operator + method
Implementation
Color operator +(dynamic v) {
if (v is double) {
return Color(r: r + v, g: g + v, b: b + v);
} else if (v is Color) {
return Color(r: r + v.r, g: g + v.g, b: b + v.b);
} else {
throw 'Color only support addition by double or Color';
}
}