private static SvgTransform CreateRotateTransformationFromArgs(string args)
{
// rotate(<rotate-angle> [<cx> <cy>]), which specifies a rotation by <rotate-angle> degrees about a given point.
//
// If optional parameters <cx> and <cy> are not supplied, the rotate is about the origin of the current user coordinate system.
// The operation corresponds to the matrix [cos(a) sin(a) -sin(a) cos(a) 0 0].
//
// If optional parameters<cx> and<cy> are supplied, the rotate is about the point(cx, cy).
// The operation represents the equivalent of the following specification:
// translate(< cx >, < cy >) rotate(< rotate - angle >) translate(-< cx >, -< cy >).
var split = SplitStringOfNumbers(args);
if (split.Length != 1 && split.Length != 3)
{
throw new Exception($"Invalid rotate transformation arguments '{args}'");
}
var angle = float.Parse(split[0]);
var cx = split.Length > 1 ? (float?)float.Parse(split[1]) : null;
var cy = split.Length > 1 ? (float?)float.Parse(split[2]) : null;
var matrix = SvgMatrix.CreateRotate(angle, cx, cy);
return(new SvgTransform(SvgTransformType.Rotate, matrix, angle));
}
