third_party/WebKit/Source/web/PageOverlay.cpp

/*
 * Copyright (C) 2011 Google 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
 * 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 GOOGLE INC. AND ITS CONTRIBUTORS
 * "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 GOOGLE INC.
 * OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "web/PageOverlay.h"

#include "core/frame/FrameHost.h"
#include "core/frame/VisualViewport.h"
#include "core/page/Page.h"
#include "core/page/scrolling/ScrollingCoordinator.h"
#include "platform/graphics/GraphicsContext.h"
#include "platform/graphics/GraphicsLayer.h"
#include "platform/graphics/GraphicsLayerClient.h"
#include "platform/scroll/MainThreadScrollingReason.h"
#include "public/platform/WebLayer.h"
#include "public/web/WebViewClient.h"
#include "web/WebDevToolsAgentImpl.h"
#include "web/WebViewImpl.h"
#include "wtf/PtrUtil.h"
#include <memory>

namespace blink {

std::unique_ptr<PageOverlay> PageOverlay::create(
    WebViewImpl* viewImpl,
    std::unique_ptr<PageOverlay::Delegate> delegate) {
  return wrapUnique(new PageOverlay(viewImpl, std::move(delegate)));
}

PageOverlay::PageOverlay(WebViewImpl* viewImpl,
                         std::unique_ptr<PageOverlay::Delegate> delegate)
    : m_viewImpl(viewImpl), m_delegate(std::move(delegate)) {}

PageOverlay::~PageOverlay() {
  if (!m_layer)
    return;

  m_layer->removeFromParent();
  if (WebDevToolsAgentImpl* devTools = m_viewImpl->mainFrameDevToolsAgentImpl())
    devTools->didRemovePageOverlay(m_layer.get());
  m_layer = nullptr;
}

void PageOverlay::update() {
  if (!m_viewImpl->isAcceleratedCompositingActive())
    return;

  Page* page = m_viewImpl->page();
  if (!page)
    return;

  if (!page->mainFrame()->isLocalFrame())
    return;

  if (!m_layer) {
    m_layer = GraphicsLayer::create(this);
    m_layer->setDrawsContent(true);

    if (WebDevToolsAgentImpl* devTools =
            m_viewImpl->mainFrameDevToolsAgentImpl())
      devTools->willAddPageOverlay(m_layer.get());

    // This is required for contents of overlay to stay in sync with the page
    // while scrolling.
    WebLayer* platformLayer = m_layer->platformLayer();
    platformLayer->addMainThreadScrollingReasons(
        MainThreadScrollingReason::kPageOverlay);
    page->frameHost().visualViewport().containerLayer()->addChild(
        m_layer.get());
  }

  FloatSize size(page->frameHost().visualViewport().size());
  if (size != m_layer->size())
    m_layer->setSize(size);

  m_layer->setNeedsDisplay();
}

LayoutRect PageOverlay::visualRect() const {
  DCHECK(m_layer.get());
  return LayoutRect(FloatPoint(), m_layer->size());
}

IntRect PageOverlay::computeInterestRect(const GraphicsLayer* graphicsLayer,
                                         const IntRect&) const {
  return IntRect(IntPoint(), expandedIntSize(m_layer->size()));
}

void PageOverlay::paintContents(const GraphicsLayer* graphicsLayer,
                                GraphicsContext& gc,
                                GraphicsLayerPaintingPhase phase,
                                const IntRect& interestRect) const {
  DCHECK(m_layer);
  m_delegate->paintPageOverlay(*this, gc, interestRect.size());
}

String PageOverlay::debugName(const GraphicsLayer*) const {
  return "WebViewImpl Page Overlay Content Layer";
}

}  // namespace blink