Source/WebCore/page/DebugPageOverlays.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2014-2017 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
  *    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 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 APPLE 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 (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "config.h"
 #include "DebugPageOverlays.h"

 #include "ElementIterator.h"
 #include "FrameView.h"
 #include "GraphicsContext.h"
 #include "Page.h"
 #include "PageOverlay.h"
 #include "PageOverlayController.h"
 #include "Region.h"
 #include "ScrollingCoordinator.h"
 #include "Settings.h"

 namespace WebCore {

 DebugPageOverlays* DebugPageOverlays::sharedDebugOverlays;

 class RegionOverlay : public RefCounted<RegionOverlay>, public PageOverlay::Client {
 public:
     static Ref<RegionOverlay> create(Page&, DebugPageOverlays::RegionType);
     virtual ~RegionOverlay();

     void recomputeRegion();
     PageOverlay& overlay() { return *m_overlay; }

 protected:
     RegionOverlay(Page&, Color);

 private:
     void willMoveToPage(PageOverlay&, Page*) final;
     void didMoveToPage(PageOverlay&, Page*) final;
     void drawRect(PageOverlay&, GraphicsContext&, const IntRect& dirtyRect) override;
     bool mouseEvent(PageOverlay&, const PlatformMouseEvent&) final;
     void didScrollFrame(PageOverlay&, Frame&) final;

 protected:
     // Returns true if the region changed.
     virtual bool updateRegion() = 0;
     void drawRegion(GraphicsContext&, const Region&, const Color&, const IntRect& dirtyRect);

     Page& m_page;
     RefPtr<PageOverlay> m_overlay;
     std::unique_ptr<Region> m_region;
     Color m_color;
 };

 class MouseWheelRegionOverlay final : public RegionOverlay {
 public:
     static Ref<MouseWheelRegionOverlay> create(Page& page)
     {
         return adoptRef(*new MouseWheelRegionOverlay(page));
     }

 private:
     explicit MouseWheelRegionOverlay(Page& page)
         : RegionOverlay(page, Color(0.5f, 0.0f, 0.0f, 0.4f))
     {
     }

     bool updateRegion() override;
 };

 bool MouseWheelRegionOverlay::updateRegion()
 {
     auto region = std::make_unique<Region>();

     for (const Frame* frame = &m_page.mainFrame(); frame; frame = frame->tree().traverseNext()) {
         if (!frame->view() || !frame->document())
             continue;

         auto frameRegion = frame->document()->absoluteRegionForEventTargets(frame->document()->wheelEventTargets());
         frameRegion.first.translate(toIntSize(frame->view()->contentsToRootView(IntPoint())));
         region->unite(frameRegion.first);
     }

     region->translate(m_overlay->viewToOverlayOffset());

     bool regionChanged = !m_region || !(*m_region == *region);
     m_region = WTFMove(region);
     return regionChanged;
 }

 class NonFastScrollableRegionOverlay final : public RegionOverlay {
 public:
     static Ref<NonFastScrollableRegionOverlay> create(Page& page)
     {
         return adoptRef(*new NonFastScrollableRegionOverlay(page));
     }

 private:
     explicit NonFastScrollableRegionOverlay(Page& page)
         : RegionOverlay(page, Color(1.0f, 0.5f, 0.0f, 0.4f))
     {
     }

     bool updateRegion() override;
     void drawRect(PageOverlay&, GraphicsContext&, const IntRect& dirtyRect) final;

     EventTrackingRegions m_eventTrackingRegions;
 };

 bool NonFastScrollableRegionOverlay::updateRegion()
 {
     bool regionChanged = false;

     if (ScrollingCoordinator* scrollingCoordinator = m_page.scrollingCoordinator()) {
         EventTrackingRegions eventTrackingRegions = scrollingCoordinator->absoluteEventTrackingRegions();

         if (eventTrackingRegions != m_eventTrackingRegions) {
             m_eventTrackingRegions = eventTrackingRegions;
             regionChanged = true;
         }
     }

     return regionChanged;
 }

 static const HashMap<String, Color>& touchEventRegionColors()
 {
     static const auto regionColors = makeNeverDestroyed([] {
         struct MapEntry {
             const char* name;
             int r;
             int g;
             int b;
         };
         static const MapEntry entries[] = {
             { "touchstart", 191, 191, 63 },
             { "touchmove", 63, 191, 191 },
             { "touchend", 191, 63, 127 },
             { "touchforcechange", 63, 63, 191 },
             { "wheel", 255, 128, 0 },
         };
         HashMap<String, Color> map;
         for (auto& entry : entries)
             map.add(ASCIILiteral { entry.name }, Color { entry.r, entry.g, entry.b, 80 });
         return map;
     }());
     return regionColors;
 }

 static void drawRightAlignedText(const String& text, GraphicsContext& context, const FontCascade& font, const FloatPoint& boxLocation)
 {
     float textGap = 10;
     float textBaselineFromTop = 14;

     TextRun textRun = TextRun(text);
     context.setFillColor(Color::transparent);
     float textWidth = context.drawText(font, textRun, { });
     context.setFillColor(Color::black);
     context.drawText(font, textRun, boxLocation + FloatSize(-(textWidth + textGap), textBaselineFromTop));
 }

 void NonFastScrollableRegionOverlay::drawRect(PageOverlay& pageOverlay, GraphicsContext& context, const IntRect&)
 {
     IntRect bounds = pageOverlay.bounds();

     context.clearRect(bounds);

     FloatRect legendRect = { bounds.maxX() - 30.0f, 10, 20, 20 };

     FontCascadeDescription fontDescription;
     fontDescription.setOneFamily("Helvetica");
     fontDescription.setSpecifiedSize(12);
     fontDescription.setComputedSize(12);
     fontDescription.setWeight(FontSelectionValue(500));
     FontCascade font(fontDescription, 0, 0);
     font.update(nullptr);

 #if ENABLE(TOUCH_EVENTS)
     context.setFillColor(touchEventRegionColors().get("touchstart"));
     context.fillRect(legendRect);
     drawRightAlignedText("touchstart", context, font, legendRect.location());

     legendRect.move(0, 30);
     context.setFillColor(touchEventRegionColors().get("touchmove"));
     context.fillRect(legendRect);
     drawRightAlignedText("touchmove", context, font, legendRect.location());

     legendRect.move(0, 30);
     context.setFillColor(touchEventRegionColors().get("touchend"));
     context.fillRect(legendRect);
     drawRightAlignedText("touchend", context, font, legendRect.location());

     legendRect.move(0, 30);
     context.setFillColor(touchEventRegionColors().get("touchforcechange"));
     context.fillRect(legendRect);
     drawRightAlignedText("touchforcechange", context, font, legendRect.location());

     legendRect.move(0, 30);
     context.setFillColor(m_color);
     context.fillRect(legendRect);
     drawRightAlignedText("passive listeners", context, font, legendRect.location());
 #else
     // On desktop platforms, the "wheel" region includes the non-fast scrollable region.
     context.setFillColor(touchEventRegionColors().get("wheel"));
     context.fillRect(legendRect);
     drawRightAlignedText("non-fast region", context, font, legendRect.location());
 #endif

     for (const auto& synchronousEventRegion : m_eventTrackingRegions.eventSpecificSynchronousDispatchRegions) {
         Color regionColor = touchEventRegionColors().get(synchronousEventRegion.key);
         drawRegion(context, synchronousEventRegion.value, regionColor, bounds);
     }

     drawRegion(context, m_eventTrackingRegions.asynchronousDispatchRegion, m_color, bounds);
 }

 Ref<RegionOverlay> RegionOverlay::create(Page& page, DebugPageOverlays::RegionType regionType)
 {
     switch (regionType) {
     case DebugPageOverlays::RegionType::WheelEventHandlers:
         return MouseWheelRegionOverlay::create(page);
     case DebugPageOverlays::RegionType::NonFastScrollableRegion:
         return NonFastScrollableRegionOverlay::create(page);
     }
     ASSERT_NOT_REACHED();
     return MouseWheelRegionOverlay::create(page);
 }

 RegionOverlay::RegionOverlay(Page& page, Color regionColor)
     : m_page(page)
     , m_overlay(PageOverlay::create(*this, PageOverlay::OverlayType::Document))
     , m_color(regionColor)
 {
 }

 RegionOverlay::~RegionOverlay()
 {
     if (m_overlay)
         m_page.pageOverlayController().uninstallPageOverlay(*m_overlay, PageOverlay::FadeMode::DoNotFade);
 }

 void RegionOverlay::willMoveToPage(PageOverlay&, Page* page)
 {
     if (!page)
         m_overlay = nullptr;
 }

 void RegionOverlay::didMoveToPage(PageOverlay&, Page* page)
 {
     if (page)
         recomputeRegion();
 }

 void RegionOverlay::drawRect(PageOverlay&, GraphicsContext& context, const IntRect& dirtyRect)
 {
     context.clearRect(dirtyRect);

     if (!m_region)
         return;

     drawRegion(context, *m_region, m_color, dirtyRect);
 }

 void RegionOverlay::drawRegion(GraphicsContext& context, const Region& region, const Color& color, const IntRect& dirtyRect)
 {
     GraphicsContextStateSaver saver(context);
     context.setFillColor(color);
     for (auto rect : region.rects()) {
         if (rect.intersects(dirtyRect))
             context.fillRect(rect);
     }
 }

 bool RegionOverlay::mouseEvent(PageOverlay&, const PlatformMouseEvent&)
 {
     return false;
 }

 void RegionOverlay::didScrollFrame(PageOverlay&, Frame&)
 {
 }

 void RegionOverlay::recomputeRegion()
 {
     if (updateRegion())
         m_overlay->setNeedsDisplay();
 }

 DebugPageOverlays& DebugPageOverlays::singleton()
 {
     if (!sharedDebugOverlays)
         sharedDebugOverlays = new DebugPageOverlays;

     return *sharedDebugOverlays;
 }

 static inline size_t indexOf(DebugPageOverlays::RegionType regionType)
 {
     return static_cast<size_t>(regionType);
 }

 RegionOverlay& DebugPageOverlays::ensureRegionOverlayForPage(Page& page, RegionType regionType)
 {
     auto it = m_pageRegionOverlays.find(&page);
     if (it != m_pageRegionOverlays.end()) {
         auto& visualizer = it->value[indexOf(regionType)];
         if (!visualizer)
             visualizer = RegionOverlay::create(page, regionType);
         return *visualizer;
     }

     Vector<RefPtr<RegionOverlay>> visualizers(NumberOfRegionTypes);
     auto visualizer = RegionOverlay::create(page, regionType);
     visualizers[indexOf(regionType)] = visualizer.copyRef();
     m_pageRegionOverlays.add(&page, WTFMove(visualizers));
     return visualizer;
 }

 void DebugPageOverlays::showRegionOverlay(Page& page, RegionType regionType)
 {
     auto& visualizer = ensureRegionOverlayForPage(page, regionType);
     page.pageOverlayController().installPageOverlay(visualizer.overlay(), PageOverlay::FadeMode::DoNotFade);
 }

 void DebugPageOverlays::hideRegionOverlay(Page& page, RegionType regionType)
 {
     auto it = m_pageRegionOverlays.find(&page);
     if (it == m_pageRegionOverlays.end())
         return;
     auto& visualizer = it->value[indexOf(regionType)];
     if (!visualizer)
         return;
     page.pageOverlayController().uninstallPageOverlay(visualizer->overlay(), PageOverlay::FadeMode::DoNotFade);
     visualizer = nullptr;
 }

 void DebugPageOverlays::regionChanged(Frame& frame, RegionType regionType)
 {
     auto* page = frame.page();
     if (!page)
         return;

     if (auto* visualizer = regionOverlayForPage(*page, regionType))
         visualizer->recomputeRegion();
 }

 RegionOverlay* DebugPageOverlays::regionOverlayForPage(Page& page, RegionType regionType) const
 {
     auto it = m_pageRegionOverlays.find(&page);
     if (it == m_pageRegionOverlays.end())
         return nullptr;
     return it->value.at(indexOf(regionType)).get();
 }

 void DebugPageOverlays::updateOverlayRegionVisibility(Page& page, DebugOverlayRegions visibleRegions)
 {
     if (visibleRegions & NonFastScrollableRegion)
         showRegionOverlay(page, RegionType::NonFastScrollableRegion);
     else
         hideRegionOverlay(page, RegionType::NonFastScrollableRegion);

     if (visibleRegions & WheelEventHandlerRegion)
         showRegionOverlay(page, RegionType::WheelEventHandlers);
     else
         hideRegionOverlay(page, RegionType::WheelEventHandlers);
 }

 void DebugPageOverlays::settingsChanged(Page& page)
 {
     DebugOverlayRegions activeOverlayRegions = page.settings().visibleDebugOverlayRegions();
     if (!activeOverlayRegions && !hasOverlays(page))
         return;

     DebugPageOverlays::singleton().updateOverlayRegionVisibility(page, activeOverlayRegions);
 }

 }
	/*
	* Copyright (C) 2014-2017 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
	* 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 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 APPLE 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 (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
	* THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "config.h"
	#include "DebugPageOverlays.h"

	#include "ElementIterator.h"
	#include "FrameView.h"
	#include "GraphicsContext.h"
	#include "Page.h"
	#include "PageOverlay.h"
	#include "PageOverlayController.h"
	#include "Region.h"
	#include "ScrollingCoordinator.h"
	#include "Settings.h"

	namespace WebCore {

	DebugPageOverlays* DebugPageOverlays::sharedDebugOverlays;

	class RegionOverlay : public RefCounted<RegionOverlay>, public PageOverlay::Client {
	public:
	static Ref<RegionOverlay> create(Page&, DebugPageOverlays::RegionType);
	virtual ~RegionOverlay();

	void recomputeRegion();
	PageOverlay& overlay() { return *m_overlay; }

	protected:
	RegionOverlay(Page&, Color);

	private:
	void willMoveToPage(PageOverlay&, Page*) final;
	void didMoveToPage(PageOverlay&, Page*) final;
	void drawRect(PageOverlay&, GraphicsContext&, const IntRect& dirtyRect) override;
	bool mouseEvent(PageOverlay&, const PlatformMouseEvent&) final;
	void didScrollFrame(PageOverlay&, Frame&) final;

	protected:
	// Returns true if the region changed.
	virtual bool updateRegion() = 0;
	void drawRegion(GraphicsContext&, const Region&, const Color&, const IntRect& dirtyRect);

	Page& m_page;
	RefPtr<PageOverlay> m_overlay;
	std::unique_ptr<Region> m_region;
	Color m_color;
	};

	class MouseWheelRegionOverlay final : public RegionOverlay {
	public:
	static Ref<MouseWheelRegionOverlay> create(Page& page)
	{
	return adoptRef(*new MouseWheelRegionOverlay(page));
	}

	private:
	explicit MouseWheelRegionOverlay(Page& page)
	: RegionOverlay(page, Color(0.5f, 0.0f, 0.0f, 0.4f))
	{
	}

	bool updateRegion() override;
	};

	bool MouseWheelRegionOverlay::updateRegion()
	{
	auto region = std::make_unique<Region>();

	for (const Frame* frame = &m_page.mainFrame(); frame; frame = frame->tree().traverseNext()) {
	if (!frame->view() \|\| !frame->document())
	continue;

	auto frameRegion = frame->document()->absoluteRegionForEventTargets(frame->document()->wheelEventTargets());
	frameRegion.first.translate(toIntSize(frame->view()->contentsToRootView(IntPoint())));
	region->unite(frameRegion.first);
	}

	region->translate(m_overlay->viewToOverlayOffset());

	bool regionChanged = !m_region \|\| !(m_region == region);
	m_region = WTFMove(region);
	return regionChanged;
	}

	class NonFastScrollableRegionOverlay final : public RegionOverlay {
	public:
	static Ref<NonFastScrollableRegionOverlay> create(Page& page)
	{
	return adoptRef(*new NonFastScrollableRegionOverlay(page));
	}

	private:
	explicit NonFastScrollableRegionOverlay(Page& page)
	: RegionOverlay(page, Color(1.0f, 0.5f, 0.0f, 0.4f))
	{
	}

	bool updateRegion() override;
	void drawRect(PageOverlay&, GraphicsContext&, const IntRect& dirtyRect) final;

	EventTrackingRegions m_eventTrackingRegions;
	};

	bool NonFastScrollableRegionOverlay::updateRegion()
	{
	bool regionChanged = false;

	if (ScrollingCoordinator* scrollingCoordinator = m_page.scrollingCoordinator()) {
	EventTrackingRegions eventTrackingRegions = scrollingCoordinator->absoluteEventTrackingRegions();

	if (eventTrackingRegions != m_eventTrackingRegions) {
	m_eventTrackingRegions = eventTrackingRegions;
	regionChanged = true;
	}
	}

	return regionChanged;
	}

	static const HashMap<String, Color>& touchEventRegionColors()
	{
	static const auto regionColors = makeNeverDestroyed([] {
	struct MapEntry {
	const char* name;
	int r;
	int g;
	int b;
	};
	static const MapEntry entries[] = {
	{ "touchstart", 191, 191, 63 },
	{ "touchmove", 63, 191, 191 },
	{ "touchend", 191, 63, 127 },
	{ "touchforcechange", 63, 63, 191 },
	{ "wheel", 255, 128, 0 },
	};
	HashMap<String, Color> map;
	for (auto& entry : entries)
	map.add(ASCIILiteral { entry.name }, Color { entry.r, entry.g, entry.b, 80 });
	return map;
	}());
	return regionColors;
	}

	static void drawRightAlignedText(const String& text, GraphicsContext& context, const FontCascade& font, const FloatPoint& boxLocation)
	{
	float textGap = 10;
	float textBaselineFromTop = 14;

	TextRun textRun = TextRun(text);
	context.setFillColor(Color::transparent);
	float textWidth = context.drawText(font, textRun, { });
	context.setFillColor(Color::black);
	context.drawText(font, textRun, boxLocation + FloatSize(-(textWidth + textGap), textBaselineFromTop));
	}

	void NonFastScrollableRegionOverlay::drawRect(PageOverlay& pageOverlay, GraphicsContext& context, const IntRect&)
	{
	IntRect bounds = pageOverlay.bounds();

	context.clearRect(bounds);

	FloatRect legendRect = { bounds.maxX() - 30.0f, 10, 20, 20 };

	FontCascadeDescription fontDescription;
	fontDescription.setOneFamily("Helvetica");
	fontDescription.setSpecifiedSize(12);
	fontDescription.setComputedSize(12);
	fontDescription.setWeight(FontSelectionValue(500));
	FontCascade font(fontDescription, 0, 0);
	font.update(nullptr);

	#if ENABLE(TOUCH_EVENTS)
	context.setFillColor(touchEventRegionColors().get("touchstart"));
	context.fillRect(legendRect);
	drawRightAlignedText("touchstart", context, font, legendRect.location());

	legendRect.move(0, 30);
	context.setFillColor(touchEventRegionColors().get("touchmove"));
	context.fillRect(legendRect);
	drawRightAlignedText("touchmove", context, font, legendRect.location());

	legendRect.move(0, 30);
	context.setFillColor(touchEventRegionColors().get("touchend"));
	context.fillRect(legendRect);
	drawRightAlignedText("touchend", context, font, legendRect.location());

	legendRect.move(0, 30);
	context.setFillColor(touchEventRegionColors().get("touchforcechange"));
	context.fillRect(legendRect);
	drawRightAlignedText("touchforcechange", context, font, legendRect.location());

	legendRect.move(0, 30);
	context.setFillColor(m_color);
	context.fillRect(legendRect);
	drawRightAlignedText("passive listeners", context, font, legendRect.location());
	#else
	// On desktop platforms, the "wheel" region includes the non-fast scrollable region.
	context.setFillColor(touchEventRegionColors().get("wheel"));
	context.fillRect(legendRect);
	drawRightAlignedText("non-fast region", context, font, legendRect.location());
	#endif

	for (const auto& synchronousEventRegion : m_eventTrackingRegions.eventSpecificSynchronousDispatchRegions) {
	Color regionColor = touchEventRegionColors().get(synchronousEventRegion.key);
	drawRegion(context, synchronousEventRegion.value, regionColor, bounds);
	}

	drawRegion(context, m_eventTrackingRegions.asynchronousDispatchRegion, m_color, bounds);
	}

	Ref<RegionOverlay> RegionOverlay::create(Page& page, DebugPageOverlays::RegionType regionType)
	{
	switch (regionType) {
	case DebugPageOverlays::RegionType::WheelEventHandlers:
	return MouseWheelRegionOverlay::create(page);
	case DebugPageOverlays::RegionType::NonFastScrollableRegion:
	return NonFastScrollableRegionOverlay::create(page);
	}
	ASSERT_NOT_REACHED();
	return MouseWheelRegionOverlay::create(page);
	}

	RegionOverlay::RegionOverlay(Page& page, Color regionColor)
	: m_page(page)
	, m_overlay(PageOverlay::create(*this, PageOverlay::OverlayType::Document))
	, m_color(regionColor)
	{
	}

	RegionOverlay::~RegionOverlay()
	{
	if (m_overlay)
	m_page.pageOverlayController().uninstallPageOverlay(*m_overlay, PageOverlay::FadeMode::DoNotFade);
	}

	void RegionOverlay::willMoveToPage(PageOverlay&, Page* page)
	{
	if (!page)
	m_overlay = nullptr;
	}

	void RegionOverlay::didMoveToPage(PageOverlay&, Page* page)
	{
	if (page)
	recomputeRegion();
	}

	void RegionOverlay::drawRect(PageOverlay&, GraphicsContext& context, const IntRect& dirtyRect)
	{
	context.clearRect(dirtyRect);

	if (!m_region)
	return;

	drawRegion(context, *m_region, m_color, dirtyRect);
	}

	void RegionOverlay::drawRegion(GraphicsContext& context, const Region& region, const Color& color, const IntRect& dirtyRect)
	{
	GraphicsContextStateSaver saver(context);
	context.setFillColor(color);
	for (auto rect : region.rects()) {
	if (rect.intersects(dirtyRect))
	context.fillRect(rect);
	}
	}

	bool RegionOverlay::mouseEvent(PageOverlay&, const PlatformMouseEvent&)
	{
	return false;
	}

	void RegionOverlay::didScrollFrame(PageOverlay&, Frame&)
	{
	}

	void RegionOverlay::recomputeRegion()
	{
	if (updateRegion())
	m_overlay->setNeedsDisplay();
	}

	DebugPageOverlays& DebugPageOverlays::singleton()
	{
	if (!sharedDebugOverlays)
	sharedDebugOverlays = new DebugPageOverlays;

	return *sharedDebugOverlays;
	}

	static inline size_t indexOf(DebugPageOverlays::RegionType regionType)
	{
	return static_cast<size_t>(regionType);
	}

	RegionOverlay& DebugPageOverlays::ensureRegionOverlayForPage(Page& page, RegionType regionType)
	{
	auto it = m_pageRegionOverlays.find(&page);
	if (it != m_pageRegionOverlays.end()) {
	auto& visualizer = it->value[indexOf(regionType)];
	if (!visualizer)
	visualizer = RegionOverlay::create(page, regionType);
	return *visualizer;
	}

	Vector<RefPtr<RegionOverlay>> visualizers(NumberOfRegionTypes);
	auto visualizer = RegionOverlay::create(page, regionType);
	visualizers[indexOf(regionType)] = visualizer.copyRef();
	m_pageRegionOverlays.add(&page, WTFMove(visualizers));
	return visualizer;
	}

	void DebugPageOverlays::showRegionOverlay(Page& page, RegionType regionType)
	{
	auto& visualizer = ensureRegionOverlayForPage(page, regionType);
	page.pageOverlayController().installPageOverlay(visualizer.overlay(), PageOverlay::FadeMode::DoNotFade);
	}

	void DebugPageOverlays::hideRegionOverlay(Page& page, RegionType regionType)
	{
	auto it = m_pageRegionOverlays.find(&page);
	if (it == m_pageRegionOverlays.end())
	return;
	auto& visualizer = it->value[indexOf(regionType)];
	if (!visualizer)
	return;
	page.pageOverlayController().uninstallPageOverlay(visualizer->overlay(), PageOverlay::FadeMode::DoNotFade);
	visualizer = nullptr;
	}

	void DebugPageOverlays::regionChanged(Frame& frame, RegionType regionType)
	{
	auto* page = frame.page();
	if (!page)
	return;

	if (auto* visualizer = regionOverlayForPage(*page, regionType))
	visualizer->recomputeRegion();
	}

	RegionOverlay* DebugPageOverlays::regionOverlayForPage(Page& page, RegionType regionType) const
	{
	auto it = m_pageRegionOverlays.find(&page);
	if (it == m_pageRegionOverlays.end())
	return nullptr;
	return it->value.at(indexOf(regionType)).get();
	}

	void DebugPageOverlays::updateOverlayRegionVisibility(Page& page, DebugOverlayRegions visibleRegions)
	{
	if (visibleRegions & NonFastScrollableRegion)
	showRegionOverlay(page, RegionType::NonFastScrollableRegion);
	else
	hideRegionOverlay(page, RegionType::NonFastScrollableRegion);

	if (visibleRegions & WheelEventHandlerRegion)
	showRegionOverlay(page, RegionType::WheelEventHandlers);
	else
	hideRegionOverlay(page, RegionType::WheelEventHandlers);
	}

	void DebugPageOverlays::settingsChanged(Page& page)
	{
	DebugOverlayRegions activeOverlayRegions = page.settings().visibleDebugOverlayRegions();
	if (!activeOverlayRegions && !hasOverlays(page))
	return;

	DebugPageOverlays::singleton().updateOverlayRegionVisibility(page, activeOverlayRegions);
	}

	}