gecko/toolkit/content/WindowDraggingUtils.jsm

/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org Code.
 *
 * The Initial Developer of the Original Code is
 * Markus Stange <mstange@themasta.com>.
 * Portions created by the Initial Developer are Copyright (C) 2008
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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let EXPORTED_SYMBOLS = [ "WindowDraggingElement" ];

function WindowDraggingElement(elem, window) {
  this._elem = elem;
  this._window = window;
  this._elem.addEventListener("mousedown", this, false);
}

WindowDraggingElement.prototype = {
  mouseDownCheck: function(e) { return true; },
  dragTags: ["box", "hbox", "vbox", "spacer", "label", "statusbarpanel", "stack",
             "toolbaritem", "toolbarseparator", "toolbarspring", "toolbarspacer",
             "radiogroup"],
  handleEvent: function(aEvent) {
    switch (aEvent.type) {
      case "mousedown":
        if (aEvent.button != 0 || !this.mouseDownCheck.call(this._elem, aEvent))
          return;

        let target = aEvent.originalTarget, parent = aEvent.originalTarget;
        while (parent != this._elem) {
          let mousethrough = parent.getAttribute("mousethrough");
          if (mousethrough == "always")
            target = parent.parentNode;
          else if (mousethrough == "never")
            break;
          parent = parent.parentNode;
        }
        while (target != this._elem) {
          if (this.dragTags.indexOf(target.localName) == -1)
            return;
          target = target.parentNode;
        }
        this._deltaX = aEvent.screenX - this._window.screenX;
        this._deltaY = aEvent.screenY - this._window.screenY;
        this._draggingWindow = true;
        this._window.addEventListener("mousemove", this, false);
        this._window.addEventListener("mouseup", this, false);
        break;
      case "mousemove":
        if (this._draggingWindow)
          this._window.moveTo(aEvent.screenX - this._deltaX, aEvent.screenY - this._deltaY);
        break;
      case "mouseup":
        this._draggingWindow = false;
        this._window.removeEventListener("mousemove", this, false);
        this._window.removeEventListener("mouseup", this, false);
        break;
    }
  }
}