src/cobalt/debug/devtools/front_end/animation/AnimationUI.js - cobalt - Git at Google

 // Copyright (c) 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 /**
  * @unrestricted
  */
 Animation.AnimationUI = class {
   /**
    * @param {!Animation.AnimationModel.Animation} animation
    * @param {!Animation.AnimationTimeline} timeline
    * @param {!Element} parentElement
    */
   constructor(animation, timeline, parentElement) {
     this._animation = animation;
     this._timeline = timeline;
     this._parentElement = parentElement;

     if (this._animation.source().keyframesRule())
       this._keyframes = this._animation.source().keyframesRule().keyframes();

     this._nameElement = parentElement.createChild('div', 'animation-name');
     this._nameElement.textContent = this._animation.name();

     this._svg = parentElement.createSVGChild('svg', 'animation-ui');
     this._svg.setAttribute('height', Animation.AnimationUI.Options.AnimationSVGHeight);
     this._svg.style.marginLeft = '-' + Animation.AnimationUI.Options.AnimationMargin + 'px';
     this._svg.addEventListener('contextmenu', this._onContextMenu.bind(this));
     this._activeIntervalGroup = this._svg.createSVGChild('g');
     UI.installDragHandle(
         this._activeIntervalGroup, this._mouseDown.bind(this, Animation.AnimationUI.MouseEvents.AnimationDrag, null),
         this._mouseMove.bind(this), this._mouseUp.bind(this), '-webkit-grabbing', '-webkit-grab');

     /** @type {!Array.<{group: ?Element, animationLine: ?Element, keyframePoints: !Object.<number, !Element>, keyframeRender: !Object.<number, !Element>}>} */
     this._cachedElements = [];

     this._movementInMs = 0;
     this._color = Animation.AnimationUI.Color(this._animation);
   }

   /**
    * @param {!Animation.AnimationModel.Animation} animation
    * @return {string}
    */
   static Color(animation) {
     const names = Object.keys(Animation.AnimationUI.Colors);
     const color =
         Animation.AnimationUI.Colors[names[String.hashCode(animation.name() || animation.id()) % names.length]];
     return color.asString(Common.Color.Format.RGB);
   }

   /**
    * @return {!Animation.AnimationModel.Animation}
    */
   animation() {
     return this._animation;
   }

   /**
    * @param {?SDK.DOMNode} node
    */
   setNode(node) {
     this._node = node;
   }

   /**
    * @param {!Element} parentElement
    * @param {string} className
    */
   _createLine(parentElement, className) {
     const line = parentElement.createSVGChild('line', className);
     line.setAttribute('x1', Animation.AnimationUI.Options.AnimationMargin);
     line.setAttribute('y1', Animation.AnimationUI.Options.AnimationHeight);
     line.setAttribute('y2', Animation.AnimationUI.Options.AnimationHeight);
     line.style.stroke = this._color;
     return line;
   }

   /**
    * @param {number} iteration
    * @param {!Element} parentElement
    */
   _drawAnimationLine(iteration, parentElement) {
     const cache = this._cachedElements[iteration];
     if (!cache.animationLine)
       cache.animationLine = this._createLine(parentElement, 'animation-line');
     cache.animationLine.setAttribute(
         'x2',
         (this._duration() * this._timeline.pixelMsRatio() + Animation.AnimationUI.Options.AnimationMargin).toFixed(2));
   }

   /**
    * @param {!Element} parentElement
    */
   _drawDelayLine(parentElement) {
     if (!this._delayLine) {
       this._delayLine = this._createLine(parentElement, 'animation-delay-line');
       this._endDelayLine = this._createLine(parentElement, 'animation-delay-line');
     }
     const fill = this._animation.source().fill();
     this._delayLine.classList.toggle('animation-fill', fill === 'backwards' || fill === 'both');
     const margin = Animation.AnimationUI.Options.AnimationMargin;
     this._delayLine.setAttribute('x1', margin);
     this._delayLine.setAttribute('x2', (this._delay() * this._timeline.pixelMsRatio() + margin).toFixed(2));
     const forwardsFill = fill === 'forwards' || fill === 'both';
     this._endDelayLine.classList.toggle('animation-fill', forwardsFill);
     const leftMargin = Math.min(
         this._timeline.width(),
         (this._delay() + this._duration() * this._animation.source().iterations()) * this._timeline.pixelMsRatio());
     this._endDelayLine.style.transform = 'translateX(' + leftMargin.toFixed(2) + 'px)';
     this._endDelayLine.setAttribute('x1', margin);
     this._endDelayLine.setAttribute(
         'x2', forwardsFill ? (this._timeline.width() - leftMargin + margin).toFixed(2) :
                              (this._animation.source().endDelay() * this._timeline.pixelMsRatio() + margin).toFixed(2));
   }

   /**
    * @param {number} iteration
    * @param {!Element} parentElement
    * @param {number} x
    * @param {number} keyframeIndex
    * @param {boolean} attachEvents
    */
   _drawPoint(iteration, parentElement, x, keyframeIndex, attachEvents) {
     if (this._cachedElements[iteration].keyframePoints[keyframeIndex]) {
       this._cachedElements[iteration].keyframePoints[keyframeIndex].setAttribute('cx', x.toFixed(2));
       return;
     }

     const circle =
         parentElement.createSVGChild('circle', keyframeIndex <= 0 ? 'animation-endpoint' : 'animation-keyframe-point');
     circle.setAttribute('cx', x.toFixed(2));
     circle.setAttribute('cy', Animation.AnimationUI.Options.AnimationHeight);
     circle.style.stroke = this._color;
     circle.setAttribute('r', Animation.AnimationUI.Options.AnimationMargin / 2);

     if (keyframeIndex <= 0)
       circle.style.fill = this._color;

     this._cachedElements[iteration].keyframePoints[keyframeIndex] = circle;

     if (!attachEvents)
       return;

     let eventType;
     if (keyframeIndex === 0)
       eventType = Animation.AnimationUI.MouseEvents.StartEndpointMove;
     else if (keyframeIndex === -1)
       eventType = Animation.AnimationUI.MouseEvents.FinishEndpointMove;
     else
       eventType = Animation.AnimationUI.MouseEvents.KeyframeMove;
     UI.installDragHandle(
         circle, this._mouseDown.bind(this, eventType, keyframeIndex), this._mouseMove.bind(this),
         this._mouseUp.bind(this), 'ew-resize');
   }

   /**
    * @param {number} iteration
    * @param {number} keyframeIndex
    * @param {!Element} parentElement
    * @param {number} leftDistance
    * @param {number} width
    * @param {string} easing
    */
   _renderKeyframe(iteration, keyframeIndex, parentElement, leftDistance, width, easing) {
     /**
      * @param {!Element} parentElement
      * @param {number} x
      * @param {string} strokeColor
      */
     function createStepLine(parentElement, x, strokeColor) {
       const line = parentElement.createSVGChild('line');
       line.setAttribute('x1', x);
       line.setAttribute('x2', x);
       line.setAttribute('y1', Animation.AnimationUI.Options.AnimationMargin);
       line.setAttribute('y2', Animation.AnimationUI.Options.AnimationHeight);
       line.style.stroke = strokeColor;
     }

     const bezier = UI.Geometry.CubicBezier.parse(easing);
     const cache = this._cachedElements[iteration].keyframeRender;
     if (!cache[keyframeIndex]) {
       cache[keyframeIndex] = bezier ? parentElement.createSVGChild('path', 'animation-keyframe') :
                                       parentElement.createSVGChild('g', 'animation-keyframe-step');
     }
     const group = cache[keyframeIndex];
     group.style.transform = 'translateX(' + leftDistance.toFixed(2) + 'px)';

     if (easing === 'linear') {
       group.style.fill = this._color;
       const height = InlineEditor.BezierUI.Height;
       group.setAttribute(
           'd', ['M', 0, height, 'L', 0, 5, 'L', width.toFixed(2), 5, 'L', width.toFixed(2), height, 'Z'].join(' '));
     } else if (bezier) {
       group.style.fill = this._color;
       InlineEditor.BezierUI.drawVelocityChart(bezier, group, width);
     } else {
       const stepFunction = Animation.AnimationTimeline.StepTimingFunction.parse(easing);
       group.removeChildren();
       /** @const */ const offsetMap = {'start': 0, 'middle': 0.5, 'end': 1};
       /** @const */ const offsetWeight = offsetMap[stepFunction.stepAtPosition];
       for (let i = 0; i < stepFunction.steps; i++)
         createStepLine(group, (i + offsetWeight) * width / stepFunction.steps, this._color);
     }
   }

   redraw() {
     const maxWidth = this._timeline.width() - Animation.AnimationUI.Options.AnimationMargin;

     this._svg.setAttribute('width', (maxWidth + 2 * Animation.AnimationUI.Options.AnimationMargin).toFixed(2));
     this._activeIntervalGroup.style.transform =
         'translateX(' + (this._delay() * this._timeline.pixelMsRatio()).toFixed(2) + 'px)';

     this._nameElement.style.transform = 'translateX(' +
         (this._delay() * this._timeline.pixelMsRatio() + Animation.AnimationUI.Options.AnimationMargin).toFixed(2) +
         'px)';
     this._nameElement.style.width = (this._duration() * this._timeline.pixelMsRatio()).toFixed(2) + 'px';
     this._drawDelayLine(this._svg);

     if (this._animation.type() === 'CSSTransition') {
       this._renderTransition();
       return;
     }

     this._renderIteration(this._activeIntervalGroup, 0);
     if (!this._tailGroup)
       this._tailGroup = this._activeIntervalGroup.createSVGChild('g', 'animation-tail-iterations');
     const iterationWidth = this._duration() * this._timeline.pixelMsRatio();
     let iteration;
     for (iteration = 1;
          iteration < this._animation.source().iterations() && iterationWidth * (iteration - 1) < this._timeline.width();
          iteration++)
       this._renderIteration(this._tailGroup, iteration);
     while (iteration < this._cachedElements.length)
       this._cachedElements.pop().group.remove();
   }

   _renderTransition() {
     if (!this._cachedElements[0])
       this._cachedElements[0] = {animationLine: null, keyframePoints: {}, keyframeRender: {}, group: null};
     this._drawAnimationLine(0, this._activeIntervalGroup);
     this._renderKeyframe(
         0, 0, this._activeIntervalGroup, Animation.AnimationUI.Options.AnimationMargin,
         this._duration() * this._timeline.pixelMsRatio(), this._animation.source().easing());
     this._drawPoint(0, this._activeIntervalGroup, Animation.AnimationUI.Options.AnimationMargin, 0, true);
     this._drawPoint(
         0, this._activeIntervalGroup,
         this._duration() * this._timeline.pixelMsRatio() + Animation.AnimationUI.Options.AnimationMargin, -1, true);
   }

   /**
    * @param {!Element} parentElement
    * @param {number} iteration
    */
   _renderIteration(parentElement, iteration) {
     if (!this._cachedElements[iteration]) {
       this._cachedElements[iteration] =
           {animationLine: null, keyframePoints: {}, keyframeRender: {}, group: parentElement.createSVGChild('g')};
     }
     const group = this._cachedElements[iteration].group;
     group.style.transform =
         'translateX(' + (iteration * this._duration() * this._timeline.pixelMsRatio()).toFixed(2) + 'px)';
     this._drawAnimationLine(iteration, group);
     console.assert(this._keyframes.length > 1);
     for (let i = 0; i < this._keyframes.length - 1; i++) {
       const leftDistance = this._offset(i) * this._duration() * this._timeline.pixelMsRatio() +
           Animation.AnimationUI.Options.AnimationMargin;
       const width = this._duration() * (this._offset(i + 1) - this._offset(i)) * this._timeline.pixelMsRatio();
       this._renderKeyframe(iteration, i, group, leftDistance, width, this._keyframes[i].easing());
       if (i || (!i && iteration === 0))
         this._drawPoint(iteration, group, leftDistance, i, iteration === 0);
     }
     this._drawPoint(
         iteration, group,
         this._duration() * this._timeline.pixelMsRatio() + Animation.AnimationUI.Options.AnimationMargin, -1,
         iteration === 0);
   }

   /**
    * @return {number}
    */
   _delay() {
     let delay = this._animation.source().delay();
     if (this._mouseEventType === Animation.AnimationUI.MouseEvents.AnimationDrag ||
         this._mouseEventType === Animation.AnimationUI.MouseEvents.StartEndpointMove)
       delay += this._movementInMs;
     // FIXME: add support for negative start delay
     return Math.max(0, delay);
   }

   /**
    * @return {number}
    */
   _duration() {
     let duration = this._animation.source().duration();
     if (this._mouseEventType === Animation.AnimationUI.MouseEvents.FinishEndpointMove)
       duration += this._movementInMs;
     else if (this._mouseEventType === Animation.AnimationUI.MouseEvents.StartEndpointMove)
       duration -= Math.max(this._movementInMs, -this._animation.source().delay());  // Cannot have negative delay
     return Math.max(0, duration);
   }

   /**
    * @param {number} i
    * @return {number} offset
    */
   _offset(i) {
     let offset = this._keyframes[i].offsetAsNumber();
     if (this._mouseEventType === Animation.AnimationUI.MouseEvents.KeyframeMove && i === this._keyframeMoved) {
       console.assert(i > 0 && i < this._keyframes.length - 1, 'First and last keyframe cannot be moved');
       offset += this._movementInMs / this._animation.source().duration();
       offset = Math.max(offset, this._keyframes[i - 1].offsetAsNumber());
       offset = Math.min(offset, this._keyframes[i + 1].offsetAsNumber());
     }
     return offset;
   }

   /**
    * @param {!Animation.AnimationUI.MouseEvents} mouseEventType
    * @param {?number} keyframeIndex
    * @param {!Event} event
    */
   _mouseDown(mouseEventType, keyframeIndex, event) {
     if (event.buttons === 2)
       return false;
     if (this._svg.enclosingNodeOrSelfWithClass('animation-node-removed'))
       return false;
     this._mouseEventType = mouseEventType;
     this._keyframeMoved = keyframeIndex;
     this._downMouseX = event.clientX;
     event.consume(true);
     if (this._node)
       Common.Revealer.reveal(this._node);
     return true;
   }

   /**
    * @param {!Event} event
    */
   _mouseMove(event) {
     this._movementInMs = (event.clientX - this._downMouseX) / this._timeline.pixelMsRatio();
     if (this._delay() + this._duration() > this._timeline.duration() * 0.8)
       this._timeline.setDuration(this._timeline.duration() * 1.2);
     this.redraw();
   }

   /**
    * @param {!Event} event
    */
   _mouseUp(event) {
     this._movementInMs = (event.clientX - this._downMouseX) / this._timeline.pixelMsRatio();

     // Commit changes
     if (this._mouseEventType === Animation.AnimationUI.MouseEvents.KeyframeMove)
       this._keyframes[this._keyframeMoved].setOffset(this._offset(this._keyframeMoved));
     else
       this._animation.setTiming(this._duration(), this._delay());

     this._movementInMs = 0;
     this.redraw();

     delete this._mouseEventType;
     delete this._downMouseX;
     delete this._keyframeMoved;
   }

   /**
    * @param {!Event} event
    */
   _onContextMenu(event) {
     /**
      * @param {?SDK.RemoteObject} remoteObject
      */
     function showContextMenu(remoteObject) {
       if (!remoteObject)
         return;
       const contextMenu = new UI.ContextMenu(event);
       contextMenu.appendApplicableItems(remoteObject);
       contextMenu.show();
     }

     this._animation.remoteObjectPromise().then(showContextMenu);
     event.consume(true);
   }
 };

 /**
  * @enum {string}
  */
 Animation.AnimationUI.MouseEvents = {
   AnimationDrag: 'AnimationDrag',
   KeyframeMove: 'KeyframeMove',
   StartEndpointMove: 'StartEndpointMove',
   FinishEndpointMove: 'FinishEndpointMove'
 };

 Animation.AnimationUI.Options = {
   AnimationHeight: 26,
   AnimationSVGHeight: 50,
   AnimationMargin: 7,
   EndpointsClickRegionSize: 10,
   GridCanvasHeight: 40
 };

 Animation.AnimationUI.Colors = {
   'Purple': Common.Color.parse('#9C27B0'),
   'Light Blue': Common.Color.parse('#03A9F4'),
   'Deep Orange': Common.Color.parse('#FF5722'),
   'Blue': Common.Color.parse('#5677FC'),
   'Lime': Common.Color.parse('#CDDC39'),
   'Blue Grey': Common.Color.parse('#607D8B'),
   'Pink': Common.Color.parse('#E91E63'),
   'Green': Common.Color.parse('#0F9D58'),
   'Brown': Common.Color.parse('#795548'),
   'Cyan': Common.Color.parse('#00BCD4')
 };
	// Copyright (c) 2015 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.
	/**
	* @unrestricted
	*/
	Animation.AnimationUI = class {
	/**
	* @param {!Animation.AnimationModel.Animation} animation
	* @param {!Animation.AnimationTimeline} timeline
	* @param {!Element} parentElement
	*/
	constructor(animation, timeline, parentElement) {
	this._animation = animation;
	this._timeline = timeline;
	this._parentElement = parentElement;

	if (this._animation.source().keyframesRule())
	this._keyframes = this._animation.source().keyframesRule().keyframes();

	this._nameElement = parentElement.createChild('div', 'animation-name');
	this._nameElement.textContent = this._animation.name();

	this._svg = parentElement.createSVGChild('svg', 'animation-ui');
	this._svg.setAttribute('height', Animation.AnimationUI.Options.AnimationSVGHeight);
	this._svg.style.marginLeft = '-' + Animation.AnimationUI.Options.AnimationMargin + 'px';
	this._svg.addEventListener('contextmenu', this._onContextMenu.bind(this));
	this._activeIntervalGroup = this._svg.createSVGChild('g');
	UI.installDragHandle(
	this._activeIntervalGroup, this._mouseDown.bind(this, Animation.AnimationUI.MouseEvents.AnimationDrag, null),
	this._mouseMove.bind(this), this._mouseUp.bind(this), '-webkit-grabbing', '-webkit-grab');

	/** @type {!Array.<{group: ?Element, animationLine: ?Element, keyframePoints: !Object.<number, !Element>, keyframeRender: !Object.<number, !Element>}>} */
	this._cachedElements = [];

	this._movementInMs = 0;
	this._color = Animation.AnimationUI.Color(this._animation);
	}

	/**
	* @param {!Animation.AnimationModel.Animation} animation
	* @return {string}
	*/
	static Color(animation) {
	const names = Object.keys(Animation.AnimationUI.Colors);
	const color =
	Animation.AnimationUI.Colors[names[String.hashCode(animation.name() \|\| animation.id()) % names.length]];
	return color.asString(Common.Color.Format.RGB);
	}

	/**
	* @return {!Animation.AnimationModel.Animation}
	*/
	animation() {
	return this._animation;
	}

	/**
	* @param {?SDK.DOMNode} node
	*/
	setNode(node) {
	this._node = node;
	}

	/**
	* @param {!Element} parentElement
	* @param {string} className
	*/
	_createLine(parentElement, className) {
	const line = parentElement.createSVGChild('line', className);
	line.setAttribute('x1', Animation.AnimationUI.Options.AnimationMargin);
	line.setAttribute('y1', Animation.AnimationUI.Options.AnimationHeight);
	line.setAttribute('y2', Animation.AnimationUI.Options.AnimationHeight);
	line.style.stroke = this._color;
	return line;
	}

	/**
	* @param {number} iteration
	* @param {!Element} parentElement
	*/
	_drawAnimationLine(iteration, parentElement) {
	const cache = this._cachedElements[iteration];
	if (!cache.animationLine)
	cache.animationLine = this._createLine(parentElement, 'animation-line');
	cache.animationLine.setAttribute(
	'x2',
	(this._duration() * this._timeline.pixelMsRatio() + Animation.AnimationUI.Options.AnimationMargin).toFixed(2));
	}

	/**
	* @param {!Element} parentElement
	*/
	_drawDelayLine(parentElement) {
	if (!this._delayLine) {
	this._delayLine = this._createLine(parentElement, 'animation-delay-line');
	this._endDelayLine = this._createLine(parentElement, 'animation-delay-line');
	}
	const fill = this._animation.source().fill();
	this._delayLine.classList.toggle('animation-fill', fill === 'backwards' \|\| fill === 'both');
	const margin = Animation.AnimationUI.Options.AnimationMargin;
	this._delayLine.setAttribute('x1', margin);
	this._delayLine.setAttribute('x2', (this._delay() * this._timeline.pixelMsRatio() + margin).toFixed(2));
	const forwardsFill = fill === 'forwards' \|\| fill === 'both';
	this._endDelayLine.classList.toggle('animation-fill', forwardsFill);
	const leftMargin = Math.min(
	this._timeline.width(),
	(this._delay() + this._duration() * this._animation.source().iterations()) * this._timeline.pixelMsRatio());
	this._endDelayLine.style.transform = 'translateX(' + leftMargin.toFixed(2) + 'px)';
	this._endDelayLine.setAttribute('x1', margin);
	this._endDelayLine.setAttribute(
	'x2', forwardsFill ? (this._timeline.width() - leftMargin + margin).toFixed(2) :
	(this._animation.source().endDelay() * this._timeline.pixelMsRatio() + margin).toFixed(2));
	}

	/**
	* @param {number} iteration
	* @param {!Element} parentElement
	* @param {number} x
	* @param {number} keyframeIndex
	* @param {boolean} attachEvents
	*/
	_drawPoint(iteration, parentElement, x, keyframeIndex, attachEvents) {
	if (this._cachedElements[iteration].keyframePoints[keyframeIndex]) {
	this._cachedElements[iteration].keyframePoints[keyframeIndex].setAttribute('cx', x.toFixed(2));
	return;
	}

	const circle =
	parentElement.createSVGChild('circle', keyframeIndex <= 0 ? 'animation-endpoint' : 'animation-keyframe-point');
	circle.setAttribute('cx', x.toFixed(2));
	circle.setAttribute('cy', Animation.AnimationUI.Options.AnimationHeight);
	circle.style.stroke = this._color;
	circle.setAttribute('r', Animation.AnimationUI.Options.AnimationMargin / 2);

	if (keyframeIndex <= 0)
	circle.style.fill = this._color;

	this._cachedElements[iteration].keyframePoints[keyframeIndex] = circle;

	if (!attachEvents)
	return;

	let eventType;
	if (keyframeIndex === 0)
	eventType = Animation.AnimationUI.MouseEvents.StartEndpointMove;
	else if (keyframeIndex === -1)
	eventType = Animation.AnimationUI.MouseEvents.FinishEndpointMove;
	else
	eventType = Animation.AnimationUI.MouseEvents.KeyframeMove;
	UI.installDragHandle(
	circle, this._mouseDown.bind(this, eventType, keyframeIndex), this._mouseMove.bind(this),
	this._mouseUp.bind(this), 'ew-resize');
	}

	/**
	* @param {number} iteration
	* @param {number} keyframeIndex
	* @param {!Element} parentElement
	* @param {number} leftDistance
	* @param {number} width
	* @param {string} easing
	*/
	_renderKeyframe(iteration, keyframeIndex, parentElement, leftDistance, width, easing) {
	/**
	* @param {!Element} parentElement
	* @param {number} x
	* @param {string} strokeColor
	*/
	function createStepLine(parentElement, x, strokeColor) {
	const line = parentElement.createSVGChild('line');
	line.setAttribute('x1', x);
	line.setAttribute('x2', x);
	line.setAttribute('y1', Animation.AnimationUI.Options.AnimationMargin);
	line.setAttribute('y2', Animation.AnimationUI.Options.AnimationHeight);
	line.style.stroke = strokeColor;
	}

	const bezier = UI.Geometry.CubicBezier.parse(easing);
	const cache = this._cachedElements[iteration].keyframeRender;
	if (!cache[keyframeIndex]) {
	cache[keyframeIndex] = bezier ? parentElement.createSVGChild('path', 'animation-keyframe') :
	parentElement.createSVGChild('g', 'animation-keyframe-step');
	}
	const group = cache[keyframeIndex];
	group.style.transform = 'translateX(' + leftDistance.toFixed(2) + 'px)';

	if (easing === 'linear') {
	group.style.fill = this._color;
	const height = InlineEditor.BezierUI.Height;
	group.setAttribute(
	'd', ['M', 0, height, 'L', 0, 5, 'L', width.toFixed(2), 5, 'L', width.toFixed(2), height, 'Z'].join(' '));
	} else if (bezier) {
	group.style.fill = this._color;
	InlineEditor.BezierUI.drawVelocityChart(bezier, group, width);
	} else {
	const stepFunction = Animation.AnimationTimeline.StepTimingFunction.parse(easing);
	group.removeChildren();
	/** @const */ const offsetMap = {'start': 0, 'middle': 0.5, 'end': 1};
	/** @const */ const offsetWeight = offsetMap[stepFunction.stepAtPosition];
	for (let i = 0; i < stepFunction.steps; i++)
	createStepLine(group, (i + offsetWeight) * width / stepFunction.steps, this._color);
	}
	}

	redraw() {
	const maxWidth = this._timeline.width() - Animation.AnimationUI.Options.AnimationMargin;

	this._svg.setAttribute('width', (maxWidth + 2 * Animation.AnimationUI.Options.AnimationMargin).toFixed(2));
	this._activeIntervalGroup.style.transform =
	'translateX(' + (this._delay() * this._timeline.pixelMsRatio()).toFixed(2) + 'px)';

	this._nameElement.style.transform = 'translateX(' +
	(this._delay() * this._timeline.pixelMsRatio() + Animation.AnimationUI.Options.AnimationMargin).toFixed(2) +
	'px)';
	this._nameElement.style.width = (this._duration() * this._timeline.pixelMsRatio()).toFixed(2) + 'px';
	this._drawDelayLine(this._svg);

	if (this._animation.type() === 'CSSTransition') {
	this._renderTransition();
	return;
	}

	this._renderIteration(this._activeIntervalGroup, 0);
	if (!this._tailGroup)
	this._tailGroup = this._activeIntervalGroup.createSVGChild('g', 'animation-tail-iterations');
	const iterationWidth = this._duration() * this._timeline.pixelMsRatio();
	let iteration;
	for (iteration = 1;
	iteration < this._animation.source().iterations() && iterationWidth * (iteration - 1) < this._timeline.width();
	iteration++)
	this._renderIteration(this._tailGroup, iteration);
	while (iteration < this._cachedElements.length)
	this._cachedElements.pop().group.remove();
	}

	_renderTransition() {
	if (!this._cachedElements[0])
	this._cachedElements[0] = {animationLine: null, keyframePoints: {}, keyframeRender: {}, group: null};
	this._drawAnimationLine(0, this._activeIntervalGroup);
	this._renderKeyframe(
	0, 0, this._activeIntervalGroup, Animation.AnimationUI.Options.AnimationMargin,
	this._duration() * this._timeline.pixelMsRatio(), this._animation.source().easing());
	this._drawPoint(0, this._activeIntervalGroup, Animation.AnimationUI.Options.AnimationMargin, 0, true);
	this._drawPoint(
	0, this._activeIntervalGroup,
	this._duration() * this._timeline.pixelMsRatio() + Animation.AnimationUI.Options.AnimationMargin, -1, true);
	}

	/**
	* @param {!Element} parentElement
	* @param {number} iteration
	*/
	_renderIteration(parentElement, iteration) {
	if (!this._cachedElements[iteration]) {
	this._cachedElements[iteration] =
	{animationLine: null, keyframePoints: {}, keyframeRender: {}, group: parentElement.createSVGChild('g')};
	}
	const group = this._cachedElements[iteration].group;
	group.style.transform =
	'translateX(' + (iteration * this._duration() * this._timeline.pixelMsRatio()).toFixed(2) + 'px)';
	this._drawAnimationLine(iteration, group);
	console.assert(this._keyframes.length > 1);
	for (let i = 0; i < this._keyframes.length - 1; i++) {
	const leftDistance = this._offset(i) * this._duration() * this._timeline.pixelMsRatio() +
	Animation.AnimationUI.Options.AnimationMargin;
	const width = this._duration() * (this._offset(i + 1) - this._offset(i)) * this._timeline.pixelMsRatio();
	this._renderKeyframe(iteration, i, group, leftDistance, width, this._keyframes[i].easing());
	if (i \|\| (!i && iteration === 0))
	this._drawPoint(iteration, group, leftDistance, i, iteration === 0);
	}
	this._drawPoint(
	iteration, group,
	this._duration() * this._timeline.pixelMsRatio() + Animation.AnimationUI.Options.AnimationMargin, -1,
	iteration === 0);
	}

	/**
	* @return {number}
	*/
	_delay() {
	let delay = this._animation.source().delay();
	if (this._mouseEventType === Animation.AnimationUI.MouseEvents.AnimationDrag \|\|
	this._mouseEventType === Animation.AnimationUI.MouseEvents.StartEndpointMove)
	delay += this._movementInMs;
	// FIXME: add support for negative start delay
	return Math.max(0, delay);
	}

	/**
	* @return {number}
	*/
	_duration() {
	let duration = this._animation.source().duration();
	if (this._mouseEventType === Animation.AnimationUI.MouseEvents.FinishEndpointMove)
	duration += this._movementInMs;
	else if (this._mouseEventType === Animation.AnimationUI.MouseEvents.StartEndpointMove)
	duration -= Math.max(this._movementInMs, -this._animation.source().delay()); // Cannot have negative delay
	return Math.max(0, duration);
	}

	/**
	* @param {number} i
	* @return {number} offset
	*/
	_offset(i) {
	let offset = this._keyframes[i].offsetAsNumber();
	if (this._mouseEventType === Animation.AnimationUI.MouseEvents.KeyframeMove && i === this._keyframeMoved) {
	console.assert(i > 0 && i < this._keyframes.length - 1, 'First and last keyframe cannot be moved');
	offset += this._movementInMs / this._animation.source().duration();
	offset = Math.max(offset, this._keyframes[i - 1].offsetAsNumber());
	offset = Math.min(offset, this._keyframes[i + 1].offsetAsNumber());
	}
	return offset;
	}

	/**
	* @param {!Animation.AnimationUI.MouseEvents} mouseEventType
	* @param {?number} keyframeIndex
	* @param {!Event} event
	*/
	_mouseDown(mouseEventType, keyframeIndex, event) {
	if (event.buttons === 2)
	return false;
	if (this._svg.enclosingNodeOrSelfWithClass('animation-node-removed'))
	return false;
	this._mouseEventType = mouseEventType;
	this._keyframeMoved = keyframeIndex;
	this._downMouseX = event.clientX;
	event.consume(true);
	if (this._node)
	Common.Revealer.reveal(this._node);
	return true;
	}

	/**
	* @param {!Event} event
	*/
	_mouseMove(event) {
	this._movementInMs = (event.clientX - this._downMouseX) / this._timeline.pixelMsRatio();
	if (this._delay() + this._duration() > this._timeline.duration() * 0.8)
	this._timeline.setDuration(this._timeline.duration() * 1.2);
	this.redraw();
	}

	/**
	* @param {!Event} event
	*/
	_mouseUp(event) {
	this._movementInMs = (event.clientX - this._downMouseX) / this._timeline.pixelMsRatio();

	// Commit changes
	if (this._mouseEventType === Animation.AnimationUI.MouseEvents.KeyframeMove)
	this._keyframes[this._keyframeMoved].setOffset(this._offset(this._keyframeMoved));
	else
	this._animation.setTiming(this._duration(), this._delay());

	this._movementInMs = 0;
	this.redraw();

	delete this._mouseEventType;
	delete this._downMouseX;
	delete this._keyframeMoved;
	}

	/**
	* @param {!Event} event
	*/
	_onContextMenu(event) {
	/**
	* @param {?SDK.RemoteObject} remoteObject
	*/
	function showContextMenu(remoteObject) {
	if (!remoteObject)
	return;
	const contextMenu = new UI.ContextMenu(event);
	contextMenu.appendApplicableItems(remoteObject);
	contextMenu.show();
	}

	this._animation.remoteObjectPromise().then(showContextMenu);
	event.consume(true);
	}
	};

	/**
	* @enum {string}
	*/
	Animation.AnimationUI.MouseEvents = {
	AnimationDrag: 'AnimationDrag',
	KeyframeMove: 'KeyframeMove',
	StartEndpointMove: 'StartEndpointMove',
	FinishEndpointMove: 'FinishEndpointMove'
	};

	Animation.AnimationUI.Options = {
	AnimationHeight: 26,
	AnimationSVGHeight: 50,
	AnimationMargin: 7,
	EndpointsClickRegionSize: 10,
	GridCanvasHeight: 40
	};

	Animation.AnimationUI.Colors = {
	'Purple': Common.Color.parse('#9C27B0'),
	'Light Blue': Common.Color.parse('#03A9F4'),
	'Deep Orange': Common.Color.parse('#FF5722'),
	'Blue': Common.Color.parse('#5677FC'),
	'Lime': Common.Color.parse('#CDDC39'),
	'Blue Grey': Common.Color.parse('#607D8B'),
	'Pink': Common.Color.parse('#E91E63'),
	'Green': Common.Color.parse('#0F9D58'),
	'Brown': Common.Color.parse('#795548'),
	'Cyan': Common.Color.parse('#00BCD4')
	};