src/third_party/skia/include/effects/SkBlurDrawLooper.h

   1 /*
   2  * Copyright 2008 The Android Open Source Project
   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
   9 #ifndef SkBlurDrawLooper_DEFINED
  10 #define SkBlurDrawLooper_DEFINED
  11
  12 #include "SkDrawLooper.h"
  13 #include "SkColor.h"
  14
  15 class SkMaskFilter;
  16 class SkColorFilter;
  17
  18 /** \class SkBlurDrawLooper
  19     This class draws a shadow of the object (possibly offset), and then draws
  20     the original object in its original position.
  21     should there be an option to just draw the shadow/blur layer? webkit?
  22 */
  23 class SK_API SkBlurDrawLooper : public SkDrawLooper {
  24 public:
  25     enum BlurFlags {
  26         kNone_BlurFlag = 0x00,
  27         /**
  28             The blur layer's dx/dy/radius aren't affected by the canvas
  29             transform.
  30         */
  31         kIgnoreTransform_BlurFlag   = 0x01,
  32         kOverrideColor_BlurFlag     = 0x02,
  33         kHighQuality_BlurFlag       = 0x04,
  34         /** mask for all blur flags */
  35         kAll_BlurFlag               = 0x07
  36     };
  37
  38     static SkBlurDrawLooper* Create(SkColor color, SkScalar sigma, SkScalar dx, SkScalar dy,
  39                                     uint32_t flags = kNone_BlurFlag) {
  40         return SkNEW_ARGS(SkBlurDrawLooper, (color, sigma, dx, dy, flags));
  41     }
  42
  43     virtual ~SkBlurDrawLooper();
  44
  45     virtual SkDrawLooper::Context* createContext(SkCanvas*, void* storage) const SK_OVERRIDE;
  46
  47     virtual size_t contextSize() const SK_OVERRIDE { return sizeof(BlurDrawLooperContext); }
  48
  49     SK_TO_STRING_OVERRIDE()
  50     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkBlurDrawLooper)
  51
  52 protected:
  53     SkBlurDrawLooper(SkColor color, SkScalar sigma, SkScalar dx, SkScalar dy,
  54                      uint32_t flags);
  55
  56 #ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
  57     SkBlurDrawLooper(SkReadBuffer&);
  58 #endif
  59     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
  60
  61     virtual bool asABlurShadow(BlurShadowRec*) const SK_OVERRIDE;
  62
  63 private:
  64     SkMaskFilter*   fBlur;
  65     SkColorFilter*  fColorFilter;
  66     SkScalar        fDx, fDy, fSigma;
  67     SkColor         fBlurColor;
  68     uint32_t        fBlurFlags;
  69
  70     enum State {
  71         kBeforeEdge,
  72         kAfterEdge,
  73         kDone
  74     };
  75
  76     class BlurDrawLooperContext : public SkDrawLooper::Context {
  77     public:
  78         explicit BlurDrawLooperContext(const SkBlurDrawLooper* looper);
  79
  80         virtual bool next(SkCanvas* canvas, SkPaint* paint) SK_OVERRIDE;
  81
  82     private:
  83         const SkBlurDrawLooper* fLooper;
  84         State fState;
  85     };
  86
  87     void init(SkScalar sigma, SkScalar dx, SkScalar dy, SkColor color, uint32_t flags);
  88     void initEffects();
  89
  90     typedef SkDrawLooper INHERITED;
  91 };
  92
  93 #endif