piskel/js/drawingtools/BaseTool.js

/*
 * @provide pskl.drawingtools.BaseTool
 *
 * @require pskl.utils
 */
(function() {
	var ns = $.namespace("pskl.drawingtools");

	ns.BaseTool = function() {};

	ns.BaseTool.prototype.applyToolAt = function(col, row, frame) {};
	
	ns.BaseTool.prototype.moveToolAt = function(col, row, frame) {};

	ns.BaseTool.prototype.releaseToolAt = function(col, row, frame) {};

	/**
	 * Bresenham line algorihtm: Get an array of pixels from
	 * start and end coordinates.
	 *
	 * http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
	 * http://stackoverflow.com/questions/4672279/bresenham-algorithm-in-javascript
	 *
	 * @private
	 */
	ns.BaseTool.prototype.getLinePixels_ = function(x0, x1, y0, y1) {
		
		var pixels = [];
		var dx = Math.abs(x1-x0);
	   	var dy = Math.abs(y1-y0);
	   	var sx = (x0 < x1) ? 1 : -1;
	   	var sy = (y0 < y1) ? 1 : -1;
	   	var err = dx-dy;

	   	while(true){

	    	// Do what you need to for this
	    	pixels.push({"col": x0, "row": y0});

		    if ((x0==x1) && (y0==y1)) break;
		    var e2 = 2*err;
		    if (e2>-dy){
		    	err -= dy;
		    	x0  += sx;
		    }
		    if (e2 < dx) {
		    	err += dx;
		    	y0  += sy;
		    }
	    }
	    return pixels;
     };
})();