chromium/third_party/blink/renderer/core/paint/cull_rect_updater.h

// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_PAINT_CULL_RECT_UPDATER_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_PAINT_CULL_RECT_UPDATER_H_

#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/platform/graphics/paint/cull_rect.h"
#include "third_party/blink/renderer/platform/graphics/paint/property_tree_state.h"
#include "third_party/blink/renderer/platform/heap/persistent.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"

namespace blink {

class ViewTransitionSupplement;
class FragmentData;
class LayoutObject;
class PaintLayer;
struct PaintPropertiesChangeInfo;

// This class is used for updating the cull rects of PaintLayer fragments (see:
// |FragmentData::cull_rect_| and |FragmentData::contents_cull_rect_|.
// Cull rects are used as an optimization to limit painting to areas "near" the
// viewport. This update should happen during the PrePaint lifecycle stage.
//
// Dirty bits (see: |PaintLayer::NeedsCullRectUpdate()| and
// PaintLayer::DescendantNeedsCullRectUpdate()|) are used to optimize this
// update, and are cleared at the end.
class CORE_EXPORT CullRectUpdater { … };

// Used when painting with a custom top-level cull rect, e.g. when printing a
// page. It temporarily overrides the cull rects on the starting layer and
// descendant PaintLayers if needed, and restores the original cull rects when
// leaving this scope.
class CORE_EXPORT OverriddenCullRectScope { … };

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_PAINT_CULL_RECT_UPDATER_H_