1 files changed, 105 insertions, 0 deletions
diff --git a/devtools/client/animationinspector/components/rate-selector.js b/devtools/client/animationinspector/components/rate-selector.js
new file mode 100644
index 000000000..e46664e6a
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+++ b/devtools/client/animationinspector/components/rate-selector.js
@@ -0,0 +1,105 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const EventEmitter = require("devtools/shared/event-emitter");
+const {createNode} = require("devtools/client/animationinspector/utils");
+const { LocalizationHelper } = require("devtools/shared/l10n");
+const L10N =
+      new LocalizationHelper("devtools/client/locales/animationinspector.properties");
+
+// List of playback rate presets displayed in the timeline toolbar.
+const PLAYBACK_RATES = [.1, .25, .5, 1, 2, 5, 10];
+
+/**
+ * UI component responsible for displaying a playback rate selector UI.
+ * The rendering logic is such that a predefined list of rates is generated.
+ * If *all* animations passed to render share the same rate, then that rate is
+ * selected in the <select> element, otherwise, the empty value is selected.
+ * If the rate that all animations share isn't part of the list of predefined
+ * rates, than that rate is added to the list.
+ */
+function RateSelector() {
+  this.onRateChanged = this.onRateChanged.bind(this);
+  EventEmitter.decorate(this);
+}
+
+exports.RateSelector = RateSelector;
+
+RateSelector.prototype = {
+  init: function (containerEl) {
+    this.selectEl = createNode({
+      parent: containerEl,
+      nodeType: "select",
+      attributes: {
+        "class": "devtools-button",
+        "title": L10N.getStr("timeline.rateSelectorTooltip")
+      }
+    });
+
+    this.selectEl.addEventListener("change", this.onRateChanged);
+  },
+
+  destroy: function () {
+    this.selectEl.removeEventListener("change", this.onRateChanged);
+    this.selectEl.remove();
+    this.selectEl = null;
+  },
+
+  getAnimationsRates: function (animations) {
+    return sortedUnique(animations.map(a => a.state.playbackRate));
+  },
+
+  getAllRates: function (animations) {
+    let animationsRates = this.getAnimationsRates(animations);
+    if (animationsRates.length > 1) {
+      return PLAYBACK_RATES;
+    }
+
+    return sortedUnique(PLAYBACK_RATES.concat(animationsRates));
+  },
+
+  render: function (animations) {
+    let allRates = this.getAnimationsRates(animations);
+    let hasOneRate = allRates.length === 1;
+
+    this.selectEl.innerHTML = "";
+
+    if (!hasOneRate) {
+      // When the animations displayed have mixed playback rates, we can't
+      // select any of the predefined ones, instead, insert an empty rate.
+      createNode({
+        parent: this.selectEl,
+        nodeType: "option",
+        attributes: {value: "", selector: "true"},
+        textContent: "-"
+      });
+    }
+    for (let rate of this.getAllRates(animations)) {
+      let option = createNode({
+        parent: this.selectEl,
+        nodeType: "option",
+        attributes: {value: rate},
+        textContent: L10N.getFormatStr("player.playbackRateLabel", rate)
+      });
+
+      // If there's only one rate and this is the option for it, select it.
+      if (hasOneRate && rate === allRates[0]) {
+        option.setAttribute("selected", "true");
+      }
+    }
+  },
+
+  onRateChanged: function () {
+    let rate = parseFloat(this.selectEl.value);
+    if (!isNaN(rate)) {
+      this.emit("rate-changed", rate);
+    }
+  }
+};
+
+let sortedUnique = arr => [...new Set(arr)].sort((a, b) => a > b);