从svg matix获取旋转角度、缩放比例、偏移量信息

var m1={"a":-8.80408e-16,"b":-2.05409,"c":2.05409,"d":-8.80408e-16,"e":154.638,"f":465.722}
 m={"a":-2.05409,"b":0,"c":0,"d":-2.05409,"e":656.608,"f":880.401}
 

function decomposeMatrix(m) {
  var E = (m.a + m.d) / 2
  var F = (m.a - m.d) / 2
  var G = (m.c + m.b) / 2
  var H = (m.c - m.b) / 2

  var Q = Math.sqrt(E * E + H * H);
  var R = Math.sqrt(F * F + G * G);
  var a1 = Math.atan2(G, F);
  var a2 = Math.atan2(H, E);
  var theta = (a2 - a1) / 2;
  var phi = (a2 + a1) / 2;

  // The requested parameters are then theta, 
  // sx, sy, phi,
  return {
    translateX: m.e,
    translateY: m.f,
    rotate: -phi * 180 / Math.PI,
    scaleX: Q + R,
    scaleY: Q - R,
    skew: -theta * 180 / Math.PI
  };
}

 function deltaTransformPoint(matrix, point)  {

        var dx = point.x * matrix.a + point.y * matrix.c + 0;
        var dy = point.x * matrix.b + point.y * matrix.d + 0;
        return { x: dx, y: dy };
    }


function decomposeMatrix1(matrix) {

        // calculate delta transform point
        var px = deltaTransformPoint(matrix, { x: 0, y: 1 });
        var py = deltaTransformPoint(matrix, { x: 1, y: 0 });

        // calculate skew
        var skewX = ((180 / Math.PI) * Math.atan2(px.y, px.x) - 90);
        var skewY = ((180 / Math.PI) * Math.atan2(py.y, py.x));

        return {

            translateX: matrix.e,
            translateY: matrix.f,
            scaleX: Math.sqrt(matrix.a * matrix.a + matrix.b * matrix.b),
            scaleY: Math.sqrt(matrix.c * matrix.c + matrix.d * matrix.d),
            skewX: skewX,
            skewY: skewY,
            rotation: skewX // rotation is the same as skew x
        };        
    }

alert(decomposeMatrix1(m))