diff options
| -rwxr-xr-x | src/ports/SkFontHost_win.cpp | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/src/ports/SkFontHost_win.cpp b/src/ports/SkFontHost_win.cpp index 67927fd81c..dc248fb31d 100755 --- a/src/ports/SkFontHost_win.cpp +++ b/src/ports/SkFontHost_win.cpp @@ -616,8 +616,8 @@ SkScalerContext_GDI::SkScalerContext_GDI(SkTypeface* rawTypeface, SetGraphicsMode(fDDC, GM_ADVANCED); SetBkMode(fDDC, TRANSPARENT); - // When GDI hinting, remove the entire Y scale to prevent 'subpixel' metrics. - // When not hinting, remove only the gdiTextSize scale which will be applied by GDI. + // When GDI hinting, remove the entire Y scale from sA and GsA. (Prevents 'linear' metrics.) + // When not hinting, remove only the integer Y scale from sA and GsA. (Applied by GDI.) SkScalerContextRec::PreMatrixScale scaleConstraints = (fRec.getHinting() == SkPaint::kNo_Hinting || fRec.getHinting() == SkPaint::kSlight_Hinting) ? SkScalerContextRec::kVerticalInteger_PreMatrixScale @@ -633,7 +633,19 @@ SkScalerContext_GDI::SkScalerContext_GDI(SkTypeface* rawTypeface, fGsA.eM21 = SkScalarToFIXED(-GsA.get(SkMatrix::kMSkewX)); fGsA.eM22 = SkScalarToFIXED(GsA.get(SkMatrix::kMScaleY)); - SkScalar gdiTextSize = scale.fY; + // When not hinting, scale was computed with kVerticalInteger, so is already an integer. + // The sA and GsA transforms will be used to create 'linear' metrics. + + // When hinting, scale was computed with kVertical, stating that our port can handle + // non-integer scales. This is done so that sA and GsA are computed without any 'residual' + // scale in them, preventing 'linear' metrics. However, GDI cannot actually handle non-integer + // scales so we need to round in this case. This is fine, since all of the scale has been + // removed from sA and GsA, so GDI will be handling the scale completely. + SkScalar gdiTextSize = SkScalarRoundToScalar(scale.fY); + + // GDI will not accept a size of zero, so round the range [0, 1] to 1. + // If the size was non-zero, the scale factors will also be non-zero and 1px tall text is drawn. + // If the size actually was zero, the scale factors will also be zero, so GDI will draw nothing. if (gdiTextSize == 0) { gdiTextSize = SK_Scalar1; } |