third_party/WebKit/Source/core/editing/CaretDisplayItemClient.h

/*
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
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 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
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#ifndef CaretDisplayItemClient_h
#define CaretDisplayItemClient_h

#include "base/macros.h"
#include "core/editing/Forward.h"
#include "platform/geometry/IntRect.h"
#include "platform/geometry/LayoutRect.h"
#include "platform/graphics/Color.h"
#include "platform/graphics/paint/DisplayItem.h"

namespace blink {

class Node;
class GraphicsContext;
class LayoutBlock;
struct PaintInvalidatorContext;

class CaretDisplayItemClient final : public DisplayItemClient {
 public:
  CaretDisplayItemClient();
  virtual ~CaretDisplayItemClient();

  // TODO(yosin,wangxianzhu): Make these two static functions private or
  // combine them into updateForPaintInvalidation() when the callsites in
  // FrameCaret are removed.

  // Creating VisiblePosition causes synchronous layout so we should use the
  // PositionWithAffinity version if possible.
  // A position in HTMLTextFromControlElement is a typical example.
  static LayoutRect ComputeCaretRect(
      const PositionWithAffinity& caret_position);
  static LayoutBlock* CaretLayoutBlock(const Node*);

  // Called indirectly from LayoutBlock::clearPreviousVisualRects().
  void ClearPreviousVisualRect(const LayoutBlock&);

  // Called indirectly from LayoutBlock::willBeDestroyed().
  void LayoutBlockWillBeDestroyed(const LayoutBlock&);

  // Called when a FrameView finishes layout. Updates style and geometry of the
  // caret for paint invalidation and painting.
  void UpdateStyleAndLayoutIfNeeded(const PositionWithAffinity& caret_position);

  // Called during LayoutBlock paint invalidation.
  void InvalidatePaint(const LayoutBlock&, const PaintInvalidatorContext&);

  bool ShouldPaintCaret(const LayoutBlock& block) const {
    return &block == layout_block_;
  }
  void PaintCaret(GraphicsContext&,
                  const LayoutPoint& paint_offset,
                  DisplayItem::Type) const;

  // DisplayItemClient methods.
  LayoutRect VisualRect() const final;
  String DebugName() const final;

 private:
  friend class CaretDisplayItemClientTest;

  void InvalidatePaintInCurrentLayoutBlock(const PaintInvalidatorContext&);
  void InvalidatePaintInPreviousLayoutBlock(const PaintInvalidatorContext&);

  // These are updated by updateStyleAndLayoutIfNeeded().
  Color color_;
  LayoutRect local_rect_;
  LayoutBlock* layout_block_ = nullptr;

  // Visual rect of the caret in m_layoutBlock. This is updated by
  // invalidatePaintIfNeeded().
  LayoutRect visual_rect_;

  // These are set to the previous value of m_layoutBlock and m_visualRect
  // during updateStyleAndLayoutIfNeeded() if they haven't been set since the
  // last paint invalidation. They can only be used in invalidatePaintIfNeeded()
  // to invalidate the caret in the previous layout block.
  const LayoutBlock* previous_layout_block_ = nullptr;
  LayoutRect visual_rect_in_previous_layout_block_;

  bool needs_paint_invalidation_ = false;

  DISALLOW_COPY_AND_ASSIGN(CaretDisplayItemClient);
};

}  // namespace blink

#endif  // CaretDisplayItemClient_h