Factor text size device mapping in SkScalerContext.
All of our font back-ends use the text size in some way other than
simple concatentation with the current matrix. The code here finds
the full device matrix and then decomposes it to extract the text
size.
FreeType, GDI, and DirectWrite use the text size as the pre-hint scale.
CoreText will not scale color emoji above the requested text size,
and certain features like 'trak' are performed on the text size.
Review URL: https://codereview.chromium.org/748883005
diff --git a/src/ports/SkFontHost_FreeType.cpp b/src/ports/SkFontHost_FreeType.cpp
index d5b7985..94af9ec 100644
--- a/src/ports/SkFontHost_FreeType.cpp
+++ b/src/ports/SkFontHost_FreeType.cpp
@@ -817,56 +817,12 @@
}
fFace = fFaceRec->fFace;
- // A is the total matrix.
- SkMatrix A;
- fRec.getSingleMatrix(&A);
+ fRec.computeMatrices(SkScalerContextRec::kFull_PreMatrixScale, &fScale, &fMatrix22Scalar);
+ fMatrix22Scalar.setSkewX(-fMatrix22Scalar.getSkewX());
+ fMatrix22Scalar.setSkewY(-fMatrix22Scalar.getSkewY());
- SkScalar sx = A.getScaleX();
- SkScalar sy = A.getScaleY();
- fMatrix22Scalar.reset();
-
- // In GDI, the hinter is aware of the current transformation
- // (the transform is in some sense applied before/with the hinting).
- // The bytecode can then test if it is rotated or stretched and decide
- // to apply instructions or not.
- //
- // FreeType, however, always does the transformation strictly after hinting.
- // It just sets 'rotated' and 'stretched' to false and only applies the
- // size before hinting.
- //
- // Also, FreeType respects the head::flags::IntegerScaling flag,
- // (although this is patched out on most major distros)
- // so it is critical to get the size correct on the request.
- //
- // This also gets us the actual closest size on bitmap fonts as well.
- if (A.getSkewX() || A.getSkewY() || sx < 0 || sy < 0) {
- // h is where A maps the horizontal baseline.
- SkPoint h = SkPoint::Make(SK_Scalar1, 0);
- A.mapPoints(&h, 1);
-
- // G is the Givens Matrix for A (rotational matrix where GA[0][1] == 0).
- SkMatrix G;
- SkComputeGivensRotation(h, &G);
-
- // GA is the matrix A with rotation removed.
- SkMatrix GA(G);
- GA.preConcat(A);
-
- sx = SkScalarAbs(GA.get(SkMatrix::kMScaleX));
- sy = SkScalarAbs(GA.get(SkMatrix::kMScaleY));
-
- // sA is the total matrix A without the text scale.
- SkMatrix sA(A);
- sA.preScale(SkScalarInvert(sx), SkScalarInvert(sy)); //remove text size
-
- fMatrix22Scalar.setScaleX(sA.getScaleX());
- fMatrix22Scalar.setSkewX(-sA.getSkewX());
- fMatrix22Scalar.setSkewY(-sA.getSkewY());
- fMatrix22Scalar.setScaleY(sA.getScaleY());
- }
- fScale.set(sx, sy);
- fScaleX = SkScalarToFixed(sx);
- fScaleY = SkScalarToFixed(sy);
+ fScaleX = SkScalarToFixed(fScale.fX);
+ fScaleY = SkScalarToFixed(fScale.fY);
fMatrix22.xx = SkScalarToFixed(fMatrix22Scalar.getScaleX());
fMatrix22.xy = SkScalarToFixed(fMatrix22Scalar.getSkewX());
fMatrix22.yx = SkScalarToFixed(fMatrix22Scalar.getSkewY());