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      1 
      2 /*
      3  * Copyright 2010 The Android Open Source Project
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 
     10 #ifndef SkLayer_DEFINED
     11 #define SkLayer_DEFINED
     12 
     13 #include "SkRefCnt.h"
     14 #include "SkTDArray.h"
     15 #include "SkColor.h"
     16 #include "SkMatrix.h"
     17 #include "SkPoint.h"
     18 #include "SkRect.h"
     19 #include "SkSize.h"
     20 
     21 class SkCanvas;
     22 
     23 class SkLayer : public SkRefCnt {
     24 
     25 public:
     26     SK_DECLARE_INST_COUNT(SkLayer)
     27 
     28     SkLayer();
     29     SkLayer(const SkLayer&);
     30     virtual ~SkLayer();
     31 
     32     bool isInheritFromRootTransform() const;
     33     SkScalar getOpacity() const { return m_opacity; }
     34     const SkSize& getSize() const { return m_size; }
     35     const SkPoint& getPosition() const { return m_position; }
     36     const SkPoint& getAnchorPoint() const { return m_anchorPoint; }
     37     const SkMatrix& getMatrix() const { return fMatrix; }
     38     const SkMatrix& getChildrenMatrix() const { return fChildrenMatrix; }
     39 
     40     SkScalar getWidth() const { return m_size.width(); }
     41     SkScalar getHeight() const { return m_size.height(); }
     42 
     43     void setInheritFromRootTransform(bool);
     44     void setOpacity(SkScalar opacity) { m_opacity = opacity; }
     45     void setSize(SkScalar w, SkScalar h) { m_size.set(w, h); }
     46     void setPosition(SkScalar x, SkScalar y) { m_position.set(x, y); }
     47     void setAnchorPoint(SkScalar x, SkScalar y) { m_anchorPoint.set(x, y); }
     48     void setMatrix(const SkMatrix&);
     49     void setChildrenMatrix(const SkMatrix&);
     50 
     51     // children
     52 
     53     /** Return the number of layers in our child list.
     54      */
     55     int countChildren() const;
     56 
     57     /** Return the child at the specified index (starting at 0). This does not
     58         affect the reference count of the child.
     59      */
     60     SkLayer* getChild(int index) const;
     61 
     62     /** Add this layer to our child list at the end (top-most), and ref() it.
     63         If it was already in another hierarchy, remove it from that list.
     64         Return the new child.
     65      */
     66     SkLayer* addChild(SkLayer* child);
     67 
     68     /** Remove this layer from its parent's list (or do nothing if it has no
     69         parent.) If it had a parent, then unref() is called.
     70      */
     71     void detachFromParent();
     72 
     73     /** Remove, and unref(), all of the layers in our child list.
     74      */
     75     void removeChildren();
     76 
     77     /** Return our parent layer, or NULL if we have none.
     78      */
     79     SkLayer* getParent() const { return fParent; }
     80 
     81     /** Return the root layer in this hiearchy. If this layer is the root
     82         (i.e. has no parent), then this returns itself.
     83      */
     84     SkLayer* getRootLayer() const;
     85 
     86     // coordinate system transformations
     87 
     88     /** Return, in matrix, the matix transfomations that are applied locally
     89         when this layer draws (i.e. its position and matrix/anchorPoint).
     90         This does not include the childrenMatrix, since that is only applied
     91         after this layer draws (but before its children draw).
     92      */
     93     void getLocalTransform(SkMatrix* matrix) const;
     94 
     95     /** Return, in matrix, the concatenation of transforms that are applied
     96         from this layer's root parent to the layer itself.
     97         This is the matrix that is applied to the layer during drawing.
     98      */
     99     void localToGlobal(SkMatrix* matrix) const;
    100 
    101     // paint method
    102 
    103     void draw(SkCanvas*, SkScalar opacity);
    104     void draw(SkCanvas* canvas) {
    105         this->draw(canvas, SK_Scalar1);
    106     }
    107 
    108 protected:
    109     virtual void onDraw(SkCanvas*, SkScalar opacity);
    110 
    111 private:
    112     enum Flags {
    113         kInheritFromRootTransform_Flag = 0x01
    114     };
    115 
    116     SkLayer*    fParent;
    117     SkScalar    m_opacity;
    118     SkSize      m_size;
    119     SkPoint     m_position;
    120     SkPoint     m_anchorPoint;
    121     SkMatrix    fMatrix;
    122     SkMatrix    fChildrenMatrix;
    123     uint32_t    fFlags;
    124 
    125     SkTDArray<SkLayer*> m_children;
    126 
    127     typedef SkRefCnt INHERITED;
    128 };
    129 
    130 #endif
    131