diff options
Diffstat (limited to 'vcl/source/gdi/impglyphitem.cxx')
| -rw-r--r-- | vcl/source/gdi/impglyphitem.cxx | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/vcl/source/gdi/impglyphitem.cxx b/vcl/source/gdi/impglyphitem.cxx index 300127de6b7a..184e9f819b5a 100644 --- a/vcl/source/gdi/impglyphitem.cxx +++ b/vcl/source/gdi/impglyphitem.cxx @@ -364,6 +364,13 @@ const SalLayoutGlyphs* SalLayoutGlyphsCache::GetLayoutGlyphs( // part being underlined. Doing this for any two segments allows this optimization // even when the prefix of the string would use a different font. // TODO: Can those font differences be ignored? + + // Shaping performance seems to scale poorly with respect to string length. Certain + // writing systems involve extremely long strings (for example, Tibetan: tdf#92064). + // In such cases, this optimization would be a net loss, and must be disabled. + constexpr sal_Int32 nOptLengthThreshold = 20000; + bool bEnableOptimization = (text.getLength() < nOptLengthThreshold); + // Writer layouts tests enable SAL_NON_APPLICATION_FONT_USE=abort in order // to make PrintFontManager::Substitute() abort if font fallback happens. When // laying out the entire string the chance this happens increases (e.g. testAbi11870 @@ -374,7 +381,7 @@ const SalLayoutGlyphs* SalLayoutGlyphsCache::GetLayoutGlyphs( const char* pEnv = getenv("SAL_NON_APPLICATION_FONT_USE"); return pEnv && strcmp(pEnv, "abort") == 0; }(); - if (mLastSubstringKey.has_value() && !bAbortOnFontSubstitute) + if (bEnableOptimization && mLastSubstringKey.has_value() && !bAbortOnFontSubstitute) { sal_Int32 pos = nIndex; if (mLastSubstringKey->len < pos && pos > 0 && text[pos - 1] == nbSpace) |