GUACAMOLE-1204: Extract Guacamole.Position base class from Guacamole.Mouse.State.

guacamole-common-js/src/main/webapp/modules/Position.js

@@ -0,0 +1,92 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+var Guacamole = Guacamole || {};
+
+/**
+ * A position in 2-D space.
+ *
+ * @constructor
+ * @param {Guacamole.Position|Object} [template={}]
+ *     The object whose properties should be copied within the new
+ *     Guacamole.Position.
+ */
+Guacamole.Position = function Position(template) {
+
+    template = template || {};
+
+    /**
+     * The current X position, in pixels.
+     *
+     * @type {Number}
+     * @default 0
+     */
+    this.x = template.x || 0;
+
+    /**
+     * The current Y position, in pixels.
+     *
+     * @type {Number}
+     * @default 0
+     */
+    this.y = template.y || 0;
+
+    /**
+     * Assigns the position represented by the given element and
+     * clientX/clientY coordinates. The clientX and clientY coordinates are
+     * relative to the browser viewport and are commonly available within
+     * JavaScript event objects. The final position is translated to
+     * coordinates that are relative the given element.
+     *
+     * @param {Element} element
+     *     The element the coordinates should be relative to.
+     *
+     * @param {Number} clientX
+     *     The viewport-relative X coordinate to translate.
+     *
+     * @param {Number} clientY
+     *     The viewport-relative Y coordinate to translate.
+     */
+    this.fromClientPosition = function fromClientPosition(element, clientX, clientY) {
+
+        this.x = clientX - element.offsetLeft;
+        this.y = clientY - element.offsetTop;
+
+        // This is all JUST so we can get the position within the element
+        var parent = element.offsetParent;
+        while (parent && !(parent === document.body)) {
+            this.x -= parent.offsetLeft - parent.scrollLeft;
+            this.y -= parent.offsetTop  - parent.scrollTop;
+
+            parent = parent.offsetParent;
+        }
+
+        // Element ultimately depends on positioning within document body,
+        // take document scroll into account.
+        if (parent) {
+            var documentScrollLeft = document.body.scrollLeft || document.documentElement.scrollLeft;
+            var documentScrollTop = document.body.scrollTop || document.documentElement.scrollTop;
+
+            this.x -= parent.offsetLeft - documentScrollLeft;
+            this.y -= parent.offsetTop  - documentScrollTop;
+        }
+
+    };
+
+};