1 files changed, 77 insertions, 0 deletions
diff --git a/catapult/telemetry/telemetry/internal/actions/pinch.js b/catapult/telemetry/telemetry/internal/actions/pinch.js
new file mode 100644
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+++ b/catapult/telemetry/telemetry/internal/actions/pinch.js
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+// Copyright 2013 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.
+
+// This file provides the PinchAction object, which zooms into or out of a
+// page by a given scale factor:
+//   1. var action = new __PinchAction(callback)
+//   2. action.start(pinch_options)
+'use strict';
+
+(function() {
+
+  function PinchGestureOptions(opt_options) {
+    if (opt_options) {
+      this.element_ = opt_options.element;
+      this.left_anchor_ratio_ = opt_options.left_anchor_ratio;
+      this.top_anchor_ratio_ = opt_options.top_anchor_ratio;
+      this.scale_factor_ = opt_options.scale_factor;
+      this.speed_ = opt_options.speed;
+    } else {
+      this.element_ = document.body;
+      this.left_anchor_ratio_ = 0.5;
+      this.top_anchor_ratio_ = 0.5;
+      this.scale_factor_ = 2.0;
+      this.speed_ = 800;
+    }
+  }
+
+  function supportedByBrowser() {
+    return !!(window.chrome &&
+              chrome.gpuBenchmarking &&
+              chrome.gpuBenchmarking.pinchBy &&
+              chrome.gpuBenchmarking.visualViewportHeight &&
+              chrome.gpuBenchmarking.visualViewportWidth);
+  }
+
+  // This class zooms into or out of a page, given a number of pixels for
+  // the synthetic pinch gesture to cover.
+  function PinchAction(opt_callback) {
+    var self = this;
+
+    this.beginMeasuringHook = function() {};
+    this.endMeasuringHook = function() {};
+
+    this.callback_ = opt_callback;
+  };
+
+  PinchAction.prototype.start = function(opt_options) {
+    this.options_ = new PinchGestureOptions(opt_options);
+
+    requestAnimationFrame(this.startPass_.bind(this));
+  };
+
+  PinchAction.prototype.startPass_ = function() {
+    this.beginMeasuringHook();
+
+    var rect = __GestureCommon_GetBoundingVisibleRect(this.options_.element_);
+    var anchor_left =
+        rect.left + rect.width * this.options_.left_anchor_ratio_;
+    var anchor_top =
+        rect.top + rect.height * this.options_.top_anchor_ratio_;
+    chrome.gpuBenchmarking.pinchBy(this.options_.scale_factor_,
+                                   anchor_left, anchor_top,
+                                   this.onGestureComplete_.bind(this),
+                                   this.options_.speed_);
+  };
+
+  PinchAction.prototype.onGestureComplete_ = function() {
+    this.endMeasuringHook();
+
+    if (this.callback_)
+      this.callback_();
+  };
+
+  window.__PinchAction = PinchAction;
+  window.__PinchAction_SupportedByBrowser = supportedByBrowser;
+})();