D3.js封装文本实现自动换行和旋转平移等功能

function appendMultiText(container, str, posX, posY, width, fontsize, fontfamily){
			
			if( arguments.length < 6){
				fontsize = 14;
			}		
			
			if( arguments.length < 7){
				fontfamily = "simsun, arial";
			}
			
			//获取分割后的字符串
			var strs = splitByLine(str,width,fontsize);
			
			var mulText = container.append("text")
				.attr("x",posX)
				.attr("y",posY)
				.style("font-size",fontsize)
				.style("font-family",fontfamily);
				
			mulText.selectAll("tspan")
				.data(strs)
				.enter()
				.append("tspan")
				.attr("x",mulText.attr("x"))
				.attr("dy","1em")
				.text(function(d){
					return d;
				});
				
			return mulText;
			
			function splitByLine(str,max,fontsize){
				var curLen = 0;
				var result = [];
				var start = 0, end = 0;
				for(var i=0;i<str.length;i++){
					var code = str.charCodeAt(i);
					var pixelLen = code > 255 ? fontsize : fontsize/2;
					curLen += pixelLen;
					if(curLen > max){
						end = i;
						result.push(str.substring(start,end));
						start = i;
						curLen = pixelLen;
					}
					if( i === str.length - 1 ){
						end = i;
						result.push(str.substring(start,end+1));
					}
				}
				return result;
			}
}

<script src="multext.js" charset="utf-8"></script> 

<script src="http://d3js./d3.v3.min.js" charset="utf-8"></script> 

appendMultiText( 
  container,     //文本的容器，可以是<svg>或<g>  
  str,        //字符串 
  posX,        //文本的x坐标 
  posY,        //文本的y坐标 
  width,       //每一行的宽度，单位为像素 
  fontsize,      //文字的大小（可省略），默认为 14 
  fontfamily     //文字的字体（可省略），默认为 simsun, arial 
) 

var width = 300; 
var height = 300; 
 
var svg = d3.select("body") 
      .append("svg") 
      .attr("width",width) 
      .attr("height",height); 

var str = "青青子衿，悠悠我心，但为君故，沉吟至今。";       
             
appendMultiText(svg,str,30,100,120,20,"simsun"); 

var str = "青青子衿，悠悠我心，但为君故，沉吟至今。";       
             
var multext = appendMultiText(svg,str,30,100,120,20,"simsun"); 
         
multext.attr("transform","rotate(-20)"); 

var g = svg.append("g"); 
             
var multext = appendMultiText(g,str,30,100,120);