pdf/paint_aggregator.h

   1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef PDF_PAINT_AGGREGATOR_H_
   6 #define PDF_PAINT_AGGREGATOR_H_
   7
   8 #include <vector>
   9
  10 #include "ppapi/cpp/image_data.h"
  11 #include "ppapi/cpp/rect.h"
  12 #include "ppapi/cpp/rect.h"
  13
  14 // This class is responsible for aggregating multiple invalidation and scroll
  15 // commands to produce a scroll and repaint sequence. You can use this manually
  16 // to track your updates, but most applications will use the PaintManager to
  17 // additionally handle the necessary callbacks on top of the PaintAggregator
  18 // functionality.
  19 //
  20 // See http://code.google.com/p/ppapi/wiki/2DPaintingModel
  21 class PaintAggregator {
  22  public:
  23   // Stores information about a rectangle that has finished painting.  The
  24   // PaintManager will paint it only when everything else on the screen is also
  25   // ready.
  26   struct ReadyRect {
  27     pp::Point offset;
  28     pp::Rect rect;
  29     pp::ImageData image_data;
  30   };
  31
  32   struct PaintUpdate {
  33     PaintUpdate();
  34     ~PaintUpdate();
  35
  36     // True if there is a scroll applied. This indicates that the scroll delta
  37     // and scroll_rect are nonzero (just as a convenience).
  38     bool has_scroll;
  39
  40     // The amount to scroll by. Either the X or Y may be nonzero to indicate a
  41     // scroll in that direction, but there will never be a scroll in both
  42     // directions at the same time (this will be converted to a paint of the
  43     // region instead).
  44     //
  45     // If there is no scroll, this will be (0, 0).
  46     pp::Point scroll_delta;
  47
  48     // The rectangle that should be scrolled by the scroll_delta. If there is no
  49     // scroll, this will be (0, 0, 0, 0). We only track one scroll command at
  50     // once. If there are multiple ones, they will be converted to invalidates.
  51     pp::Rect scroll_rect;
  52
  53     // A list of all the individual dirty rectangles. This is an aggregated list
  54     // of all invalidate calls. Different rectangles may be unified to produce a
  55     // minimal list with no overlap that is more efficient to paint. This list
  56     // also contains the region exposed by any scroll command.
  57     std::vector<pp::Rect> paint_rects;
  58   };
  59
  60   PaintAggregator();
  61
  62   // There is a PendingUpdate if InvalidateRect or ScrollRect were called and
  63   // ClearPendingUpdate was not called.
  64   bool HasPendingUpdate() const;
  65   void ClearPendingUpdate();
  66
  67   PaintUpdate GetPendingUpdate();
  68
  69   // Sets the result of a call to the plugin to paint.  This includes rects that
  70   // are finished painting (ready), and ones that are still in-progress
  71   // (pending).
  72   void SetIntermediateResults(const std::vector<ReadyRect>& ready,
  73                               const std::vector<pp::Rect>& pending);
  74
  75   // Returns the rectangles that are ready to be painted.
  76   std::vector<ReadyRect> GetReadyRects() const;
  77
  78   // The given rect should be repainted.
  79   void InvalidateRect(const pp::Rect& rect);
  80
  81   // The given rect should be scrolled by the given amounts.
  82   void ScrollRect(const pp::Rect& clip_rect, const pp::Point& amount);
  83
  84  private:
  85   // This structure is an internal version of PaintUpdate. It's different in
  86   // two respects:
  87   //
  88   //  - The scroll damange (area exposed by the scroll operation, if any) is
  89   //    maintained separately from the dirty rects generated by calling
  90   //    InvalidateRect. We need to know this distinction for some operations.
  91   //
  92   //  - The paint bounds union is computed on the fly so we don't have to keep
  93   //    a rectangle up-to-date as we do different operations.
  94   class InternalPaintUpdate {
  95    public:
  96     InternalPaintUpdate();
  97     ~InternalPaintUpdate();
  98
  99     // Computes the rect damaged by scrolling within |scroll_rect| by
 100     // |scroll_delta|. This rect must be repainted. It is not included in
 101     // paint_rects.
 102     pp::Rect GetScrollDamage() const;
 103
 104     pp::Point scroll_delta;
 105     pp::Rect scroll_rect;
 106
 107     // Does not include the scroll damage rect unless
 108     // synthesized_scroll_damage_rect_ is set.
 109     std::vector<pp::Rect> paint_rects;
 110
 111     // Rectangles that are finished painting.
 112     std::vector<ReadyRect> ready_rects;
 113
 114     // Whether we have added the scroll damage rect to paint_rects yet or not.
 115     bool synthesized_scroll_damage_rect_;
 116   };
 117
 118   pp::Rect ScrollPaintRect(const pp::Rect& paint_rect,
 119                            const pp::Point& amount) const;
 120   void InvalidateScrollRect();
 121
 122   // Internal method used by InvalidateRect. If |check_scroll| is true, then the
 123   // method checks if there's a pending scroll and if so also invalidates |rect|
 124   // in the new scroll position.
 125   void InvalidateRectInternal(const pp::Rect& rect, bool check_scroll);
 126
 127   InternalPaintUpdate update_;
 128 };
 129
 130 #endif  // PDF_PAINT_AGGREGATOR_H_