jtopo

jtopo文本換行
擴展prototype屬性：

          CanvasRenderingContext2D.prototype.wrapText = function(str,x,y){
            var index = str.indexOf('-');
            str2= str.substr(index+1,str.length);
            str1= str.substr(0,index);
    var textArray = new Array(str1,str2);
    if(textArray==undefined||textArray==null)return false;
    var rowCnt = textArray.length;
    var i = 0,imax  = rowCnt,maxLength = 0;maxText = textArray[0];
    for(;i<imax;i++){
        var nowText = textArray[i],textLength = nowText.length;
        if(textLength >=maxLength){
            maxLength = textLength;
            maxText = nowText;
        }
    }
    var maxWidth = this.measureText(maxText).width;
    var lineHeight = this.measureText("元").width;
    x-= lineHeight*2;
    for(var j= 0;j<textArray.length;j++){
        var words = textArray[j];
        this.fillText(words,x,y);
        y+= lineHeight;
    }
  };    

節點調用：

node.paintText = function(a){
a.beginPath(),
a.font = this.font,
a.wrapText(this.text,this.height/2,this.height);
a.closePath()   
                }

歡迎轉載，請註明出處。