Improve horizontal baseline detection.

src/core/SkScalerContext.h

 /*
  * 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.
  */
 
 #ifndef SkScalerContext_DEFINED
 #define SkScalerContext_DEFINED
 
 #include "SkMask.h"
 #include "SkMaskGamma.h"
 #include "SkMatrix.h"
 #include "SkPaint.h"
 #include "SkTypeface.h"
 
 class SkGlyph;
 class SkDescriptor;
 class SkMaskFilter;
 class SkPathEffect;
 class SkRasterizer;
 
+enum SkAxisAlignment {
+    kNone_SkAxisAlignment,
+    kX_SkAxisAlignment,
+    kY_SkAxisAlignment
+};
+
 /*
  *  To allow this to be forward-declared, it must be its own typename, rather
  *  than a nested struct inside SkScalerContext (where it started).
  */
 struct SkScalerContextRec {
     uint32_t    fFontID;
     SkScalar    fTextSize, fPreScaleX, fPreSkewX;
     SkScalar    fPost2x2[2][2];
     SkScalar    fFrameWidth, fMiterLimit;
 
@@ skipping 205 matching lines @@
                                   void* data);
 
     static void MakeRec(const SkPaint&, const SkSurfaceProps* surfaceProps,
                         const SkMatrix*, Rec* rec);
     static inline void PostMakeRec(const SkPaint&, Rec*);
 
     static SkMaskGamma::PreBlend GetMaskPreBlend(const Rec& rec);
 
     const Rec& getRec() const { return fRec; }
 
+    /**

[herb_g, 2016/02/29 18:37:10]

Do you want *'s aligned vertically?

[bungeman-skia, 2016/02/29 19:21:20]

So while we have a vertical bit on paint and we kinda need to support it for the
time being, we don't really support it everywhere. All the 'vertical' text in
Chrome and Android is actually positioned horizontal text.

+    *  Return the axis (if any) that the baseline for horizontal text should land on.
+    *  As an example, the identity matrix will return kX_SkAxisAlignment
+    */
+    SkAxisAlignment computeAxisAlignmentForHText();
+
+
 protected:
     Rec         fRec;
 
     /** Generates the contents of glyph.fAdvanceX and glyph.fAdvanceY.
      *  May call getMetrics if that would be just as fast.
      */
     virtual void generateAdvance(SkGlyph* glyph) = 0;
 
     /** Generates the contents of glyph.fWidth, fHeight, fTop, fLeft,
      *  as well as fAdvanceX and fAdvanceY if not already set.
@@ skipping 75 matching lines @@
     const SkMaskGamma::PreBlend fPreBlendForFilter;
 };
 
 #define kRec_SkDescriptorTag            SkSetFourByteTag('s', 'r', 'e', 'c')
 #define kPathEffect_SkDescriptorTag     SkSetFourByteTag('p', 't', 'h', 'e')
 #define kMaskFilter_SkDescriptorTag     SkSetFourByteTag('m', 's', 'k', 'f')
 #define kRasterizer_SkDescriptorTag     SkSetFourByteTag('r', 'a', 's', 't')
 
 ///////////////////////////////////////////////////////////////////////////////
 
-enum SkAxisAlignment {
-    kNone_SkAxisAlignment,
-    kX_SkAxisAlignment,
-    kY_SkAxisAlignment
-};
-
-/**
- *  Return the axis (if any) that the baseline for horizontal text will land on
- *  after running through the specified matrix.
- *
- *  As an example, the identity matrix will return kX_SkAxisAlignment
- */
-SkAxisAlignment SkComputeAxisAlignmentForHText(const SkMatrix& matrix);
-
-///////////////////////////////////////////////////////////////////////////////
-
 SkPaint::Hinting SkScalerContextRec::getHinting() const {
     unsigned hint = (fFlags & SkScalerContext::kHinting_Mask) >>
                                             SkScalerContext::kHinting_Shift;
     return static_cast<SkPaint::Hinting>(hint);
 }
 
 void SkScalerContextRec::setHinting(SkPaint::Hinting hinting) {
     fFlags = (fFlags & ~SkScalerContext::kHinting_Mask) |
                                 (hinting << SkScalerContext::kHinting_Shift);
 }
 
 
 #endif