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 should be the element over which the mouse is...
		var target = evt.target;
		if (evt.type === "touchmove") {
			// ... the target of touchmove events is the element that was initially touched,
			// not the one **currently** being touched
			var touch = evt.touches[0];
			target = document.elementFromPoint(touch.clientX, touch.clientY);
		}
		if (erasing && target !== Tools.svg) {
			msg.id = 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",
		"icon": "❌",
		"shortcut": "e",
		"listeners": {
			"press": startErasing,
			"move": erase,
			"release": stopErasing,
		},
		"draw": draw,
		"mouseCursor": "crosshair",
	});

})(); //End of code isolation