligatures form and zero width space glyphs are left in as

    // placeholders.

    static size_t countNonSpaceGlyphs(const minikin::Layout& layout) {

        size_t count = 0;

        static unsigned int kSpaceGlyphId = 3;

        for (size_t i = 0; i < layout.nGlyphs(); i++) {

            if (layout.getGlyphId(i) != kSpaceGlyphId || layout.getCharAdvance(i) != 0.0) {

                count++;

            }

        }

        return count;

    }



    // Returns true if the given string is exact one pair of regional indicators.

    static bool isFlag(const jchar* str, size_t length) {

        const jchar RI_LEAD_SURROGATE = 0xD83C;
@@ -832,7 +847,7 @@ namespace PaintGlue { 
        minikin::Layout layout;

        MinikinUtils::doLayout(&layout, paint, bidiFlags, typeface, str.get(), 0, str.size(),

                str.size());

        size_t nGlyphs = layout.nGlyphs();

        size_t nGlyphs = countNonSpaceGlyphs(layout);

        if (nGlyphs != 1 && nChars > 1) {

            // multiple-character input, and was not a ligature

            // TODO: handle ZWJ/ZWNJ characters specially so we can detect certain ligatures