third_party/blink/renderer/core/paint/paint_layer_fragment.h

/*
 * Copyright (C) 2003, 2009, 2012 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:
 * 1. Redistributions of source code must retain the above copyright
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 * 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 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
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_PAINT_PAINT_LAYER_FRAGMENT_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_PAINT_PAINT_LAYER_FRAGMENT_H_

#include "third_party/blink/renderer/core/paint/clip_rect.h"
#include "third_party/blink/renderer/platform/wtf/allocator.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"

namespace blink {

class FragmentData;

// PaintLayerFragment is the representation of a fragment.
// https://drafts.csswg.org/css-break/#fragment
//
// Fragments are a paint/hit-testing only concept in Blink.
// Every box has at least one fragment, even if it is not paginated/fragmented.
// If a box has more than one fragment (i.e. is paginated by an ancestor), the
// fragments are called "paginated fragments". Note that this is a Blink
// vocabulary extension and doesn't come from the specification.
//
// The fragments are collected by calling PaintLayer::CollectFragments
// on every box once per paint/hit-testing operation.
struct PaintLayerFragment {
  DISALLOW_NEW();

 public:
  // See |root_fragment_data| for the coordinate space of |layer_bounds|,
  // |background_rect| and |foreground_rect|.

  // The PaintLayer's size in the space defined by |root_fragment_data|.
  // See PaintLayer::size_ for the exact rectangle.
  LayoutRect layer_bounds;

  // The rectangle used to clip the background.
  //
  // The rectangle is the rectangle-to-paint if no clip applies to the
  // fragment. It is the intersection of
  // - the visual overflow rect and
  // - all clips between |root_fragment_data->LocalBorderBoxProperties()
  //   .Clip()| (not included) and |fragment_data->PreClip()| (included).
  //
  // See PaintLayerClipper::CalculateRects.
  ClipRect background_rect;

  // The rectangle used to clip the content (foreground).
  //
  // The rectangle is the rectangle-to-paint if no clip applies to the
  // fragment. If the layer should apply overflow clip, the rectangle is the
  // intersection of |background_rect| and the overflow clip rect. Otherwise
  // it's the same as |background_rect|.
  //
  // See PaintLayerClipper::CalculateRects.
  ClipRect foreground_rect;

  // Defines the coordinate space of the above rects:
  // root_fragment_data->LocalBorderBoxProperties().Transform() +
  // root_fragment_data.PaintOffset().
  const FragmentData* root_fragment_data = nullptr;

  // The corresponding FragmentData of this structure.
  const FragmentData* fragment_data = nullptr;
};

typedef Vector<PaintLayerFragment, 1> PaintLayerFragments;

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_PAINT_PAINT_LAYER_FRAGMENT_H_