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      1 
      2 /*
      3  * Copyright 2006 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 SkView_DEFINED
     11 #define SkView_DEFINED
     12 
     13 #include "SkEventSink.h"
     14 #include "SkRect.h"
     15 #include "SkMatrix.h"
     16 #include "SkMetaData.h"
     17 
     18 class SkCanvas;
     19 
     20 /** \class SkView
     21 
     22     SkView is the base class for screen management. All widgets and controls inherit
     23     from SkView.
     24 */
     25 class SkView : public SkEventSink {
     26 public:
     27     enum Flag_Shift {
     28         kVisible_Shift,
     29         kNoClip_Shift,
     30 
     31         kFlagShiftCount
     32     };
     33     enum Flag_Mask {
     34         kVisible_Mask   = 1 << kVisible_Shift,      //!< set if the view is visible
     35         kNoClip_Mask    = 1 << kNoClip_Shift,        //!< set if the view is not clipped to its bounds
     36 
     37         kAllFlagMasks   = (uint32_t)(0 - 1) >> (32 - kFlagShiftCount)
     38     };
     39 
     40                 SkView(uint32_t flags = 0);
     41     virtual     ~SkView();
     42 
     43     /** Return the flags associated with the view
     44     */
     45     uint32_t    getFlags() const { return fFlags; }
     46     /** Set the flags associated with the view
     47     */
     48     void        setFlags(uint32_t flags);
     49 
     50     /** Helper that returns non-zero if the kVisible_Mask bit is set in the view's flags
     51     */
     52     int         isVisible() const { return fFlags & kVisible_Mask; }
     53     int         isClipToBounds() const { return !(fFlags & kNoClip_Mask); }
     54     /** Helper to set/clear the view's kVisible_Mask flag */
     55     void        setVisibleP(bool);
     56     void        setClipToBounds(bool);
     57 
     58     /** Return the view's width */
     59     SkScalar    width() const { return fWidth; }
     60     /** Return the view's height */
     61     SkScalar    height() const { return fHeight; }
     62     /** Set the view's width and height. These must both be >= 0. This does not affect the view's loc */
     63     void        setSize(SkScalar width, SkScalar height);
     64     void        setSize(const SkPoint& size) { this->setSize(size.fX, size.fY); }
     65     void        setWidth(SkScalar width) { this->setSize(width, fHeight); }
     66     void        setHeight(SkScalar height) { this->setSize(fWidth, height); }
     67 
     68     /** Call this to have the view draw into the specified canvas. */
     69     virtual void draw(SkCanvas* canvas);
     70 
     71     //  Click handling
     72 
     73     class Click {
     74     public:
     75         Click(SkView* target);
     76         virtual ~Click();
     77 
     78         enum State {
     79             kDown_State,
     80             kMoved_State,
     81             kUp_State
     82         };
     83         SkPoint     fOrig, fPrev, fCurr;
     84         SkIPoint    fIOrig, fIPrev, fICurr;
     85         State       fState;
     86         unsigned    fModifierKeys;
     87 
     88         SkMetaData  fMeta;
     89     private:
     90         SkEventSinkID   fTargetID;
     91 
     92         friend class SkView;
     93     };
     94     Click*  findClickHandler(SkScalar x, SkScalar y, unsigned modifierKeys);
     95 
     96     static void DoClickDown(Click*, int x, int y, unsigned modi);
     97     static void DoClickMoved(Click*, int x, int y, unsigned modi);
     98     static void DoClickUp(Click*, int x, int y, unsigned modi);
     99 
    100 protected:
    101     /** Override this to draw inside the view. Be sure to call the inherited version too */
    102     virtual void    onDraw(SkCanvas*);
    103     /** Override this to be notified when the view's size changes. Be sure to call the inherited version too */
    104     virtual void    onSizeChange();
    105 
    106     /** Override this if you might handle the click
    107     */
    108     virtual Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi);
    109     /** Override this to track clicks, returning true as long as you want to track
    110         the pen/mouse.
    111     */
    112     virtual bool    onClick(Click*);
    113 
    114 private:
    115     SkScalar    fWidth, fHeight;
    116     uint8_t     fFlags;
    117 };
    118 
    119 #endif
    120