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      1 /*
      2  * Copyright 2012 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 SkPictureUtils_DEFINED
      9 #define SkPictureUtils_DEFINED
     10 
     11 #include "SkPicture.h"
     12 #include "SkTDArray.h"
     13 
     14 class SkData;
     15 struct SkRect;
     16 
     17 class SK_API SkPictureUtils {
     18 public:
     19     /**
     20      *  Given a rectangular visible "window" into the picture, return an array
     21      *  of SkPixelRefs that might intersect that area. To keep the call fast,
     22      *  the returned list is not guaranteed to be exact, so it may miss some,
     23      *  and it may return false positives.
     24      *
     25      *  The pixelrefs returned in the SkData are already owned by the picture,
     26      *  so the returned pointers are only valid while the picture is in scope
     27      *  and remains unchanged.
     28      */
     29     static SkData* GatherPixelRefs(const SkPicture* pict, const SkRect& area);
     30 
     31     /**
     32      * SkPixelRefContainer provides a base class for more elaborate pixel ref
     33      * query structures (e.g., rtrees, quad-trees, etc.)
     34      */
     35     class SkPixelRefContainer : public SkRefCnt {
     36     public:
     37         virtual void add(SkPixelRef* pr, const SkRect& rect) = 0;
     38 
     39         // The returned array may contain duplicates
     40         virtual void query(const SkRect& queryRect, SkTDArray<SkPixelRef*> *result) = 0;
     41 
     42     private:
     43         typedef SkRefCnt INHERITED;
     44     };
     45 
     46     // Simple query structure that just stores a linked list of pixel refs
     47     // and rects.
     48     class SkPixelRefsAndRectsList : public SkPixelRefContainer {
     49     public:
     50         virtual void add(SkPixelRef* pr, const SkRect& rect) SK_OVERRIDE {
     51             PixelRefAndRect *dst = fArray.append();
     52 
     53             dst->fPixelRef = pr;
     54             dst->fRect = rect;
     55         }
     56 
     57         virtual void query(const SkRect& queryRect, SkTDArray<SkPixelRef*> *result) SK_OVERRIDE {
     58             for (int i = 0; i < fArray.count(); ++i) {
     59                 if (SkRect::Intersects(fArray[i].fRect, queryRect)) {
     60                     *result->append() = fArray[i].fPixelRef;
     61                 }
     62             }
     63         }
     64 
     65     private:
     66         struct PixelRefAndRect {
     67             SkPixelRef* fPixelRef;
     68             SkRect      fRect;
     69         };
     70 
     71         SkTDArray<PixelRefAndRect> fArray;
     72 
     73         typedef SkPixelRefContainer INHERITED;
     74     };
     75 
     76     /**
     77      *  Fill the provided pixel ref container with the picture's pixel ref
     78      *  and rect information.
     79      */
     80     static void GatherPixelRefsAndRects(SkPicture* pict, SkPixelRefContainer* prCont);
     81 };
     82 
     83 #endif
     84