Add m-esr52 at 52.6.0

1 files changed, 897 insertions, 0 deletions

diff --git a/devtools/client/shared/widgets/CubicBezierWidget.js b/devtools/client/shared/widgets/CubicBezierWidget.js
new file mode 100644
index 000000000..337282d46
--- /dev/null
+++ b/devtools/client/shared/widgets/CubicBezierWidget.js
@@ -0,0 +1,897 @@
+/**
+ * Copyright (c) 2013 Lea Verou. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+// Based on www.cubic-bezier.com by Lea Verou
+// See https://github.com/LeaVerou/cubic-bezier
+
+"use strict";
+
+const EventEmitter = require("devtools/shared/event-emitter");
+const {
+  PREDEFINED,
+  PRESETS,
+  DEFAULT_PRESET_CATEGORY
+} = require("devtools/client/shared/widgets/CubicBezierPresets");
+const {getCSSLexer} = require("devtools/shared/css/lexer");
+const XHTML_NS = "http://www.w3.org/1999/xhtml";
+
+/**
+ * CubicBezier data structure helper
+ * Accepts an array of coordinates and exposes a few useful getters
+ * @param {Array} coordinates i.e. [.42, 0, .58, 1]
+ */
+function CubicBezier(coordinates) {
+  if (!coordinates) {
+    throw new Error("No offsets were defined");
+  }
+
+  this.coordinates = coordinates.map(n => +n);
+
+  for (let i = 4; i--;) {
+    let xy = this.coordinates[i];
+    if (isNaN(xy) || (!(i % 2) && (xy < 0 || xy > 1))) {
+      throw new Error(`Wrong coordinate at ${i}(${xy})`);
+    }
+  }
+
+  this.coordinates.toString = function () {
+    return this.map(n => {
+      return (Math.round(n * 100) / 100 + "").replace(/^0\./, ".");
+    }) + "";
+  };
+}
+
+exports.CubicBezier = CubicBezier;
+
+CubicBezier.prototype = {
+  get P1() {
+    return this.coordinates.slice(0, 2);
+  },
+
+  get P2() {
+    return this.coordinates.slice(2);
+  },
+
+  toString: function () {
+    // Check first if current coords are one of css predefined functions
+    let predefName = Object.keys(PREDEFINED)
+                           .find(key => coordsAreEqual(PREDEFINED[key],
+                                                       this.coordinates));
+
+    return predefName || "cubic-bezier(" + this.coordinates + ")";
+  }
+};
+
+/**
+ * Bezier curve canvas plotting class
+ * @param {DOMNode} canvas
+ * @param {CubicBezier} bezier
+ * @param {Array} padding Amount of horizontal,vertical padding around the graph
+ */
+function BezierCanvas(canvas, bezier, padding) {
+  this.canvas = canvas;
+  this.bezier = bezier;
+  this.padding = getPadding(padding);
+
+  // Convert to a cartesian coordinate system with axes from 0 to 1
+  this.ctx = this.canvas.getContext("2d");
+  let p = this.padding;
+
+  this.ctx.scale(canvas.width * (1 - p[1] - p[3]),
+                 -canvas.height * (1 - p[0] - p[2]));
+  this.ctx.translate(p[3] / (1 - p[1] - p[3]),
+                     -1 - p[0] / (1 - p[0] - p[2]));
+}
+
+exports.BezierCanvas = BezierCanvas;
+
+BezierCanvas.prototype = {
+  /**
+   * Get P1 and P2 current top/left offsets so they can be positioned
+   * @return {Array} Returns an array of 2 {top:String,left:String} objects
+   */
+  get offsets() {
+    let p = this.padding, w = this.canvas.width, h = this.canvas.height;
+
+    return [{
+      left: w * (this.bezier.coordinates[0] * (1 - p[3] - p[1]) - p[3]) + "px",
+      top: h * (1 - this.bezier.coordinates[1] * (1 - p[0] - p[2]) - p[0])
+           + "px"
+    }, {
+      left: w * (this.bezier.coordinates[2] * (1 - p[3] - p[1]) - p[3]) + "px",
+      top: h * (1 - this.bezier.coordinates[3] * (1 - p[0] - p[2]) - p[0])
+           + "px"
+    }];
+  },
+
+  /**
+   * Convert an element's left/top offsets into coordinates
+   */
+  offsetsToCoordinates: function (element) {
+    let p = this.padding, w = this.canvas.width, h = this.canvas.height;
+
+    // Convert padding percentage to actual padding
+    p = p.map((a, i) => a * (i % 2 ? w : h));
+
+    return [
+      (parseFloat(element.style.left) - p[3]) / (w + p[1] + p[3]),
+      (h - parseFloat(element.style.top) - p[2]) / (h - p[0] - p[2])
+    ];
+  },
+
+  /**
+   * Draw the cubic bezier curve for the current coordinates
+   */
+  plot: function (settings = {}) {
+    let xy = this.bezier.coordinates;
+
+    let defaultSettings = {
+      handleColor: "#666",
+      handleThickness: .008,
+      bezierColor: "#4C9ED9",
+      bezierThickness: .015,
+      drawHandles: true
+    };
+
+    for (let setting in settings) {
+      defaultSettings[setting] = settings[setting];
+    }
+
+    // Clear the canvas –making sure to clear the
+    // whole area by resetting the transform first.
+    this.ctx.save();
+    this.ctx.setTransform(1, 0, 0, 1, 0, 0);
+    this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
+    this.ctx.restore();
+
+    if (defaultSettings.drawHandles) {
+      // Draw control handles
+      this.ctx.beginPath();
+      this.ctx.fillStyle = defaultSettings.handleColor;
+      this.ctx.lineWidth = defaultSettings.handleThickness;
+      this.ctx.strokeStyle = defaultSettings.handleColor;
+
+      this.ctx.moveTo(0, 0);
+      this.ctx.lineTo(xy[0], xy[1]);
+      this.ctx.moveTo(1, 1);
+      this.ctx.lineTo(xy[2], xy[3]);
+
+      this.ctx.stroke();
+      this.ctx.closePath();
+
+      let circle = (ctx, cx, cy, r) => {
+        ctx.beginPath();
+        ctx.arc(cx, cy, r, 0, 2 * Math.PI, !1);
+        ctx.closePath();
+      };
+
+      circle(this.ctx, xy[0], xy[1], 1.5 * defaultSettings.handleThickness);
+      this.ctx.fill();
+      circle(this.ctx, xy[2], xy[3], 1.5 * defaultSettings.handleThickness);
+      this.ctx.fill();
+    }
+
+    // Draw bezier curve
+    this.ctx.beginPath();
+    this.ctx.lineWidth = defaultSettings.bezierThickness;
+    this.ctx.strokeStyle = defaultSettings.bezierColor;
+    this.ctx.moveTo(0, 0);
+    this.ctx.bezierCurveTo(xy[0], xy[1], xy[2], xy[3], 1, 1);
+    this.ctx.stroke();
+    this.ctx.closePath();
+  }
+};
+
+/**
+ * Cubic-bezier widget. Uses the BezierCanvas class to draw the curve and
+ * adds the control points and user interaction
+ * @param {DOMNode} parent The container where the graph should be created
+ * @param {Array} coordinates Coordinates of the curve to be drawn
+ *
+ * Emits "updated" events whenever the curve is changed. Along with the event is
+ * sent a CubicBezier object
+ */
+function CubicBezierWidget(parent,
+                           coordinates = PRESETS["ease-in"]["ease-in-sine"]) {
+  EventEmitter.decorate(this);
+
+  this.parent = parent;
+  let {curve, p1, p2} = this._initMarkup();
+
+  this.curveBoundingBox = curve.getBoundingClientRect();
+  this.curve = curve;
+  this.p1 = p1;
+  this.p2 = p2;
+
+  // Create and plot the bezier curve
+  this.bezierCanvas = new BezierCanvas(this.curve,
+    new CubicBezier(coordinates), [0.30, 0]);
+  this.bezierCanvas.plot();
+
+  // Place the control points
+  let offsets = this.bezierCanvas.offsets;
+  this.p1.style.left = offsets[0].left;
+  this.p1.style.top = offsets[0].top;
+  this.p2.style.left = offsets[1].left;
+  this.p2.style.top = offsets[1].top;
+
+  this._onPointMouseDown = this._onPointMouseDown.bind(this);
+  this._onPointKeyDown = this._onPointKeyDown.bind(this);
+  this._onCurveClick = this._onCurveClick.bind(this);
+  this._onNewCoordinates = this._onNewCoordinates.bind(this);
+
+  // Add preset preview menu
+  this.presets = new CubicBezierPresetWidget(parent);
+
+  // Add the timing function previewer
+  this.timingPreview = new TimingFunctionPreviewWidget(parent);
+
+  this._initEvents();
+}
+
+exports.CubicBezierWidget = CubicBezierWidget;
+
+CubicBezierWidget.prototype = {
+  _initMarkup: function () {
+    let doc = this.parent.ownerDocument;
+
+    let wrap = doc.createElementNS(XHTML_NS, "div");
+    wrap.className = "display-wrap";
+
+    let plane = doc.createElementNS(XHTML_NS, "div");
+    plane.className = "coordinate-plane";
+
+    let p1 = doc.createElementNS(XHTML_NS, "button");
+    p1.className = "control-point";
+    plane.appendChild(p1);
+
+    let p2 = doc.createElementNS(XHTML_NS, "button");
+    p2.className = "control-point";
+    plane.appendChild(p2);
+
+    let curve = doc.createElementNS(XHTML_NS, "canvas");
+    curve.setAttribute("width", 150);
+    curve.setAttribute("height", 370);
+    curve.className = "curve";
+
+    plane.appendChild(curve);
+    wrap.appendChild(plane);
+
+    this.parent.appendChild(wrap);
+
+    return {
+      p1,
+      p2,
+      curve
+    };
+  },
+
+  _removeMarkup: function () {
+    this.parent.querySelector(".display-wrap").remove();
+  },
+
+  _initEvents: function () {
+    this.p1.addEventListener("mousedown", this._onPointMouseDown);
+    this.p2.addEventListener("mousedown", this._onPointMouseDown);
+
+    this.p1.addEventListener("keydown", this._onPointKeyDown);
+    this.p2.addEventListener("keydown", this._onPointKeyDown);
+
+    this.curve.addEventListener("click", this._onCurveClick);
+
+    this.presets.on("new-coordinates", this._onNewCoordinates);
+  },
+
+  _removeEvents: function () {
+    this.p1.removeEventListener("mousedown", this._onPointMouseDown);
+    this.p2.removeEventListener("mousedown", this._onPointMouseDown);
+
+    this.p1.removeEventListener("keydown", this._onPointKeyDown);
+    this.p2.removeEventListener("keydown", this._onPointKeyDown);
+
+    this.curve.removeEventListener("click", this._onCurveClick);
+
+    this.presets.off("new-coordinates", this._onNewCoordinates);
+  },
+
+  _onPointMouseDown: function (event) {
+    // Updating the boundingbox in case it has changed
+    this.curveBoundingBox = this.curve.getBoundingClientRect();
+
+    let point = event.target;
+    let doc = point.ownerDocument;
+    let self = this;
+
+    doc.onmousemove = function drag(e) {
+      let x = e.pageX;
+      let y = e.pageY;
+      let left = self.curveBoundingBox.left;
+      let top = self.curveBoundingBox.top;
+
+      if (x === 0 && y == 0) {
+        return;
+      }
+
+      // Constrain x
+      x = Math.min(Math.max(left, x), left + self.curveBoundingBox.width);
+
+      point.style.left = x - left + "px";
+      point.style.top = y - top + "px";
+
+      self._updateFromPoints();
+    };
+
+    doc.onmouseup = function () {
+      point.focus();
+      doc.onmousemove = doc.onmouseup = null;
+    };
+  },
+
+  _onPointKeyDown: function (event) {
+    let point = event.target;
+    let code = event.keyCode;
+
+    if (code >= 37 && code <= 40) {
+      event.preventDefault();
+
+      // Arrow keys pressed
+      let left = parseInt(point.style.left, 10);
+      let top = parseInt(point.style.top, 10);
+      let offset = 3 * (event.shiftKey ? 10 : 1);
+
+      switch (code) {
+        case 37: point.style.left = left - offset + "px"; break;
+        case 38: point.style.top = top - offset + "px"; break;
+        case 39: point.style.left = left + offset + "px"; break;
+        case 40: point.style.top = top + offset + "px"; break;
+      }
+
+      this._updateFromPoints();
+    }
+  },
+
+  _onCurveClick: function (event) {
+    this.curveBoundingBox = this.curve.getBoundingClientRect();
+
+    let left = this.curveBoundingBox.left;
+    let top = this.curveBoundingBox.top;
+    let x = event.pageX - left;
+    let y = event.pageY - top;
+
+    // Find which point is closer
+    let distP1 = distance(x, y,
+      parseInt(this.p1.style.left, 10), parseInt(this.p1.style.top, 10));
+    let distP2 = distance(x, y,
+      parseInt(this.p2.style.left, 10), parseInt(this.p2.style.top, 10));
+
+    let point = distP1 < distP2 ? this.p1 : this.p2;
+    point.style.left = x + "px";
+    point.style.top = y + "px";
+
+    this._updateFromPoints();
+  },
+
+  _onNewCoordinates: function (event, coordinates) {
+    this.coordinates = coordinates;
+  },
+
+  /**
+   * Get the current point coordinates and redraw the curve to match
+   */
+  _updateFromPoints: function () {
+    // Get the new coordinates from the point's offsets
+    let coordinates = this.bezierCanvas.offsetsToCoordinates(this.p1);
+    coordinates = coordinates.concat(
+      this.bezierCanvas.offsetsToCoordinates(this.p2)
+    );
+
+    this.presets.refreshMenu(coordinates);
+    this._redraw(coordinates);
+  },
+
+  /**
+   * Redraw the curve
+   * @param {Array} coordinates The array of control point coordinates
+   */
+  _redraw: function (coordinates) {
+    // Provide a new CubicBezier to the canvas and plot the curve
+    this.bezierCanvas.bezier = new CubicBezier(coordinates);
+    this.bezierCanvas.plot();
+    this.emit("updated", this.bezierCanvas.bezier);
+
+    this.timingPreview.preview(this.bezierCanvas.bezier + "");
+  },
+
+  /**
+   * Set new coordinates for the control points and redraw the curve
+   * @param {Array} coordinates
+   */
+  set coordinates(coordinates) {
+    this._redraw(coordinates);
+
+    // Move the points
+    let offsets = this.bezierCanvas.offsets;
+    this.p1.style.left = offsets[0].left;
+    this.p1.style.top = offsets[0].top;
+    this.p2.style.left = offsets[1].left;
+    this.p2.style.top = offsets[1].top;
+  },
+
+  /**
+   * Set new coordinates for the control point and redraw the curve
+   * @param {String} value A string value. E.g. "linear",
+   * "cubic-bezier(0,0,1,1)"
+   */
+  set cssCubicBezierValue(value) {
+    if (!value) {
+      return;
+    }
+
+    value = value.trim();
+
+    // Try with one of the predefined values
+    let coordinates = parseTimingFunction(value);
+
+    this.presets.refreshMenu(coordinates);
+    this.coordinates = coordinates;
+  },
+
+  destroy: function () {
+    this._removeEvents();
+    this._removeMarkup();
+
+    this.timingPreview.destroy();
+    this.presets.destroy();
+
+    this.curve = this.p1 = this.p2 = null;
+  }
+};
+
+/**
+ * CubicBezierPreset widget.
+ * Builds a menu of presets from CubicBezierPresets
+ * @param {DOMNode} parent The container where the preset panel should be
+ * created
+ *
+ * Emits "new-coordinate" event along with the coordinates
+ * whenever a preset is selected.
+ */
+function CubicBezierPresetWidget(parent) {
+  this.parent = parent;
+
+  let {presetPane, presets, categories} = this._initMarkup();
+  this.presetPane = presetPane;
+  this.presets = presets;
+  this.categories = categories;
+
+  this._activeCategory = null;
+  this._activePresetList = null;
+  this._activePreset = null;
+
+  this._onCategoryClick = this._onCategoryClick.bind(this);
+  this._onPresetClick = this._onPresetClick.bind(this);
+
+  EventEmitter.decorate(this);
+  this._initEvents();
+}
+
+exports.CubicBezierPresetWidget = CubicBezierPresetWidget;
+
+CubicBezierPresetWidget.prototype = {
+  /*
+   * Constructs a list of all preset categories and a list
+   * of presets for each category.
+   *
+   * High level markup:
+   *  div .preset-pane
+   *    div .preset-categories
+   *      div .category
+   *      div .category
+   *      ...
+   *    div .preset-container
+   *      div .presetList
+   *        div .preset
+   *        ...
+   *      div .presetList
+   *        div .preset
+   *        ...
+   */
+  _initMarkup: function () {
+    let doc = this.parent.ownerDocument;
+
+    let presetPane = doc.createElementNS(XHTML_NS, "div");
+    presetPane.className = "preset-pane";
+
+    let categoryList = doc.createElementNS(XHTML_NS, "div");
+    categoryList.id = "preset-categories";
+
+    let presetContainer = doc.createElementNS(XHTML_NS, "div");
+    presetContainer.id = "preset-container";
+
+    Object.keys(PRESETS).forEach(categoryLabel => {
+      let category = this._createCategory(categoryLabel);
+      categoryList.appendChild(category);
+
+      let presetList = this._createPresetList(categoryLabel);
+      presetContainer.appendChild(presetList);
+    });
+
+    presetPane.appendChild(categoryList);
+    presetPane.appendChild(presetContainer);
+
+    this.parent.appendChild(presetPane);
+
+    let allCategories = presetPane.querySelectorAll(".category");
+    let allPresets = presetPane.querySelectorAll(".preset");
+
+    return {
+      presetPane: presetPane,
+      presets: allPresets,
+      categories: allCategories
+    };
+  },
+
+  _createCategory: function (categoryLabel) {
+    let doc = this.parent.ownerDocument;
+
+    let category = doc.createElementNS(XHTML_NS, "div");
+    category.id = categoryLabel;
+    category.classList.add("category");
+
+    let categoryDisplayLabel = this._normalizeCategoryLabel(categoryLabel);
+    category.textContent = categoryDisplayLabel;
+    category.setAttribute("title", categoryDisplayLabel);
+
+    return category;
+  },
+
+  _normalizeCategoryLabel: function (categoryLabel) {
+    return categoryLabel.replace("/-/g", " ");
+  },
+
+  _createPresetList: function (categoryLabel) {
+    let doc = this.parent.ownerDocument;
+
+    let presetList = doc.createElementNS(XHTML_NS, "div");
+    presetList.id = "preset-category-" + categoryLabel;
+    presetList.classList.add("preset-list");
+
+    Object.keys(PRESETS[categoryLabel]).forEach(presetLabel => {
+      let preset = this._createPreset(categoryLabel, presetLabel);
+      presetList.appendChild(preset);
+    });
+
+    return presetList;
+  },
+
+  _createPreset: function (categoryLabel, presetLabel) {
+    let doc = this.parent.ownerDocument;
+
+    let preset = doc.createElementNS(XHTML_NS, "div");
+    preset.classList.add("preset");
+    preset.id = presetLabel;
+    preset.coordinates = PRESETS[categoryLabel][presetLabel];
+    // Create preset preview
+    let curve = doc.createElementNS(XHTML_NS, "canvas");
+    let bezier = new CubicBezier(preset.coordinates);
+    curve.setAttribute("height", 50);
+    curve.setAttribute("width", 50);
+    preset.bezierCanvas = new BezierCanvas(curve, bezier, [0.15, 0]);
+    preset.bezierCanvas.plot({
+      drawHandles: false,
+      bezierThickness: 0.025
+    });
+    preset.appendChild(curve);
+
+    // Create preset label
+    let presetLabelElem = doc.createElementNS(XHTML_NS, "p");
+    let presetDisplayLabel = this._normalizePresetLabel(categoryLabel,
+                                                        presetLabel);
+    presetLabelElem.textContent = presetDisplayLabel;
+    preset.appendChild(presetLabelElem);
+    preset.setAttribute("title", presetDisplayLabel);
+
+    return preset;
+  },
+
+  _normalizePresetLabel: function (categoryLabel, presetLabel) {
+    return presetLabel.replace(categoryLabel + "-", "").replace("/-/g", " ");
+  },
+
+  _initEvents: function () {
+    for (let category of this.categories) {
+      category.addEventListener("click", this._onCategoryClick);
+    }
+
+    for (let preset of this.presets) {
+      preset.addEventListener("click", this._onPresetClick);
+    }
+  },
+
+  _removeEvents: function () {
+    for (let category of this.categories) {
+      category.removeEventListener("click", this._onCategoryClick);
+    }
+
+    for (let preset of this.presets) {
+      preset.removeEventListener("click", this._onPresetClick);
+    }
+  },
+
+  _onPresetClick: function (event) {
+    this.emit("new-coordinates", event.currentTarget.coordinates);
+    this.activePreset = event.currentTarget;
+  },
+
+  _onCategoryClick: function (event) {
+    this.activeCategory = event.target;
+  },
+
+  _setActivePresetList: function (presetListId) {
+    let presetList = this.presetPane.querySelector("#" + presetListId);
+    swapClassName("active-preset-list", this._activePresetList, presetList);
+    this._activePresetList = presetList;
+  },
+
+  set activeCategory(category) {
+    swapClassName("active-category", this._activeCategory, category);
+    this._activeCategory = category;
+    this._setActivePresetList("preset-category-" + category.id);
+  },
+
+  get activeCategory() {
+    return this._activeCategory;
+  },
+
+  set activePreset(preset) {
+    swapClassName("active-preset", this._activePreset, preset);
+    this._activePreset = preset;
+  },
+
+  get activePreset() {
+    return this._activePreset;
+  },
+
+  /**
+   * Called by CubicBezierWidget onload and when
+   * the curve is modified via the canvas.
+   * Attempts to match the new user setting with an
+   * existing preset.
+   * @param {Array} coordinates new coords [i, j, k, l]
+   */
+  refreshMenu: function (coordinates) {
+    // If we cannot find a matching preset, keep
+    // menu on last known preset category.
+    let category = this._activeCategory;
+
+    // If we cannot find a matching preset
+    // deselect any selected preset.
+    let preset = null;
+
+    // If a category has never been viewed before
+    // show the default category.
+    if (!category) {
+      category = this.parent.querySelector("#" + DEFAULT_PRESET_CATEGORY);
+    }
+
+    // If the new coordinates do match a preset,
+    // set its category and preset button as active.
+    Object.keys(PRESETS).forEach(categoryLabel => {
+      Object.keys(PRESETS[categoryLabel]).forEach(presetLabel => {
+        if (coordsAreEqual(PRESETS[categoryLabel][presetLabel], coordinates)) {
+          category = this.parent.querySelector("#" + categoryLabel);
+          preset = this.parent.querySelector("#" + presetLabel);
+        }
+      });
+    });
+
+    this.activeCategory = category;
+    this.activePreset = preset;
+  },
+
+  destroy: function () {
+    this._removeEvents();
+    this.parent.querySelector(".preset-pane").remove();
+  }
+};
+
+/**
+ * The TimingFunctionPreviewWidget animates a dot on a scale with a given
+ * timing-function
+ * @param {DOMNode} parent The container where this widget should go
+ */
+function TimingFunctionPreviewWidget(parent) {
+  this.previousValue = null;
+  this.autoRestartAnimation = null;
+
+  this.parent = parent;
+  this._initMarkup();
+}
+
+TimingFunctionPreviewWidget.prototype = {
+  PREVIEW_DURATION: 1000,
+
+  _initMarkup: function () {
+    let doc = this.parent.ownerDocument;
+
+    let container = doc.createElementNS(XHTML_NS, "div");
+    container.className = "timing-function-preview";
+
+    this.dot = doc.createElementNS(XHTML_NS, "div");
+    this.dot.className = "dot";
+    container.appendChild(this.dot);
+
+    let scale = doc.createElementNS(XHTML_NS, "div");
+    scale.className = "scale";
+    container.appendChild(scale);
+
+    this.parent.appendChild(container);
+  },
+
+  destroy: function () {
+    clearTimeout(this.autoRestartAnimation);
+    this.parent.querySelector(".timing-function-preview").remove();
+    this.parent = this.dot = null;
+  },
+
+  /**
+   * Preview a new timing function. The current preview will only be stopped if
+   * the supplied function value is different from the previous one. If the
+   * supplied function is invalid, the preview will stop.
+   * @param {String} value
+   */
+  preview: function (value) {
+    // Don't restart the preview animation if the value is the same
+    if (value === this.previousValue) {
+      return;
+    }
+
+    clearTimeout(this.autoRestartAnimation);
+
+    if (parseTimingFunction(value)) {
+      this.dot.style.animationTimingFunction = value;
+      this.restartAnimation();
+    }
+
+    this.previousValue = value;
+  },
+
+  /**
+   * Re-start the preview animation from the beginning
+   */
+  restartAnimation: function () {
+    // Just toggling the class won't do it unless there's a sync reflow
+    this.dot.animate([
+      { left: "-7px", offset: 0 },
+      { left: "143px", offset: 0.25 },
+      { left: "143px", offset: 0.5 },
+      { left: "-7px", offset: 0.75 },
+      { left: "-7px", offset: 1 }
+    ], {
+      duration: (this.PREVIEW_DURATION * 2),
+      fill: "forwards"
+    });
+
+    // Restart it again after a while
+    this.autoRestartAnimation = setTimeout(this.restartAnimation.bind(this),
+      this.PREVIEW_DURATION * 2);
+  }
+};
+
+// Helpers
+
+function getPadding(padding) {
+  let p = typeof padding === "number" ? [padding] : padding;
+
+  if (p.length === 1) {
+    p[1] = p[0];
+  }
+
+  if (p.length === 2) {
+    p[2] = p[0];
+  }
+
+  if (p.length === 3) {
+    p[3] = p[1];
+  }
+
+  return p;
+}
+
+function distance(x1, y1, x2, y2) {
+  return Math.sqrt(Math.pow(x1 - x2, 2) + Math.pow(y1 - y2, 2));
+}
+
+/**
+ * Parse a string to see whether it is a valid timing function.
+ * If it is, return the coordinates as an array.
+ * Otherwise, return undefined.
+ * @param {String} value
+ * @return {Array} of coordinates, or undefined
+ */
+function parseTimingFunction(value) {
+  if (value in PREDEFINED) {
+    return PREDEFINED[value];
+  }
+
+  let tokenStream = getCSSLexer(value);
+  let getNextToken = () => {
+    while (true) {
+      let token = tokenStream.nextToken();
+      if (!token || (token.tokenType !== "whitespace" &&
+                     token.tokenType !== "comment")) {
+        return token;
+      }
+    }
+  };
+
+  let token = getNextToken();
+  if (token.tokenType !== "function" || token.text !== "cubic-bezier") {
+    return undefined;
+  }
+
+  let result = [];
+  for (let i = 0; i < 4; ++i) {
+    token = getNextToken();
+    if (!token || token.tokenType !== "number") {
+      return undefined;
+    }
+    result.push(token.number);
+
+    token = getNextToken();
+    if (!token || token.tokenType !== "symbol" ||
+        token.text !== (i == 3 ? ")" : ",")) {
+      return undefined;
+    }
+  }
+
+  return result;
+}
+
+// This is exported for testing.
+exports._parseTimingFunction = parseTimingFunction;
+
+/**
+ * Removes a class from a node and adds it to another.
+ * @param {String} className the class to swap
+ * @param {DOMNode} from the node to remove the class from
+ * @param {DOMNode} to the node to add the class to
+ */
+function swapClassName(className, from, to) {
+  if (from !== null) {
+    from.classList.remove(className);
+  }
+
+  if (to !== null) {
+    to.classList.add(className);
+  }
+}
+
+/**
+ * Compares two arrays of coordinates [i, j, k, l]
+ * @param {Array} c1 first coordinate array to compare
+ * @param {Array} c2 second coordinate array to compare
+ * @return {Boolean}
+ */
+function coordsAreEqual(c1, c2) {
+  return c1.reduce((prev, curr, index) => prev && (curr === c2[index]), true);
+}