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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 class SkLayerView;
20 class SkDOM;
21 struct SkDOMNode;
22 
23 /** \class SkView
24 
25     SkView is the base class for screen management. All widgets and controls inherit
26     from SkView.
27 */
28 class SkView : public SkEventSink {
29 public:
30     enum Flag_Shift {
31         kVisible_Shift,
32         kEnabled_Shift,
33         kFocusable_Shift,
34         kFlexH_Shift,
35         kFlexV_Shift,
36         kNoClip_Shift,
37 
38         kFlagShiftCount
39     };
40     enum Flag_Mask {
41         kVisible_Mask   = 1 << kVisible_Shift,      //!< set if the view is visible
42         kEnabled_Mask   = 1 << kEnabled_Shift,      //!< set if the view is enabled
43         kFocusable_Mask = 1 << kFocusable_Shift,    //!< set if the view can receive focus
44         kFlexH_Mask     = 1 << kFlexH_Shift,        //!< set if the view's width is stretchable
45         kFlexV_Mask     = 1 << kFlexV_Shift,        //!< set if the view's height is stretchable
46         kNoClip_Mask    = 1 << kNoClip_Shift,        //!< set if the view is not clipped to its bounds
47 
48         kAllFlagMasks   = (uint32_t)(0 - 1) >> (32 - kFlagShiftCount)
49     };
50 
51                 SkView(uint32_t flags = 0);
52     virtual     ~SkView();
53 
54     /** Return the flags associated with the view
55     */
getFlags()56     uint32_t    getFlags() const { return fFlags; }
57     /** Set the flags associated with the view
58     */
59     void        setFlags(uint32_t flags);
60 
61     /** Helper that returns non-zero if the kVisible_Mask bit is set in the view's flags
62     */
isVisible()63     int         isVisible() const { return fFlags & kVisible_Mask; }
isEnabled()64     int         isEnabled() const { return fFlags & kEnabled_Mask; }
isFocusable()65     int         isFocusable() const { return fFlags & kFocusable_Mask; }
isClipToBounds()66     int         isClipToBounds() const { return !(fFlags & kNoClip_Mask); }
67     /** Helper to set/clear the view's kVisible_Mask flag */
68     void        setVisibleP(bool);
69     void        setEnabledP(bool);
70     void        setFocusableP(bool);
71     void        setClipToBounds(bool);
72 
73     /** Return the view's width */
width()74     SkScalar    width() const { return fWidth; }
75     /** Return the view's height */
height()76     SkScalar    height() const { return fHeight; }
77     /** Set the view's width and height. These must both be >= 0. This does not affect the view's loc */
78     void        setSize(SkScalar width, SkScalar height);
setSize(const SkPoint & size)79     void        setSize(const SkPoint& size) { this->setSize(size.fX, size.fY); }
setWidth(SkScalar width)80     void        setWidth(SkScalar width) { this->setSize(width, fHeight); }
setHeight(SkScalar height)81     void        setHeight(SkScalar height) { this->setSize(fWidth, height); }
82     /** Return a rectangle set to [0, 0, width, height] */
83     void        getLocalBounds(SkRect* bounds) const;
84 
85     /** Loc - the view's offset with respect to its parent in its view hiearchy.
86         NOTE: For more complex transforms, use Local Matrix. The tranformations
87         are applied in the following order:
88              canvas->translate(fLoc.fX, fLoc.fY);
89              canvas->concat(fMatrix);
90     */
91     /** Return the view's left edge */
locX()92     SkScalar    locX() const { return fLoc.fX; }
93     /** Return the view's top edge */
locY()94     SkScalar    locY() const { return fLoc.fY; }
95     /** Set the view's left and top edge. This does not affect the view's size */
96     void        setLoc(SkScalar x, SkScalar y);
setLoc(const SkPoint & loc)97     void        setLoc(const SkPoint& loc) { this->setLoc(loc.fX, loc.fY); }
setLocX(SkScalar x)98     void        setLocX(SkScalar x) { this->setLoc(x, fLoc.fY); }
setLocY(SkScalar y)99     void        setLocY(SkScalar y) { this->setLoc(fLoc.fX, y); }
100 
101     /** Local Matrix - matrix used to tranform the view with respect to its
102         parent in its view hiearchy. Use setLocalMatrix to apply matrix
103         transformations to the current view and in turn affect its children.
104         NOTE: For simple offsets, use Loc. The transformations are applied in
105         the following order:
106              canvas->translate(fLoc.fX, fLoc.fY);
107              canvas->concat(fMatrix);
108     */
getLocalMatrix()109     const SkMatrix& getLocalMatrix() const { return fMatrix; }
110     void            setLocalMatrix(const SkMatrix& matrix);
111 
112     /** Offset (move) the view by the specified dx and dy. This does not affect the view's size */
113     void        offset(SkScalar dx, SkScalar dy);
114 
115     /** Call this to have the view draw into the specified canvas. */
116     virtual void draw(SkCanvas* canvas);
117 
118     /** Call this to invalidate part of all of a view, requesting that the view's
119         draw method be called. The rectangle parameter specifies the part of the view
120         that should be redrawn. If it is null, it specifies the entire view bounds.
121     */
122     void        inval(SkRect* rectOrNull);
123 
124     //  Focus management
125 
126     SkView* getFocusView() const;
127     bool    hasFocus() const;
128 
129     enum FocusDirection {
130         kNext_FocusDirection,
131         kPrev_FocusDirection,
132 
133         kFocusDirectionCount
134     };
135     bool    acceptFocus();
136     SkView* moveFocus(FocusDirection);
137 
138     //  Click handling
139 
140     class Click {
141     public:
142         Click(SkView* target);
143         virtual ~Click();
144 
getType()145         const char* getType() const { return fType; }
146         bool        isType(const char type[]) const;
147         void        setType(const char type[]);     // does NOT make a copy of the string
148         void        copyType(const char type[]);    // makes a copy of the string
149 
150         enum State {
151             kDown_State,
152             kMoved_State,
153             kUp_State
154         };
155         SkPoint     fOrig, fPrev, fCurr;
156         SkIPoint    fIOrig, fIPrev, fICurr;
157         State       fState;
158         void*       fOwner;
159         unsigned    fModifierKeys;
160 
161         SkMetaData  fMeta;
162     private:
163         SkEventSinkID   fTargetID;
164         char*           fType;
165         bool            fWeOwnTheType;
166 
167         void resetType();
168 
169         friend class SkView;
170     };
171     Click*  findClickHandler(SkScalar x, SkScalar y, unsigned modifierKeys);
172 
173     static void DoClickDown(Click*, int x, int y, unsigned modi);
174     static void DoClickMoved(Click*, int x, int y, unsigned modi);
175     static void DoClickUp(Click*, int x, int y, unsigned modi);
176 
177     /** Send the event to the view's parent, and its parent etc. until one of them
178         returns true from its onEvent call. This view is returned. If no parent handles
179         the event, null is returned.
180      */
181     SkView*     sendEventToParents(const SkEvent&);
182     /** Send the query to the view's parent, and its parent etc. until one of them
183         returns true from its onQuery call. This view is returned. If no parent handles
184         the query, null is returned.
185      */
186     SkView* sendQueryToParents(SkEvent*);
187 
188     //  View hierarchy management
189 
190     /** Return the view's parent, or null if it has none. This does not affect the parent's reference count. */
getParent()191     SkView*     getParent() const { return fParent; }
192     SkView*     attachChildToFront(SkView* child);
193     /** Attach the child view to this view, and increment the child's reference count. The child view is added
194         such that it will be drawn before all other child views.
195         The child view parameter is returned.
196     */
197     SkView*     attachChildToBack(SkView* child);
198     /** If the view has a parent, detach the view from its parent and decrement the view's reference count.
199         If the parent was the only owner of the view, this will cause the view to be deleted.
200     */
201     void        detachFromParent();
202     /** Attach the child view to this view, and increment the child's reference count. The child view is added
203         such that it will be drawn after all other child views.
204         The child view parameter is returned.
205     */
206     /** Detach all child views from this view. */
207     void        detachAllChildren();
208 
209     /** Convert the specified point from global coordinates into view-local coordinates
210      *  Return true on success; false on failure
211      */
globalToLocal(SkPoint * pt)212     bool        globalToLocal(SkPoint* pt) const {
213         if (pt) {
214             return this->globalToLocal(pt->fX, pt->fY, pt);
215         }
216         return true;  // nothing to do so return true
217     }
218     /** Convert the specified x,y from global coordinates into view-local coordinates, returning
219         the answer in the local parameter.
220     */
221     bool        globalToLocal(SkScalar globalX, SkScalar globalY, SkPoint* local) const;
222 
223     /** \class F2BIter
224 
225         Iterator that will return each of this view's children, in
226         front-to-back order (the order used for clicking). The first
227         call to next() returns the front-most child view. When
228         next() returns null, there are no more child views.
229     */
230     class F2BIter {
231     public:
232         F2BIter(const SkView* parent);
233         SkView* next();
234     private:
235         SkView* fFirstChild, *fChild;
236     };
237 
238     /** \class B2FIter
239 
240         Iterator that will return each of this view's children, in
241         back-to-front order (the order they are drawn). The first
242         call to next() returns the back-most child view. When
243         next() returns null, there are no more child views.
244     */
245     class B2FIter {
246     public:
247         B2FIter(const SkView* parent);
248         SkView* next();
249     private:
250         SkView* fFirstChild, *fChild;
251     };
252 
253     /** \class Artist
254 
255         Install a subclass of this in a view (calling setArtist()), and then the
256         default implementation of that view's onDraw() will invoke this object
257         automatically.
258     */
259     class Artist : public SkRefCnt {
260     public:
261 
262 
263         void draw(SkView*, SkCanvas*);
264         void inflate(const SkDOM&, const SkDOMNode*);
265     protected:
266         virtual void onDraw(SkView*, SkCanvas*) = 0;
267         virtual void onInflate(const SkDOM&, const SkDOMNode*);
268     private:
269         typedef SkRefCnt INHERITED;
270     };
271     /** Return the artist attached to this view (or null). The artist's reference
272         count is not affected.
273     */
274     Artist* getArtist() const;
275     /** Attach the specified artist (or null) to the view, replacing any existing
276         artist. If the new artist is not null, its reference count is incremented.
277         The artist parameter is returned.
278     */
279     Artist* setArtist(Artist* artist);
280 
281     /** \class Layout
282 
283         Install a subclass of this in a view (calling setLayout()), and then the
284         default implementation of that view's onLayoutChildren() will invoke
285         this object automatically.
286     */
287     class Layout : public SkRefCnt {
288     public:
289 
290 
291         void layoutChildren(SkView* parent);
292         void inflate(const SkDOM&, const SkDOMNode*);
293     protected:
294         virtual void onLayoutChildren(SkView* parent) = 0;
295         virtual void onInflate(const SkDOM&, const SkDOMNode*);
296     private:
297         typedef SkRefCnt INHERITED;
298     };
299 
300     /** Return the layout attached to this view (or null). The layout's reference
301         count is not affected.
302     */
303     Layout* getLayout() const;
304     /** Attach the specified layout (or null) to the view, replacing any existing
305         layout. If the new layout is not null, its reference count is incremented.
306         The layout parameter is returned.
307     */
308     Layout* setLayout(Layout*, bool invokeLayoutNow = true);
309     /** If a layout is attached to this view, call its layoutChildren() method
310     */
311     void    invokeLayout();
312 
313     /** Call this to initialize this view based on the specified XML node
314     */
315     void    inflate(const SkDOM& dom, const SkDOMNode* node);
316 
317     SkDEBUGCODE(void dump(bool recurse) const;)
318 
319 protected:
320     /** Override this to draw inside the view. Be sure to call the inherited version too */
321     virtual void    onDraw(SkCanvas*);
322     /** Override this to be notified when the view's size changes. Be sure to call the inherited version too */
323     virtual void    onSizeChange();
324     /** Override this if you want to handle an inval request from this view or one of its children.
325         Tyically this is only overridden by the by the "window". If your subclass does handle the
326         request, return true so the request will not continue to propogate to the parent.
327     */
328     virtual bool    handleInval(const SkRect*);
329     //! called once before all of the children are drawn (or clipped/translated)
beforeChildren(SkCanvas * c)330     virtual SkCanvas* beforeChildren(SkCanvas* c) { return c; }
331     //! called once after all of the children are drawn (or clipped/translated)
afterChildren(SkCanvas *)332     virtual void afterChildren(SkCanvas*) {}
333 
334     //! called right before this child's onDraw is called
beforeChild(SkView *,SkCanvas *)335     virtual void beforeChild(SkView* /*child*/, SkCanvas*) {}
336     //! called right after this child's onDraw is called
afterChild(SkView *,SkCanvas *)337     virtual void afterChild(SkView* /*child*/, SkCanvas*) {}
338 
339     /** Override this if you might handle the click
340     */
341     virtual Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi);
342     /** Override this to decide if your children are targets for a click.
343         The default returns true, in which case your children views will be
344         candidates for onFindClickHandler. Returning false wil skip the children
345         and just call your onFindClickHandler.
346      */
347     virtual bool onSendClickToChildren(SkScalar x, SkScalar y, unsigned modi);
348     /** Override this to track clicks, returning true as long as you want to track
349         the pen/mouse.
350     */
351     virtual bool    onClick(Click*);
352     /** Override this to initialize your subclass from the XML node. Be sure to call the inherited version too */
353     virtual void    onInflate(const SkDOM& dom, const SkDOMNode* node);
354     /** Override this if you want to perform post initialization work based on the ID dictionary built
355         during XML parsing. Be sure to call the inherited version too.
356     */
357 
358 public:
359 #ifdef SK_DEBUG
360     void validate() const;
361 #else
362     void validate() const {}
363 #endif
364     // default action is to inval the view
365     virtual void    onFocusChange(bool gainFocusP);
366 
367 protected:
368 
369     // override these if you're acting as a layer/host
onGetFocusView(SkView **)370     virtual bool    onGetFocusView(SkView**) const { return false; }
onSetFocusView(SkView *)371     virtual bool    onSetFocusView(SkView*) { return false; }
372 
373 private:
374     SkScalar    fWidth, fHeight;
375     SkMatrix    fMatrix;
376     SkPoint     fLoc;
377     SkView*     fParent;
378     SkView*     fFirstChild;
379     SkView*     fNextSibling;
380     SkView*     fPrevSibling;
381     uint8_t     fFlags;
382     uint8_t     fContainsFocus;
383 
384     friend class B2FIter;
385     friend class F2BIter;
386 
387     friend class SkLayerView;
388 
389     bool    setFocusView(SkView* fvOrNull);
390     SkView* acceptFocus(FocusDirection);
391     void    detachFromParent_NoLayout();
392     /** Compute the matrix to transform view-local coordinates into global ones */
393     void    localToGlobal(SkMatrix* matrix) const;
394 };
395 
396 #endif
397