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Fix kerning errors when using DirectWrite backend 

There were a couple of errors when calculating advances
in the DirectWrite font engine: First of all, we would
apply the CLEARTYPE_NATURAL glyph metrics when using
GDI_CLASSIC rendering, causing text to look compressed
in some places, because we always passed TRUE for the
useGdiNatural parameter to GetGdiCompatibleGlyphMetrics().

In addition, we would pick the GDI-compatible metrics even
when design metrics had explicitly been requested on the
layout. This is the case for distance field rendered text,
which always operates with design metrics and scalable
layouts, so it was visible as kerning errors on some text
there.

Fixes: QTBUG-122139
Fixes: QTBUG-122167
Change-Id: Ic28da6b3235d7af0452bdcb836e037594f8a20ba
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
(cherry picked from commit de3d5dd73b)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 90963387e4)
(cherry picked from commit 1d244eb910)
This commit is contained in:
Eskil Abrahamsen Blomfeldt 2024-02-13 13:24:15 +01:00 committed by Qt Cherry-pick Bot
parent 2880f8b2f6
commit 875f8a795f
1 changed files with 5 additions and 3 deletions
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8
src/gui/text/windows/qwindowsfontenginedirectwrite.cpp
View File

@ -466,7 +466,7 @@ QFontEngine::FaceId QWindowsFontEngineDirectWrite::faceId() const
return m_faceId;
}
void QWindowsFontEngineDirectWrite::recalcAdvances(QGlyphLayout *glyphs, QFontEngine::ShaperFlags) const
void QWindowsFontEngineDirectWrite::recalcAdvances(QGlyphLayout *glyphs, QFontEngine::ShaperFlags shaperFlags) const
{
QVarLengthArray<UINT16> glyphIndices(glyphs->numGlyphs);
@ -478,11 +478,13 @@ void QWindowsFontEngineDirectWrite::recalcAdvances(QGlyphLayout *glyphs, QFontEn
HRESULT hr;
DWRITE_RENDERING_MODE renderMode = hintingPreferenceToRenderingMode(fontDef);
if (renderMode == DWRITE_RENDERING_MODE_GDI_CLASSIC || renderMode == DWRITE_RENDERING_MODE_GDI_NATURAL) {
bool needsDesignMetrics = shaperFlags & QFontEngine::DesignMetrics;
if (!needsDesignMetrics && (renderMode == DWRITE_RENDERING_MODE_GDI_CLASSIC
|| renderMode == DWRITE_RENDERING_MODE_GDI_NATURAL)) {
hr = m_directWriteFontFace->GetGdiCompatibleGlyphMetrics(float(fontDef.pixelSize),
1.0f,
NULL,
TRUE,
renderMode == DWRITE_RENDERING_MODE_GDI_NATURAL,
glyphIndices.data(),
glyphIndices.size(),
glyphMetrics.data());