如何确定SVG文本框的宽度或在'x'字符后强制换行？
使用该getBBox()方法，一次向一个文本对象添加一个单词。如果宽度过大，则需要添加换行符。
var a = Raphael(500, 500);
var b = a.text(100, 100).attr('text-anchor', 'start');
var maxWidth = 100;
var content = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis nec semper mauris. Sed gravida augue feugiat nulla ultrices efficitur. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Sed sit amet lobortis eros, et lobortis diam. Aenean arcu velit, condimentum eu lacus in, dignissim bibendum odio. Mauris ultricies nunc et lorem bibendum dignissim. Ut porttitor purus vitae diam efficitur ultrices. Integer dignissim efficitur lorem, non vehicula diam scelerisque at ";
var w = content.split(" ");
var tempText = "";
for (var i = 0; i < w.length; i++) {
b.attr("text", tempText + " " + words[i]);
if (b.getBBox().width > maxWidth) {
tempText += "\n" + words[i];
} else {
tempText += " " + words[i];
}
}
b.attr("text", tempText.substring(1));