en/builder/src/zrender/tool/transformPath.js

import PathProxy from '../core/PathProxy';
import { applyTransform as v2ApplyTransform } from '../core/vector';
var CMD = PathProxy.CMD;
var points = [[], [], []];
var mathSqrt = Math.sqrt;
var mathAtan2 = Math.atan2;
export default function (path, m) {
  var data = path.data;
  var cmd;
  var nPoint;
  var i;
  var j;
  var k;
  var p;
  var M = CMD.M;
  var C = CMD.C;
  var L = CMD.L;
  var R = CMD.R;
  var A = CMD.A;
  var Q = CMD.Q;

  for (i = 0, j = 0; i < data.length;) {
    cmd = data[i++];
    j = i;
    nPoint = 0;

    switch (cmd) {
      case M:
        nPoint = 1;
        break;

      case L:
        nPoint = 1;
        break;

      case C:
        nPoint = 3;
        break;

      case Q:
        nPoint = 2;
        break;

      case A:
        var x = m[4];
        var y = m[5];
        var sx = mathSqrt(m[0] * m[0] + m[1] * m[1]);
        var sy = mathSqrt(m[2] * m[2] + m[3] * m[3]);
        var angle = mathAtan2(-m[1] / sy, m[0] / sx); // cx

        data[i] *= sx;
        data[i++] += x; // cy

        data[i] *= sy;
        data[i++] += y; // Scale rx and ry
        // FIXME Assume psi is 0 here

        data[i++] *= sx;
        data[i++] *= sy; // Start angle

        data[i++] += angle; // end angle

        data[i++] += angle; // FIXME psi

        i += 2;
        j = i;
        break;

      case R:
        // x0, y0
        p[0] = data[i++];
        p[1] = data[i++];
        v2ApplyTransform(p, p, m);
        data[j++] = p[0];
        data[j++] = p[1]; // x1, y1

        p[0] += data[i++];
        p[1] += data[i++];
        v2ApplyTransform(p, p, m);
        data[j++] = p[0];
        data[j++] = p[1];
    }

    for (k = 0; k < nPoint; k++) {
      var p = points[k];
      p[0] = data[i++];
      p[1] = data[i++];
      v2ApplyTransform(p, p, m); // Write back

      data[j++] = p[0];
      data[j++] = p[1];
    }
  }
}