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      1 /*
      2  * Copyright 2011 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #ifndef SkDrawProcs_DEFINED
      9 #define SkDrawProcs_DEFINED
     10 
     11 #include "SkDraw.h"
     12 #include "SkGlyph.h"
     13 
     14 bool SkDrawTreatAAStrokeAsHairline(SkScalar strokeWidth, const SkMatrix&,
     15                                    SkScalar* coverage);
     16 
     17 /**
     18  *  If the current paint is set to stroke and the stroke-width when applied to
     19  *  the matrix is <= 1.0, then this returns true, and sets coverage (simulating
     20  *  a stroke by drawing a hairline with partial coverage). If any of these
     21  *  conditions are false, then this returns false and coverage is ignored.
     22  */
     23 inline bool SkDrawTreatAsHairline(const SkPaint& paint, const SkMatrix& matrix,
     24                                   SkScalar* coverage) {
     25     if (SkPaint::kStroke_Style != paint.getStyle()) {
     26         return false;
     27     }
     28 
     29     SkScalar strokeWidth = paint.getStrokeWidth();
     30     if (0 == strokeWidth) {
     31         *coverage = SK_Scalar1;
     32         return true;
     33     }
     34 
     35     if (!paint.isAntiAlias()) {
     36         return false;
     37     }
     38 
     39     return SkDrawTreatAAStrokeAsHairline(strokeWidth, matrix, coverage);
     40 }
     41 
     42 class SkTextAlignProc {
     43 public:
     44     SkTextAlignProc(SkPaint::Align align)
     45         : fAlign(align) {
     46     }
     47 
     48     // Returns the glyph position, which may be rounded or not by the caller
     49     //   e.g. subpixel doesn't round.
     50     void operator()(const SkPoint& loc, const SkGlyph& glyph, SkPoint* dst) {
     51         if (SkPaint::kLeft_Align == fAlign) {
     52             dst->set(loc.fX, loc.fY);
     53         } else if (SkPaint::kCenter_Align == fAlign) {
     54             dst->set(loc.fX - SkFloatToScalar(glyph.fAdvanceX) / 2,
     55                      loc.fY - SkFloatToScalar(glyph.fAdvanceY) / 2);
     56         } else {
     57             SkASSERT(SkPaint::kRight_Align == fAlign);
     58             dst->set(loc.fX - SkFloatToScalar(glyph.fAdvanceX),
     59                      loc.fY - SkFloatToScalar(glyph.fAdvanceY));
     60         }
     61     }
     62 private:
     63     const SkPaint::Align fAlign;
     64 };
     65 
     66 #endif
     67