function getTextWidth(text, font) {
	        font = font || DEFAULT_FONT;
	        var key = text + ':' + font;
	        if (textWidthCache[key]) {
	            return textWidthCache[key];
	        }

	        var textLines = (text + '').split('\n');
	        var width = 0;

	        for (var i = 0, l = textLines.length; i < l; i++) {
	            // textContain.measureText may be overrided in SVG or VML
	            width = Math.max(textContain.measureText(textLines[i], font).width, width);
	        }

	        if (textWidthCacheCounter > TEXT_CACHE_MAX) {
	            textWidthCacheCounter = 0;
	            textWidthCache = {};
	        }
	        textWidthCacheCounter++;
	        textWidthCache[key] = width;

	        return width;
	    }
@public
@param {string} text
@param {string} font
@return {number} width