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; }
 
+    /**
+    *  Return the axis (if any) that the baseline for horizontal text should land on.
+    *  As an example, the identity matrix will return kX_SkAxisAlignment
+    *  If glyphs landing on the baseline is not significant (no hinting), returns
+    *  kNone_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