使用javascript解析SVG变换属性

Question

假设我们有一个SVG转换字符串:

transform = "translate(6,5),scale(3,3)";

是否有一个灵活的正则表达式函数,我们可以用它来解析可用的东西？

Answer 1

这里有一段漂亮的小代码片段,可以为您提供所需的代码,如果您打算解析的字符串具有不同数量的参数,它应涵盖大多数情况:

function parse (a)
{
    var b={};
    for (var i in a = a.match(/(\w+\((\-?\d+\.?\d*e?\-?\d*,?)+\))+/g))
    {
        var c = a[i].match(/[\w\.\-]+/g);
        b[c.shift()] = c;
    }
    return b;
}

运行这个

parse('translate(6,5),scale(3,3.5),a(1,1),b(2,23,-34),c(300)');

会导致这个:

{
    translate: [ '6', '5' ],
    scale: [ '3', '3.5' ],
    a: [ '1', '1' ],
    b: [ '2', '23', '-34' ],
    c: [ '300' ]
}

Answer 2

假设您正在浏览器中运行，还可以使用SVG DOM来解析和解码转换字符串。

var svgns = "http://www.w3.org/2000/svg";

function getTransformList(transformStr)
{
  // Create a fake <rect> element to set the transform to
  var rect = document.createElementNS(svgns, "rect");
  rect.setAttribute("transform", transformStr);
  // Use the DOM to get the list of decoded transforms
  dumpTransform(rect.transform.baseVal);
}

function dumpTransform(transformList)
{
  for (var i=0; i<transformList.length; i++)
  {
    var transform = transformList[i];
    var m = transform.matrix;
    switch (transform.type)
    {
      case 2:
        console.log("translate("+m.e+","+m.f+")");
        break;
      case 3:
        console.log("scale("+m.a+","+m.d+")");
        break;
      case 4:
        console.log("rotate("+transform.angle+")");
        // TODO need to also handle rotate(angle, x, y) form
        break;
      case 5:
        // TODO skewX()
        break;
      case 6:
        // TODO skewY(()
        break;
      case 1:
      default:
        console.log("matrix("+m.a+","+m.b+","+m.c+","+m.d+","+m.e+","+m.f+")");
        break;
    }
  }
}

getTransformList("translate(6,5),scale(3,3)");