tdf#104159: Re-enable OpenGL glyph caching on Windows

Change-Id: Icafec05a8cf4428d806efcb286addf3042fcf021
Reviewed-on: https://gerrit.libreoffice.org/32026Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Khaled Hosny <khaledhosny@eglug.org>

vcl/inc/CommonSalLayout.hxx

@@ -45,6 +45,7 @@ class CommonSalLayout : public GenericSalLayout
 #ifdef _WIN32
     HDC                     mhDC;
     HFONT                   mhFont;
+    WinFontInstance&        mrWinFontInstance;
     double                  mnAveWidthFactor;
 #elif defined(MACOSX) || defined(IOS)
     const CoreTextStyle&    mrCoreTextStyle;
@@ -67,6 +68,8 @@ public:
 #if defined(_WIN32)
     explicit                CommonSalLayout(HDC, WinFontInstance&, const WinFontFace&);
     const FontSelectPattern& getFontSelData() const { return mrFontSelData; };
+    HFONT                   getHFONT() const { return mhFont; }
+    WinFontInstance&        getWinFontInstance() const { return mrWinFontInstance; }
 #elif defined(MACOSX) || defined(IOS)
     explicit                CommonSalLayout(const CoreTextStyle&);
     const CoreTextStyle&    getFontData() const { return mrCoreTextStyle; };

vcl/inc/win/salgdi.h

@@ -180,6 +180,9 @@ private:
 
     LogicalFontInstance* GetWinFontEntry(int nFallbackLevel);
 
+    bool CacheGlyphs(const CommonSalLayout& rLayout);
+    bool DrawCachedGlyphs(const CommonSalLayout& rLayout);
+
 public:
     HDC getHDC() const { return mhLocalDC; }
     void setHDC(HDC aNew) { mhLocalDC = aNew; }

vcl/source/gdi/CommonSalLayout.cxx

@@ -181,6 +181,7 @@ CommonSalLayout::CommonSalLayout(HDC hDC, WinFontInstance& rWinFontInstance, con
 :   mrFontSelData(rWinFontInstance.maFontSelData)
 ,   mhDC(hDC)
 ,   mhFont(static_cast<HFONT>(GetCurrentObject(hDC, OBJ_FONT)))
+,   mrWinFontInstance(rWinFontInstance)
 ,   mnAveWidthFactor(1.0f)
 ,   mpVertGlyphs(nullptr)
 {

vcl/win/gdi/winlayout.cxx

@@ -666,6 +666,70 @@ LogicalFontInstance* WinFontFace::CreateFontInstance( FontSelectPattern& rFSD )
     return pFontInstance;
 }
 
+bool WinSalGraphics::CacheGlyphs(const CommonSalLayout& rLayout)
+{
+    static bool bDoGlyphCaching = (std::getenv("SAL_DISABLE_GLYPH_CACHING") == nullptr);
+    if (!bDoGlyphCaching)
+        return false;
+
+    HDC hDC = getHDC();
+    HFONT hFONT = rLayout.getHFONT();
+    WinFontInstance& rFont = rLayout.getWinFontInstance();
+
+    int nStart = 0;
+    Point aPos(0, 0);
+    const GlyphItem* pGlyph;
+    while (rLayout.GetNextGlyphs(1, &pGlyph, aPos, nStart))
+    {
+        if (!rFont.GetGlyphCache().IsGlyphCached(pGlyph->maGlyphId))
+        {
+            if (!rFont.CacheGlyphToAtlas(hDC, hFONT, pGlyph->maGlyphId, *this))
+                return false;
+        }
+    }
+
+    return true;
+}
+
+bool WinSalGraphics::DrawCachedGlyphs(const CommonSalLayout& rLayout)
+{
+    HDC hDC = getHDC();
+
+    Rectangle aRect;
+    rLayout.GetBoundRect(*this, aRect);
+
+    COLORREF color = GetTextColor(hDC);
+    SalColor salColor = MAKE_SALCOLOR(GetRValue(color), GetGValue(color), GetBValue(color));
+
+    WinOpenGLSalGraphicsImpl *pImpl = dynamic_cast<WinOpenGLSalGraphicsImpl*>(mpImpl.get());
+    if (!pImpl)
+        return false;
+
+    WinFontInstance& rFont = rLayout.getWinFontInstance();
+
+    int nStart = 0;
+    Point aPos(0, 0);
+    const GlyphItem* pGlyph;
+    while (rLayout.GetNextGlyphs(1, &pGlyph, aPos, nStart))
+    {
+        OpenGLGlyphDrawElement& rElement(rFont.GetGlyphCache().GetDrawElement(pGlyph->maGlyphId));
+        OpenGLTexture& rTexture = rElement.maTexture;
+
+        if (!rTexture)
+            return false;
+
+        SalTwoRect a2Rects(0, 0,
+                           rTexture.GetWidth(), rTexture.GetHeight(),
+                           aPos.X() - rElement.getExtraOffset() + rElement.maLeftOverhangs,
+                           aPos.Y() - rElement.mnBaselineOffset - rElement.getExtraOffset(),
+                           rTexture.GetWidth(), rTexture.GetHeight());
+
+        pImpl->DeferredTextDraw(rTexture, salColor, a2Rects);
+    }
+
+    return true;
+}
+
 void WinSalGraphics::DrawTextLayout(const CommonSalLayout& rLayout, HDC hDC, bool bUseDWrite)
 {
     Point aPos(0, 0);
@@ -684,6 +748,11 @@ void WinSalGraphics::DrawTextLayout(const CommonSalLayout& rLayout)
         // no OpenGL, just classic rendering
         DrawTextLayout(rLayout, hDC, false);
     }
+    else if (CacheGlyphs(rLayout) &&
+             DrawCachedGlyphs(rLayout))
+    {
+        // Nothing
+    }
     else
     {
         // We have to render the text to a hidden texture, and draw it.