code: function _rotateCanvas(ctx, params, transforms) {
  
  	// Get conversion factor for radians
  	params._toRad = (params.inDegrees ? (PI / 180) : 1);
  
  	// Rotate canvas using shape as center of rotation
  	ctx.translate(params.x, params.y);
  	ctx.rotate(params.rotate * params._toRad);
  	ctx.translate(-params.x, -params.y);
  
  	// If transformation data was given
  	if (transforms) {
  		// Update transformation data
  		transforms.rotate += (params.rotate * params._toRad);
  	}
  }
docs: Rotates canvas (internal)