colorToSvgColor function
Implementation
String? colorToSvgColor(Color? color) {
if (color == null) return null;
if (color.a == 0) return "transparent";
int rgb32 = color.toARGB32() & 0x00FFFFFF;
String hex = rgb32.toRadixString(16).padLeft(6, '0');
return '#$hex';
}