third_party/WebKit/Source/core/paint/ScrollRecorder.cpp

   1 // Copyright 2015 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 #include "config.h"
   6 #include "core/paint/ScrollRecorder.h"
   7
   8 #include "platform/graphics/GraphicsContext.h"
   9 #include "platform/graphics/paint/DisplayItemList.h"
  10 #include "platform/graphics/paint/ScrollDisplayItem.h"
  11
  12 namespace blink {
  13
  14 ScrollRecorder::ScrollRecorder(GraphicsContext& context, const DisplayItemClientWrapper& client, PaintPhase phase, const IntSize& currentOffset)
  15     : m_client(client)
  16     , m_beginItemType(DisplayItem::paintPhaseToScrollType(phase))
  17     , m_context(context)
  18 {
  19     ASSERT(m_context.displayItemList());
  20     if (m_context.displayItemList()->displayItemConstructionIsDisabled())
  21         return;
  22     m_context.displayItemList()->createAndAppend<BeginScrollDisplayItem>(m_client, m_beginItemType, currentOffset);
  23 }
  24
  25 ScrollRecorder::~ScrollRecorder()
  26 {
  27     ASSERT(m_context.displayItemList());
  28     if (!m_context.displayItemList()->displayItemConstructionIsDisabled()) {
  29         if (m_context.displayItemList()->lastDisplayItemIsNoopBegin())
  30             m_context.displayItemList()->removeLastDisplayItem();
  31         else
  32             m_context.displayItemList()->createAndAppend<EndScrollDisplayItem>(m_client, DisplayItem::scrollTypeToEndScrollType(m_beginItemType));
  33     }
  34 }
  35
  36 } // namespace blink