Source/WebInspectorUI/UserInterface/Views/RecordingContentView.js - WebKit - Git at Google

 /*
  * Copyright (C) 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.
  */

 WI.RecordingContentView = class RecordingContentView extends WI.ContentView
 {
     constructor(representedObject)
     {
         console.assert(representedObject instanceof WI.Recording);

         super(representedObject);

         let isCanvas2D = this.representedObject.type === WI.Recording.Type.Canvas2D;
         let isCanvasBitmapRenderer = this.representedObject.type === WI.Recording.Type.CanvasBitmapRenderer;
         let isCanvasWebGL = this.representedObject.type === WI.Recording.Type.CanvasWebGL;
         let isCanvasWebGL2 = this.representedObject.type === WI.Recording.Type.CanvasWebGL2;

         this._index = NaN;
         this._action = null;
         this._snapshots = [];
         this._initialContent = null;
         this._generateContentThrottler = new Throttler(() => {
             if (isCanvas2D)
                 this._generateContentCanvas2D(this._index);
             else if (isCanvasBitmapRenderer || isCanvasWebGL || isCanvasWebGL2)
                 this._generateContentFromSnapshot(this._index);
         }, 200);

         this.element.classList.add("recording", this.representedObject.type);

         if (isCanvas2D || isCanvasBitmapRenderer || isCanvasWebGL || isCanvasWebGL2) {
             if (isCanvas2D && WI.ImageUtilities.supportsCanvasPathDebugging()) {
                 this._pathContext = null;

                 this._showPathButtonNavigationItem = new WI.ActivateButtonNavigationItem("show-path", WI.UIString("Show Path"), WI.UIString("Hide Path"), "Images/Path.svg", 16, 16);
                 this._showPathButtonNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, this._showPathButtonClicked, this);
                 this._showPathButtonNavigationItem.activated = !!WI.settings.showCanvasPath.value;
             }

             this._showGridButtonNavigationItem = new WI.ActivateButtonNavigationItem("show-grid", WI.UIString("Show Grid"), WI.UIString("Hide Grid"), "Images/NavigationItemCheckers.svg", 13, 13);
             this._showGridButtonNavigationItem.visibilityPriority = WI.NavigationItem.VisibilityPriority.Low;
             this._showGridButtonNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, this._showGridButtonClicked, this);
             this._showGridButtonNavigationItem.activated = !!WI.settings.showImageGrid.value;

             this._exportButtonNavigationItem = new WI.ButtonNavigationItem("export-recording", WI.UIString("Export"), "Images/Export.svg", 15, 15);
             this._exportButtonNavigationItem.buttonStyle = WI.ButtonNavigationItem.Style.ImageAndText;
             this._exportButtonNavigationItem.visibilityPriority = WI.NavigationItem.VisibilityPriority.High;
             this._exportButtonNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, this._handleExportNavigationItemClicked, this);
             this._updateExportButton();
         }
     }

     // Public

     get navigationItems()
     {
         let isCanvas2D = this.representedObject.type === WI.Recording.Type.Canvas2D;
         let isCanvasBitmapRenderer = this.representedObject.type === WI.Recording.Type.CanvasBitmapRenderer;
         let isCanvasWebGL = this.representedObject.type === WI.Recording.Type.CanvasWebGL;
         let isCanvasWebGL2 = this.representedObject.type === WI.Recording.Type.CanvasWebGL2;
         if (!isCanvas2D && !isCanvasBitmapRenderer && !isCanvasWebGL && !isCanvasWebGL2)
             return [];

         let navigationItems = [this._exportButtonNavigationItem, new WI.DividerNavigationItem];
         if (isCanvas2D && WI.ImageUtilities.supportsCanvasPathDebugging())
             navigationItems.push(this._showPathButtonNavigationItem);

         navigationItems.push(this._showGridButtonNavigationItem);
         return navigationItems;
     }

     get supplementalRepresentedObjects()
     {
         return this._action ? [this._action] : [];
     }

     updateActionIndex(index)
     {
         if (!this.representedObject)
             return;

         if (this._index === index)
             return;

         console.assert(index >= 0 && index < this.representedObject.actions.length);
         if (index < 0 || index >= this.representedObject.actions.length)
             return;

         this._index = index;

         this._updateSliderValue();

         this._generateContentThrottler.fire();

         this._action = this.representedObject.actions[this._index];

         this.dispatchEventToListeners(WI.ContentView.Event.SupplementalRepresentedObjectsDidChange);
     }

     shown()
     {
         super.shown();

         let isCanvas2D = this.representedObject.type === WI.Recording.Type.Canvas2D;
         let isCanvasBitmapRenderer = this.representedObject.type === WI.Recording.Type.CanvasBitmapRenderer;
         let isCanvasWebGL = this.representedObject.type === WI.Recording.Type.CanvasWebGL;
         let isCanvasWebGL2 = this.representedObject.type === WI.Recording.Type.CanvasWebGL2;
         if (isCanvas2D || isCanvasBitmapRenderer || isCanvasWebGL || isCanvasWebGL2) {
             if (isCanvas2D)
                 this._updateCanvasPath();
             this._updateImageGrid();
         }
     }

     hidden()
     {
         super.hidden();

         this._generateContentThrottler.cancel();
     }

     // Protected

     get supportsSave()
     {
         return true;
     }

     get saveData()
     {
         return {customSaveHandler: () => { this._exportRecording(); }};
     }

     initialLayout()
     {
         let previewHeader = this.element.appendChild(document.createElement("header"));

         let sliderContainer = previewHeader.appendChild(document.createElement("div"));
         sliderContainer.className = "slider-container";

         this._previewContainer = this.element.appendChild(document.createElement("div"));
         this._previewContainer.className = "preview-container";

         this._sliderValueElement = sliderContainer.appendChild(document.createElement("div"));
         this._sliderValueElement.className = "slider-value";

         this._sliderElement = sliderContainer.appendChild(document.createElement("input"));
         this._sliderElement.addEventListener("input", this._sliderChanged.bind(this));
         this._sliderElement.type = "range";
         this._sliderElement.min = 0;
         this._sliderElement.max = 0;

         if (!this.representedObject.ready) {
             this.representedObject.addEventListener(WI.Recording.Event.ProcessedAction, this._handleRecordingProcessedAction, this);

             if (!this.representedObject.processing)
                 this.representedObject.startProcessing();
         }

         this._updateSliderValue();
     }

     // Private

     _exportRecording()
     {
         let filename = this.representedObject.displayName;

         WI.FileUtilities.save({
             url: WI.FileUtilities.inspectorURLForFilename(filename + ".json"),
             content: JSON.stringify(this.representedObject.toJSON()),
             forceSaveAs: true,
         });
     }

     _exportReduction()
     {
         if (!this.representedObject.ready) {
             InspectorFrontendHost.beep();
             return;
         }

         let filename = this.representedObject.displayName;

         WI.FileUtilities.save({
             url: WI.FileUtilities.inspectorURLForFilename(filename + ".html"),
             content: this.representedObject.toHTML(),
             forceSaveAs: true,
         });
     }

     _generateContentCanvas2D(index)
     {
         let imageLoad = (event) => {
             // Loading took too long and the current action index has already changed.
             if (index !== this._index)
                 return;

             this._generateContentCanvas2D(index);
         };

         let initialState = this.representedObject.initialState;
         if (initialState.content && !this._initialContent) {
             this._initialContent = new Image;
             this._initialContent.src = initialState.content;
             this._initialContent.addEventListener("load", imageLoad);
             return;
         }

         let snapshotIndex = Math.floor(index / WI.RecordingContentView.SnapshotInterval);
         let snapshot = this._snapshots[snapshotIndex];

         let showCanvasPath = WI.ImageUtilities.supportsCanvasPathDebugging() && WI.settings.showCanvasPath.value;
         let indexOfLastBeginPathAction = Infinity;

         let actions = this.representedObject.actions;

         let applyActions = (from, to, callback) => {
             let saveCount = 0;
             snapshot.context.save();

             for (let attribute in snapshot.attributes)
                 snapshot.element[attribute] = snapshot.attributes[attribute];

             if (snapshot.content) {
                 snapshot.context.clearRect(0, 0, snapshot.element.width, snapshot.element.height);
                 snapshot.context.drawImage(snapshot.content, 0, 0);
             }

             for (let state of snapshot.states) {
                 state.apply(this.representedObject.type, snapshot.context);

                 ++saveCount;
                 snapshot.context.save();
             }

             let lastPathPoint = {};
             let subPathStartPoint = {};

             for (let i = from; i <= to; ++i) {
                 if (actions[i].name === "save")
                     ++saveCount;
                 else if (actions[i].name === "restore") {
                     if (!saveCount) // Only attempt to restore if save has been called.
                         continue;
                 }

                 actions[i].apply(snapshot.context);
             }

             if (showCanvasPath && indexOfLastBeginPathAction <= to) {
                 if (!this._pathContext) {
                     let pathCanvas = document.createElement("canvas");
                     pathCanvas.classList.add("path");
                     this._pathContext = pathCanvas.getContext("2d");
                 }

                 this._pathContext.canvas.width = snapshot.element.width;
                 this._pathContext.canvas.height = snapshot.element.height;
                 this._pathContext.clearRect(0, 0, snapshot.element.width, snapshot.element.height);

                 this._pathContext.save();

                 this._pathContext.fillStyle = "hsla(0, 0%, 100%, 0.75)";
                 this._pathContext.fillRect(0, 0, snapshot.element.width, snapshot.element.height);

                 function actionModifiesPath(action) {
                     switch (action.name) {
                     case "arc":
                     case "arcTo":
                     case "beginPath":
                     case "bezierCurveTo":
                     case "closePath":
                     case "ellipse":
                     case "lineTo":
                     case "moveTo":
                     case "quadraticCurveTo":
                     case "rect":
                         return true;
                     }

                     return false;
                 }

                 for (let i = indexOfLastBeginPathAction; i <= to; ++i) {
                     if (!actionModifiesPath(actions[i]))
                         continue;

                     lastPathPoint = {x: this._pathContext.currentX, y: this._pathContext.currentY};

                     if (i === indexOfLastBeginPathAction)
                         this._pathContext.setTransform(snapshot.context.getTransform());

                     let isMoveTo = actions[i].name === "moveTo";
                     this._pathContext.lineWidth = isMoveTo ? 0.5 : 1;
                     this._pathContext.setLineDash(isMoveTo ? [5, 5] : []);
                     this._pathContext.strokeStyle = i === to ? "red" : "black";

                     this._pathContext.beginPath();
                     if (!isEmptyObject(lastPathPoint))
                         this._pathContext.moveTo(lastPathPoint.x, lastPathPoint.y);

                     if (actions[i].name === "closePath" && !isEmptyObject(subPathStartPoint)) {
                         this._pathContext.lineTo(subPathStartPoint.x, subPathStartPoint.y);
                         subPathStartPoint = {};
                     } else {
                         actions[i].apply(this._pathContext, {nameOverride: isMoveTo ? "lineTo" : null});
                         if (isMoveTo)
                             subPathStartPoint = {x: this._pathContext.currentX, y: this._pathContext.currentY};
                     }

                     this._pathContext.stroke();
                 }

                 this._pathContext.restore();
                 this._previewContainer.appendChild(this._pathContext.canvas);
             } else if (this._pathContext)
                 this._pathContext.canvas.remove();

             snapshot.context.restore();
             while (saveCount-- > 0)
                 snapshot.context.restore();
         };

         if (!snapshot) {
             snapshot = this._snapshots[snapshotIndex] = {};
             snapshot.index = snapshotIndex * WI.RecordingContentView.SnapshotInterval;
             while (snapshot.index && actions[snapshot.index].name !== "beginPath")
                 --snapshot.index;

             snapshot.context = this.representedObject.createContext();
             snapshot.element = snapshot.context.canvas;

             let lastSnapshotIndex = snapshotIndex;
             while (--lastSnapshotIndex >= 0) {
                 if (this._snapshots[lastSnapshotIndex])
                     break;
             }

             let startIndex = 0;
             if (lastSnapshotIndex < 0) {
                 snapshot.content = this._initialContent;
                 snapshot.states = actions[0].states;
                 snapshot.attributes = Object.shallowCopy(initialState.attributes);
             } else {
                 let lastSnapshot = this._snapshots[lastSnapshotIndex];
                 snapshot.content = lastSnapshot.content;
                 snapshot.states = lastSnapshot.states;
                 snapshot.attributes = {};
                 for (let attribute in initialState.attributes)
                     snapshot.attributes[attribute] = lastSnapshot.element[attribute];

                 startIndex = lastSnapshot.index;
             }

             applyActions(startIndex, snapshot.index - 1);
             if (snapshot.index > 0)
                 snapshot.states = actions[snapshot.index - 1].states;

             snapshot.content = new Image;
             snapshot.content.src = snapshot.element.toDataURL();
             snapshot.content.addEventListener("load", imageLoad);
             return;
         }

         this._previewContainer.removeChildren();

         if (showCanvasPath) {
             indexOfLastBeginPathAction = this._index;
             while (indexOfLastBeginPathAction > snapshot.index && actions[indexOfLastBeginPathAction].name !== "beginPath")
                 --indexOfLastBeginPathAction;
         }

         applyActions(snapshot.index, this._index);

         this._previewContainer.insertAdjacentElement("afterbegin", snapshot.element);
         this._updateImageGrid();
     }

     _generateContentFromSnapshot(index)
     {
         let imageLoad = (event) => {
             // Loading took too long and the current action index has already changed.
             if (index !== this._index)
                 return;

             this._generateContentFromSnapshot(index);
         };

         let initialState = this.representedObject.initialState;
         if (initialState.content && !this._initialContent) {
             this._initialContent = new Image;
             this._initialContent.src = initialState.content;
             this._initialContent.addEventListener("load", imageLoad);
             return;
         }

         let actions = this.representedObject.actions;

         let visualIndex = index;
         while (!actions[visualIndex].isVisual && !(actions[visualIndex] instanceof WI.RecordingInitialStateAction))
             visualIndex--;

         let snapshot = this._snapshots[visualIndex];
         if (!snapshot) {
             if (actions[visualIndex].snapshot) {
                 snapshot = this._snapshots[visualIndex] = {element: new Image};
                 snapshot.element.src = actions[visualIndex].snapshot;
                 snapshot.element.addEventListener("load", imageLoad);
                 return;
             }

             if (actions[visualIndex] instanceof WI.RecordingInitialStateAction)
                 snapshot = this._snapshots[visualIndex] = {element: this._initialContent};
         }

         if (snapshot) {
             this._previewContainer.removeChildren();
             this._previewContainer.appendChild(snapshot.element);

             this._updateImageGrid();
         }
     }

     _updateExportButton()
     {
         if (this.representedObject.type === WI.Recording.Type.Canvas2D && this.representedObject.ready)
             this._exportButtonNavigationItem.tooltip = WI.UIString("Export recording (%s)\nShift-click to export a HTML reduction").format(WI.saveKeyboardShortcut.displayName);
         else
             this._exportButtonNavigationItem.tooltip = WI.UIString("Export recording (%s)").format(WI.saveKeyboardShortcut.displayName);
     }

     _updateCanvasPath()
     {
         let activated = WI.settings.showCanvasPath.value;

         if (this._showPathButtonNavigationItem.activated !== activated)
             this._generateContentCanvas2D(this._index);

         this._showPathButtonNavigationItem.activated = activated;
     }

     _updateImageGrid()
     {
         let activated = WI.settings.showImageGrid.value;
         this._showGridButtonNavigationItem.activated = activated;

         if (this.didInitialLayout && !isNaN(this._index))
             this._previewContainer.firstElementChild.classList.toggle("show-grid", activated);
     }

     _updateSliderValue()
     {
         if (!this._sliderElement)
             return;

         let visualActionIndexes = this.representedObject.visualActionIndexes;
         let visualActionIndex = 0;
         if (this._index > 0) {
             while (visualActionIndex < visualActionIndexes.length && visualActionIndexes[visualActionIndex] <= this._index)
                 visualActionIndex++;
         }

         this._sliderElement.value = visualActionIndex;
         this._sliderValueElement.textContent = WI.UIString("%d of %d").format(visualActionIndex, visualActionIndexes.length);
     }

     _showPathButtonClicked(event)
     {
         WI.settings.showCanvasPath.value = !this._showPathButtonNavigationItem.activated;

         this._updateCanvasPath();
     }

     _showGridButtonClicked(event)
     {
         WI.settings.showImageGrid.value = !this._showGridButtonNavigationItem.activated;

         this._updateImageGrid();
     }

     _handleExportNavigationItemClicked(event)
     {
         if (event.data.nativeEvent.shiftKey && this.representedObject.type === WI.Recording.Type.Canvas2D && this.representedObject.ready)
             this._exportReduction();
         else
             this._exportRecording();
     }

     _sliderChanged()
     {
         let index = 0;

         let visualActionIndex = parseInt(this._sliderElement.value) - 1;
         if (visualActionIndex !== -1)
             index = this.representedObject.visualActionIndexes[visualActionIndex];

         this.updateActionIndex(index);
     }

     _handleRecordingProcessedAction(event)
     {
         this._updateExportButton();

         this._sliderElement.max = this.representedObject.visualActionIndexes.length;
         this._updateSliderValue();

         if (this.representedObject.ready)
             this.representedObject.removeEventListener(null, null, this);
     }
 };

 WI.RecordingContentView.SnapshotInterval = 5000;
	/*
	* Copyright (C) 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.
	*/

	WI.RecordingContentView = class RecordingContentView extends WI.ContentView
	{
	constructor(representedObject)
	{
	console.assert(representedObject instanceof WI.Recording);

	super(representedObject);

	let isCanvas2D = this.representedObject.type === WI.Recording.Type.Canvas2D;
	let isCanvasBitmapRenderer = this.representedObject.type === WI.Recording.Type.CanvasBitmapRenderer;
	let isCanvasWebGL = this.representedObject.type === WI.Recording.Type.CanvasWebGL;
	let isCanvasWebGL2 = this.representedObject.type === WI.Recording.Type.CanvasWebGL2;

	this._index = NaN;
	this._action = null;
	this._snapshots = [];
	this._initialContent = null;
	this._generateContentThrottler = new Throttler(() => {
	if (isCanvas2D)
	this._generateContentCanvas2D(this._index);
	else if (isCanvasBitmapRenderer \|\| isCanvasWebGL \|\| isCanvasWebGL2)
	this._generateContentFromSnapshot(this._index);
	}, 200);

	this.element.classList.add("recording", this.representedObject.type);

	if (isCanvas2D \|\| isCanvasBitmapRenderer \|\| isCanvasWebGL \|\| isCanvasWebGL2) {
	if (isCanvas2D && WI.ImageUtilities.supportsCanvasPathDebugging()) {
	this._pathContext = null;

	this._showPathButtonNavigationItem = new WI.ActivateButtonNavigationItem("show-path", WI.UIString("Show Path"), WI.UIString("Hide Path"), "Images/Path.svg", 16, 16);
	this._showPathButtonNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, this._showPathButtonClicked, this);
	this._showPathButtonNavigationItem.activated = !!WI.settings.showCanvasPath.value;
	}

	this._showGridButtonNavigationItem = new WI.ActivateButtonNavigationItem("show-grid", WI.UIString("Show Grid"), WI.UIString("Hide Grid"), "Images/NavigationItemCheckers.svg", 13, 13);
	this._showGridButtonNavigationItem.visibilityPriority = WI.NavigationItem.VisibilityPriority.Low;
	this._showGridButtonNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, this._showGridButtonClicked, this);
	this._showGridButtonNavigationItem.activated = !!WI.settings.showImageGrid.value;

	this._exportButtonNavigationItem = new WI.ButtonNavigationItem("export-recording", WI.UIString("Export"), "Images/Export.svg", 15, 15);
	this._exportButtonNavigationItem.buttonStyle = WI.ButtonNavigationItem.Style.ImageAndText;
	this._exportButtonNavigationItem.visibilityPriority = WI.NavigationItem.VisibilityPriority.High;
	this._exportButtonNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, this._handleExportNavigationItemClicked, this);
	this._updateExportButton();
	}
	}

	// Public

	get navigationItems()
	{
	let isCanvas2D = this.representedObject.type === WI.Recording.Type.Canvas2D;
	let isCanvasBitmapRenderer = this.representedObject.type === WI.Recording.Type.CanvasBitmapRenderer;
	let isCanvasWebGL = this.representedObject.type === WI.Recording.Type.CanvasWebGL;
	let isCanvasWebGL2 = this.representedObject.type === WI.Recording.Type.CanvasWebGL2;
	if (!isCanvas2D && !isCanvasBitmapRenderer && !isCanvasWebGL && !isCanvasWebGL2)
	return [];

	let navigationItems = [this._exportButtonNavigationItem, new WI.DividerNavigationItem];
	if (isCanvas2D && WI.ImageUtilities.supportsCanvasPathDebugging())
	navigationItems.push(this._showPathButtonNavigationItem);

	navigationItems.push(this._showGridButtonNavigationItem);
	return navigationItems;
	}

	get supplementalRepresentedObjects()
	{
	return this._action ? [this._action] : [];
	}

	updateActionIndex(index)
	{
	if (!this.representedObject)
	return;

	if (this._index === index)
	return;

	console.assert(index >= 0 && index < this.representedObject.actions.length);
	if (index < 0 \|\| index >= this.representedObject.actions.length)
	return;

	this._index = index;

	this._updateSliderValue();

	this._generateContentThrottler.fire();

	this._action = this.representedObject.actions[this._index];

	this.dispatchEventToListeners(WI.ContentView.Event.SupplementalRepresentedObjectsDidChange);
	}

	shown()
	{
	super.shown();

	let isCanvas2D = this.representedObject.type === WI.Recording.Type.Canvas2D;
	let isCanvasBitmapRenderer = this.representedObject.type === WI.Recording.Type.CanvasBitmapRenderer;
	let isCanvasWebGL = this.representedObject.type === WI.Recording.Type.CanvasWebGL;
	let isCanvasWebGL2 = this.representedObject.type === WI.Recording.Type.CanvasWebGL2;
	if (isCanvas2D \|\| isCanvasBitmapRenderer \|\| isCanvasWebGL \|\| isCanvasWebGL2) {
	if (isCanvas2D)
	this._updateCanvasPath();
	this._updateImageGrid();
	}
	}

	hidden()
	{
	super.hidden();

	this._generateContentThrottler.cancel();
	}

	// Protected

	get supportsSave()
	{
	return true;
	}

	get saveData()
	{
	return {customSaveHandler: () => { this._exportRecording(); }};
	}

	initialLayout()
	{
	let previewHeader = this.element.appendChild(document.createElement("header"));

	let sliderContainer = previewHeader.appendChild(document.createElement("div"));
	sliderContainer.className = "slider-container";

	this._previewContainer = this.element.appendChild(document.createElement("div"));
	this._previewContainer.className = "preview-container";

	this._sliderValueElement = sliderContainer.appendChild(document.createElement("div"));
	this._sliderValueElement.className = "slider-value";

	this._sliderElement = sliderContainer.appendChild(document.createElement("input"));
	this._sliderElement.addEventListener("input", this._sliderChanged.bind(this));
	this._sliderElement.type = "range";
	this._sliderElement.min = 0;
	this._sliderElement.max = 0;

	if (!this.representedObject.ready) {
	this.representedObject.addEventListener(WI.Recording.Event.ProcessedAction, this._handleRecordingProcessedAction, this);

	if (!this.representedObject.processing)
	this.representedObject.startProcessing();
	}

	this._updateSliderValue();
	}

	// Private

	_exportRecording()
	{
	let filename = this.representedObject.displayName;

	WI.FileUtilities.save({
	url: WI.FileUtilities.inspectorURLForFilename(filename + ".json"),
	content: JSON.stringify(this.representedObject.toJSON()),
	forceSaveAs: true,
	});
	}

	_exportReduction()
	{
	if (!this.representedObject.ready) {
	InspectorFrontendHost.beep();
	return;
	}

	let filename = this.representedObject.displayName;

	WI.FileUtilities.save({
	url: WI.FileUtilities.inspectorURLForFilename(filename + ".html"),
	content: this.representedObject.toHTML(),
	forceSaveAs: true,
	});
	}

	_generateContentCanvas2D(index)
	{
	let imageLoad = (event) => {
	// Loading took too long and the current action index has already changed.
	if (index !== this._index)
	return;

	this._generateContentCanvas2D(index);
	};

	let initialState = this.representedObject.initialState;
	if (initialState.content && !this._initialContent) {
	this._initialContent = new Image;
	this._initialContent.src = initialState.content;
	this._initialContent.addEventListener("load", imageLoad);
	return;
	}

	let snapshotIndex = Math.floor(index / WI.RecordingContentView.SnapshotInterval);
	let snapshot = this._snapshots[snapshotIndex];

	let showCanvasPath = WI.ImageUtilities.supportsCanvasPathDebugging() && WI.settings.showCanvasPath.value;
	let indexOfLastBeginPathAction = Infinity;

	let actions = this.representedObject.actions;

	let applyActions = (from, to, callback) => {
	let saveCount = 0;
	snapshot.context.save();

	for (let attribute in snapshot.attributes)
	snapshot.element[attribute] = snapshot.attributes[attribute];

	if (snapshot.content) {
	snapshot.context.clearRect(0, 0, snapshot.element.width, snapshot.element.height);
	snapshot.context.drawImage(snapshot.content, 0, 0);
	}

	for (let state of snapshot.states) {
	state.apply(this.representedObject.type, snapshot.context);

	++saveCount;
	snapshot.context.save();
	}

	let lastPathPoint = {};
	let subPathStartPoint = {};

	for (let i = from; i <= to; ++i) {
	if (actions[i].name === "save")
	++saveCount;
	else if (actions[i].name === "restore") {
	if (!saveCount) // Only attempt to restore if save has been called.
	continue;
	}

	actions[i].apply(snapshot.context);
	}

	if (showCanvasPath && indexOfLastBeginPathAction <= to) {
	if (!this._pathContext) {
	let pathCanvas = document.createElement("canvas");
	pathCanvas.classList.add("path");
	this._pathContext = pathCanvas.getContext("2d");
	}

	this._pathContext.canvas.width = snapshot.element.width;
	this._pathContext.canvas.height = snapshot.element.height;
	this._pathContext.clearRect(0, 0, snapshot.element.width, snapshot.element.height);

	this._pathContext.save();

	this._pathContext.fillStyle = "hsla(0, 0%, 100%, 0.75)";
	this._pathContext.fillRect(0, 0, snapshot.element.width, snapshot.element.height);

	function actionModifiesPath(action) {
	switch (action.name) {
	case "arc":
	case "arcTo":
	case "beginPath":
	case "bezierCurveTo":
	case "closePath":
	case "ellipse":
	case "lineTo":
	case "moveTo":
	case "quadraticCurveTo":
	case "rect":
	return true;
	}

	return false;
	}

	for (let i = indexOfLastBeginPathAction; i <= to; ++i) {
	if (!actionModifiesPath(actions[i]))
	continue;

	lastPathPoint = {x: this._pathContext.currentX, y: this._pathContext.currentY};

	if (i === indexOfLastBeginPathAction)
	this._pathContext.setTransform(snapshot.context.getTransform());

	let isMoveTo = actions[i].name === "moveTo";
	this._pathContext.lineWidth = isMoveTo ? 0.5 : 1;
	this._pathContext.setLineDash(isMoveTo ? [5, 5] : []);
	this._pathContext.strokeStyle = i === to ? "red" : "black";

	this._pathContext.beginPath();
	if (!isEmptyObject(lastPathPoint))
	this._pathContext.moveTo(lastPathPoint.x, lastPathPoint.y);

	if (actions[i].name === "closePath" && !isEmptyObject(subPathStartPoint)) {
	this._pathContext.lineTo(subPathStartPoint.x, subPathStartPoint.y);
	subPathStartPoint = {};
	} else {
	actions[i].apply(this._pathContext, {nameOverride: isMoveTo ? "lineTo" : null});
	if (isMoveTo)
	subPathStartPoint = {x: this._pathContext.currentX, y: this._pathContext.currentY};
	}

	this._pathContext.stroke();
	}

	this._pathContext.restore();
	this._previewContainer.appendChild(this._pathContext.canvas);
	} else if (this._pathContext)
	this._pathContext.canvas.remove();

	snapshot.context.restore();
	while (saveCount-- > 0)
	snapshot.context.restore();
	};

	if (!snapshot) {
	snapshot = this._snapshots[snapshotIndex] = {};
	snapshot.index = snapshotIndex * WI.RecordingContentView.SnapshotInterval;
	while (snapshot.index && actions[snapshot.index].name !== "beginPath")
	--snapshot.index;

	snapshot.context = this.representedObject.createContext();
	snapshot.element = snapshot.context.canvas;

	let lastSnapshotIndex = snapshotIndex;
	while (--lastSnapshotIndex >= 0) {
	if (this._snapshots[lastSnapshotIndex])
	break;
	}

	let startIndex = 0;
	if (lastSnapshotIndex < 0) {
	snapshot.content = this._initialContent;
	snapshot.states = actions[0].states;
	snapshot.attributes = Object.shallowCopy(initialState.attributes);
	} else {
	let lastSnapshot = this._snapshots[lastSnapshotIndex];
	snapshot.content = lastSnapshot.content;
	snapshot.states = lastSnapshot.states;
	snapshot.attributes = {};
	for (let attribute in initialState.attributes)
	snapshot.attributes[attribute] = lastSnapshot.element[attribute];

	startIndex = lastSnapshot.index;
	}

	applyActions(startIndex, snapshot.index - 1);
	if (snapshot.index > 0)
	snapshot.states = actions[snapshot.index - 1].states;

	snapshot.content = new Image;
	snapshot.content.src = snapshot.element.toDataURL();
	snapshot.content.addEventListener("load", imageLoad);
	return;
	}

	this._previewContainer.removeChildren();

	if (showCanvasPath) {
	indexOfLastBeginPathAction = this._index;
	while (indexOfLastBeginPathAction > snapshot.index && actions[indexOfLastBeginPathAction].name !== "beginPath")
	--indexOfLastBeginPathAction;
	}

	applyActions(snapshot.index, this._index);

	this._previewContainer.insertAdjacentElement("afterbegin", snapshot.element);
	this._updateImageGrid();
	}

	_generateContentFromSnapshot(index)
	{
	let imageLoad = (event) => {
	// Loading took too long and the current action index has already changed.
	if (index !== this._index)
	return;

	this._generateContentFromSnapshot(index);
	};

	let initialState = this.representedObject.initialState;
	if (initialState.content && !this._initialContent) {
	this._initialContent = new Image;
	this._initialContent.src = initialState.content;
	this._initialContent.addEventListener("load", imageLoad);
	return;
	}

	let actions = this.representedObject.actions;

	let visualIndex = index;
	while (!actions[visualIndex].isVisual && !(actions[visualIndex] instanceof WI.RecordingInitialStateAction))
	visualIndex--;

	let snapshot = this._snapshots[visualIndex];
	if (!snapshot) {
	if (actions[visualIndex].snapshot) {
	snapshot = this._snapshots[visualIndex] = {element: new Image};
	snapshot.element.src = actions[visualIndex].snapshot;
	snapshot.element.addEventListener("load", imageLoad);
	return;
	}

	if (actions[visualIndex] instanceof WI.RecordingInitialStateAction)
	snapshot = this._snapshots[visualIndex] = {element: this._initialContent};
	}

	if (snapshot) {
	this._previewContainer.removeChildren();
	this._previewContainer.appendChild(snapshot.element);

	this._updateImageGrid();
	}
	}

	_updateExportButton()
	{
	if (this.representedObject.type === WI.Recording.Type.Canvas2D && this.representedObject.ready)
	this._exportButtonNavigationItem.tooltip = WI.UIString("Export recording (%s)\nShift-click to export a HTML reduction").format(WI.saveKeyboardShortcut.displayName);
	else
	this._exportButtonNavigationItem.tooltip = WI.UIString("Export recording (%s)").format(WI.saveKeyboardShortcut.displayName);
	}

	_updateCanvasPath()
	{
	let activated = WI.settings.showCanvasPath.value;

	if (this._showPathButtonNavigationItem.activated !== activated)
	this._generateContentCanvas2D(this._index);

	this._showPathButtonNavigationItem.activated = activated;
	}

	_updateImageGrid()
	{
	let activated = WI.settings.showImageGrid.value;
	this._showGridButtonNavigationItem.activated = activated;

	if (this.didInitialLayout && !isNaN(this._index))
	this._previewContainer.firstElementChild.classList.toggle("show-grid", activated);
	}

	_updateSliderValue()
	{
	if (!this._sliderElement)
	return;

	let visualActionIndexes = this.representedObject.visualActionIndexes;
	let visualActionIndex = 0;
	if (this._index > 0) {
	while (visualActionIndex < visualActionIndexes.length && visualActionIndexes[visualActionIndex] <= this._index)
	visualActionIndex++;
	}

	this._sliderElement.value = visualActionIndex;
	this._sliderValueElement.textContent = WI.UIString("%d of %d").format(visualActionIndex, visualActionIndexes.length);
	}

	_showPathButtonClicked(event)
	{
	WI.settings.showCanvasPath.value = !this._showPathButtonNavigationItem.activated;

	this._updateCanvasPath();
	}

	_showGridButtonClicked(event)
	{
	WI.settings.showImageGrid.value = !this._showGridButtonNavigationItem.activated;

	this._updateImageGrid();
	}

	_handleExportNavigationItemClicked(event)
	{
	if (event.data.nativeEvent.shiftKey && this.representedObject.type === WI.Recording.Type.Canvas2D && this.representedObject.ready)
	this._exportReduction();
	else
	this._exportRecording();
	}

	_sliderChanged()
	{
	let index = 0;

	let visualActionIndex = parseInt(this._sliderElement.value) - 1;
	if (visualActionIndex !== -1)
	index = this.representedObject.visualActionIndexes[visualActionIndex];

	this.updateActionIndex(index);
	}

	_handleRecordingProcessedAction(event)
	{
	this._updateExportButton();

	this._sliderElement.max = this.representedObject.visualActionIndexes.length;
	this._updateSliderValue();

	if (this.representedObject.ready)
	this.representedObject.removeEventListener(null, null, this);
	}
	};

	WI.RecordingContentView.SnapshotInterval = 5000;