Factor text size device mapping in SkScalerContext.

src/ports/SkFontHost_FreeType.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAdvancedTypefaceMetrics.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
@@ skipping 799 matching lines @@
     // load the font file
     fStrikeIndex = -1;
     fFTSize = NULL;
     fFace = NULL;
     fFaceRec = ref_ft_face(typeface);
     if (NULL == fFaceRec) {
         return;
     }
     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());
     fMatrix22.yy = SkScalarToFixed(fMatrix22Scalar.getScaleY());
 
     fLCDIsVert = SkToBool(fRec.fFlags & SkScalerContext::kLCD_Vertical_Flag);
 
     // compute the flags we send to Load_Glyph
     bool linearMetrics = SkToBool(fRec.fFlags & SkScalerContext::kSubpixelPositioning_Flag);
     {
@@ skipping 867 matching lines @@
     if (style) {
         *style = SkFontStyle(weight, width, slant);
     }
     if (isFixedPitch) {
         *isFixedPitch = FT_IS_FIXED_WIDTH(face);
     }
 
     FT_Done_Face(face);
     return true;
 }