wbo1/client-data/tools/eraser/eraser.js

/**
 *                        WHITEBOPHIR
 *********************************************************
 * @licstart  The following is the entire license notice for the 
 *  JavaScript code in this page.
 *
 * Copyright (C) 2013  Ophir LOJKINE
 *
 *
 * The JavaScript code in this page is free software: you can
 * redistribute it and/or modify it under the terms of the GNU
 * General Public License (GNU GPL) as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option)
 * any later version.  The code is distributed WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.
 *
 * As additional permission under GNU GPL version 3 section 7, you
 * may distribute non-source (e.g., minimized or compacted) forms of
 * that code without the copy of the GNU GPL normally required by
 * section 4, provided you include this license notice and a URL
 * through which recipients can access the Corresponding Source.
 *
 * @licend
 */
 
(function eraser (){ //Code isolation

	var erasing = false;

	function startErasing (x,y, evt) {
		//Prevent the press from being interpreted by the browser
		evt.preventDefault();
		erasing = true;
		erase(x,y,evt);
	}

	var msg = {
		"type" : "delete",
		"id" : ""
	};
	function erase (x,y, evt){
		/*evt.target is the element over which the mouse is.*/
		if (erasing && evt.target !== Tools.svg) {
			msg.id = evt.target.id;
			Tools.drawAndSend(msg);
		}
	}

	function stopErasing (){
		erasing = false;
	}

	function draw(data) {
		var elem;
		switch(data.type) {
			//TODO: add the ability to erase only some points in a line
			case "delete":
				elem = svg.getElementById(data.id);
				if (elem === null) console.error("Eraser: Tried to delete an element that does not exist.");
				else svg.removeChild(elem);
				break;
			default:
				console.error("Eraser: 'delete' instruction with unknown type. ", data);
				break;
		}
	}

	var svg = Tools.svg;

	Tools.add({ //The new tool
		"name" : "Eraser",
		"listeners" : {
			"press" : startErasing,
			"move" : erase,
			"release" : stopErasing,
		},
		"draw" : draw,
		"mouseCursor" : "crosshair",
	});

})(); //End of code isolation