Add third_party/google-input-tools: Take 2

third_party/google_input_tools/src/chrome/os/inputview/strokehandler.js

+// Copyright 2014 The ChromeOS IME Authors. All Rights Reserved.
+// limitations under the License.
+// See the License for the specific language governing permissions and
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// distributed under the License is distributed on an "AS-IS" BASIS,
+// Unless required by applicable law or agreed to in writing, software
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// You may obtain a copy of the License at
+// you may not use this file except in compliance with the License.
+// Licensed under the Apache License, Version 2.0 (the "License");
+//
+
+/**
+ * @fileoverview Defines the class i18n.input.hwt.StrokeHandler.
+ * @author fengyuan@google.com (Feng Yuan)
+ */
+
+goog.provide('i18n.input.hwt.StrokeHandler');
+goog.provide('i18n.input.hwt.StrokeHandler.Point');
+goog.provide('i18n.input.hwt.StrokeHandler.StrokeEvent');
+
+
+goog.require('goog.events');
+goog.require('goog.events.Event');
+goog.require('goog.events.EventHandler');
+goog.require('goog.events.EventTarget');
+goog.require('goog.events.EventType');
+goog.require('goog.style');
+goog.require('goog.userAgent');
+goog.require('i18n.input.hwt.util');
+
+
+
+/**
+ * The handler for strokes.
+ *
+ * @param {!Element} canvas The handwriting canvas.
+ * @param {!Document} topDocument The top document.
+ * @constructor
+ * @extends {goog.events.EventTarget}
+ */
+i18n.input.hwt.StrokeHandler = function(canvas, topDocument) {
+  goog.base(this);
+
+  /**
+   * The event handler.
+   *
+   * @type {goog.events.EventHandler}
+   * @private
+   */
+  this.eventHandler_ = new goog.events.EventHandler(this);
+
+  /**
+   * Whether is drawing the stroke.
+   *
+   * @type {boolean}
+   */
+  this.drawing = false;
+
+  /**
+   * The canvas.
+   *
+   * @type {Element}
+   * @private
+   */
+  this.canvas_ = canvas;
+
+  // Always register mouse events. Some devices like Tablet PCs
+  // actually support both touch and mouse events, and the touch
+  // events don't get translated to mouse events on Tablet PCs.
+  this.eventHandler_.
+      listen(canvas, goog.events.EventType.MOUSEDOWN, this.onStrokeStart_).
+      listen(canvas, goog.events.EventType.MOUSEMOVE, this.onStroke_);
+  // Listen for touch events if they are supported.
+  if ('ontouchstart' in window) {
+    this.eventHandler_.
+        listen(canvas, goog.events.EventType.TOUCHSTART, this.onStrokeStart_).
+        listen(canvas, goog.events.EventType.TOUCHEND, this.onStrokeEnd_).
+        listen(canvas, goog.events.EventType.TOUCHCANCEL, this.onStrokeEnd_).
+        listen(canvas, goog.events.EventType.TOUCHMOVE, this.onStroke_);
+  }
+
+  i18n.input.hwt.util.listenPageEvent(this.eventHandler_, topDocument,
+      goog.events.EventType.MOUSEUP,
+      goog.bind(this.onStrokeEnd_, this));
+};
+goog.inherits(i18n.input.hwt.StrokeHandler, goog.events.EventTarget);
+
+
+/**
+ * Callback for the start of one stroke.
+ *
+ * @param {goog.events.BrowserEvent} e Event.
+ * @private
+ */
+i18n.input.hwt.StrokeHandler.prototype.onStrokeStart_ = function(e) {
+  this.drawing = true;
+  this.dispatchEvent(new i18n.input.hwt.StrokeHandler.StrokeEvent(
+      i18n.input.hwt.StrokeHandler.EventType.STROKE_START,
+      this.getPoint_(e)));
+  e.preventDefault();
+};
+
+
+/**
+ * Callback for the end of one stroke.
+ *
+ * @param {goog.events.BrowserEvent} e Event.
+ * @private
+ */
+i18n.input.hwt.StrokeHandler.prototype.onStrokeEnd_ = function(e) {
+  if (this.drawing) {
+    this.drawing = false;
+    this.dispatchEvent(new i18n.input.hwt.StrokeHandler.StrokeEvent(
+        i18n.input.hwt.StrokeHandler.EventType.STROKE_END,
+        this.getPoint_(e)));
+    e.preventDefault();
+  }
+};
+
+
+/**
+ * Callback for stroke.
+ *
+ * @param {goog.events.BrowserEvent} e Event.
+ * @private
+ */
+i18n.input.hwt.StrokeHandler.prototype.onStroke_ = function(e) {
+  if (this.drawing) {
+    this.dispatchEvent(new i18n.input.hwt.StrokeHandler.StrokeEvent(
+        i18n.input.hwt.StrokeHandler.EventType.STROKE,
+        this.getPoint_(e)));
+  }
+  e.preventDefault();
+};
+
+
+/**
+ * Given a mouse or touch event, figure out the coordinates where it occurred.
+ *
+ * @param {goog.events.BrowserEvent} e Event.
+ * @return {!i18n.input.hwt.StrokeHandler.Point} a point.
+ * @private
+ */
+i18n.input.hwt.StrokeHandler.prototype.getPoint_ = function(e) {
+  var pos = goog.style.getPageOffset(this.canvas_);
+  var nativeEvent = e.getBrowserEvent();
+  var x, y;
+  if (!goog.userAgent.IE && nativeEvent.pageX && nativeEvent.pageY) {
+    x = nativeEvent.pageX;
+    y = nativeEvent.pageY;
+  } else {
+    var scrollX = (document.dir == 'rtl' ? -1 : 1) * (
+        document.body.scrollLeft ||
+        document.documentElement.scrollLeft || 0);
+    var scrollY = document.body.scrollTop ||
+        document.documentElement.scrollTop || 0;
+    x = nativeEvent.clientX + scrollX;
+    y = nativeEvent.clientY + scrollY;
+  }
+  if (nativeEvent.touches != null && nativeEvent.touches.length > 0) {
+    x = nativeEvent.touches[0].clientX;
+    y = nativeEvent.touches[0].clientY;
+  }
+  return new i18n.input.hwt.StrokeHandler.Point(x - pos.x, y - pos.y,
+      goog.now());
+};
+
+
+/**
+ * Reset the drawing flag, in case the drawing canvas gets cleared while
+ * stroke is being drawn.
+ */
+i18n.input.hwt.StrokeHandler.prototype.reset = function() {
+  this.drawing = false;
+};
+
+
+/** @override */
+i18n.input.hwt.StrokeHandler.prototype.disposeInternal = function() {
+  goog.dispose(this.eventHandler_);
+  this.eventHandler_ = null;
+};
+
+
+
+/**
+ * One point in the stroke.
+ *
+ * @param {number} x The x.
+ * @param {number} y The y.
+ * @param {number} time The time in milisecond.
+ * @constructor
+ */
+i18n.input.hwt.StrokeHandler.Point = function(x, y, time) {
+  /**
+   * The left offset relative to the canvas.
+   *
+   * @type {number}
+   */
+  this.x = x;
+
+  /**
+   * The top offset relative to the canvas.
+   *
+   * @type {number}
+   */
+  this.y = y;
+
+  /**
+   * The time.
+   *
+   * @type {number}
+   */
+  this.time = time;
+};
+
+
+/**
+ * Stroke events.
+ *
+ * @enum {string}
+ */
+i18n.input.hwt.StrokeHandler.EventType = {
+  STROKE: goog.events.getUniqueId('s'),
+  STROKE_END: goog.events.getUniqueId('se'),
+  STROKE_START: goog.events.getUniqueId('ss')
+};
+
+
+
+/**
+ * The stroke event.
+ *
+ * @param {!i18n.input.hwt.StrokeHandler.EventType} type The event type.
+ * @param {!i18n.input.hwt.StrokeHandler.Point} point The point.
+ * @constructor
+ * @extends {goog.events.Event}
+ */
+i18n.input.hwt.StrokeHandler.StrokeEvent = function(type, point) {
+  goog.base(this, type);
+
+  /**
+   * The point.
+   *
+   * @type {!i18n.input.hwt.StrokeHandler.Point}
+   */
+  this.point = point;
+};
+goog.inherits(i18n.input.hwt.StrokeHandler.StrokeEvent, goog.events.Event);