From ce2ae6ebd8cfebf9edbb0b5653e80de029669548 Mon Sep 17 00:00:00 2001 From: Eskil Abrahamsen Blomfeldt Date: Mon, 17 Oct 2016 13:35:45 +0200 Subject: [PATCH] Windows: Fix rendering of MingLiU fonts at some scales At certain sizes and scales, GDI will clip away the bottom line of pixels when rendering the MingLiU fonts. Since DirectWrite renders it correctly, we force the use of DirectWrite in this case. This also requires supporting classic GDI rendering in the DirectWrite engine, to make sure the rendering still looks correct. Note that this does not cover the corner case where the font is loaded directly from data with QRawFont. [ChangeLog][QtGui][Windows] Fixed rendering error when using the MingLiU fonts at certain combinations of pixel size and scale. Task-number: QTBUG-49346 Change-Id: Ie026c0d5932717858c4536dae077013eb6a1eafc Reviewed-by: Konstantin Ritt Reviewed-by: Simon Hausmann --- .../windows/qwindowsfontdatabase.cpp | 12 +++++++++-- .../windows/qwindowsfontenginedirectwrite.cpp | 20 +++++++++++++------ 2 files changed, 24 insertions(+), 8 deletions(-) diff --git a/src/plugins/platforms/windows/qwindowsfontdatabase.cpp b/src/plugins/platforms/windows/qwindowsfontdatabase.cpp index 4f022141cf..1630b80306 100644 --- a/src/plugins/platforms/windows/qwindowsfontdatabase.cpp +++ b/src/plugins/platforms/windows/qwindowsfontdatabase.cpp @@ -110,13 +110,21 @@ static void createDirectWriteFactory(IDWriteFactory **factory) *factory = static_cast(result); } -static inline bool useDirectWrite(QFont::HintingPreference hintingPreference, bool isColorFont = false) +static inline bool useDirectWrite(QFont::HintingPreference hintingPreference, + const QString &familyName = QString(), + bool isColorFont = false) { const unsigned options = QWindowsIntegration::instance()->options(); if (Q_UNLIKELY(options & QWindowsIntegration::DontUseDirectWriteFonts)) return false; if (isColorFont) return (options & QWindowsIntegration::DontUseColorFonts) == 0; + + // At some scales, GDI will misrender the MingLiU font, so we force use of + // DirectWrite to work around the issue. + if (Q_UNLIKELY(familyName.startsWith(QLatin1String("MingLiU")))) + return true; + return hintingPreference == QFont::PreferNoHinting || hintingPreference == QFont::PreferVerticalHinting || (QHighDpiScaling::isActive() && hintingPreference == QFont::PreferDefaultHinting); @@ -1875,7 +1883,7 @@ QFontEngine *QWindowsFontDatabase::createEngine(const QFontDef &request, #endif const QFont::HintingPreference hintingPreference = static_cast(request.hintingPreference); - const bool useDw = useDirectWrite(hintingPreference, isColorFont); + const bool useDw = useDirectWrite(hintingPreference, fam, isColorFont); qCDebug(lcQpaFonts) << __FUNCTION__ << request.family << request.pointSize << "pt" << "hintingPreference=" << hintingPreference << "color=" << isColorFont << dpi << "dpi" << "useDirectWrite=" << useDw; diff --git a/src/plugins/platforms/windows/qwindowsfontenginedirectwrite.cpp b/src/plugins/platforms/windows/qwindowsfontenginedirectwrite.cpp index 66cc08f9fa..334e9cb8b9 100644 --- a/src/plugins/platforms/windows/qwindowsfontenginedirectwrite.cpp +++ b/src/plugins/platforms/windows/qwindowsfontenginedirectwrite.cpp @@ -185,6 +185,18 @@ namespace { } +static DWRITE_RENDERING_MODE hintingPreferenceToRenderingMode(QFont::HintingPreference hintingPreference) +{ + switch (hintingPreference) { + case QFont::PreferNoHinting: + return DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC; + case QFont::PreferVerticalHinting: + return DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL; + default: + return DWRITE_RENDERING_MODE_CLEARTYPE_GDI_CLASSIC; + } +} + /*! \class QWindowsFontEngineDirectWrite \brief Windows font engine using Direct Write. @@ -661,9 +673,7 @@ QImage QWindowsFontEngineDirectWrite::imageForGlyph(glyph_t t, transform.m22 = xform.m22(); DWRITE_RENDERING_MODE renderMode = - fontDef.hintingPreference == QFont::PreferNoHinting - ? DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC - : DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL; + hintingPreferenceToRenderingMode(QFont::HintingPreference(fontDef.hintingPreference)); IDWriteGlyphRunAnalysis *glyphAnalysis = NULL; HRESULT hr = m_fontEngineData->directWriteFactory->CreateGlyphRunAnalysis( @@ -950,9 +960,7 @@ glyph_metrics_t QWindowsFontEngineDirectWrite::alphaMapBoundingBox(glyph_t glyph transform.m22 = matrix.m22(); DWRITE_RENDERING_MODE renderMode = - fontDef.hintingPreference == QFont::PreferNoHinting - ? DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC - : DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL; + hintingPreferenceToRenderingMode(QFont::HintingPreference(fontDef.hintingPreference)); IDWriteGlyphRunAnalysis *glyphAnalysis = NULL; HRESULT hr = m_fontEngineData->directWriteFactory->CreateGlyphRunAnalysis(