Simple class to represent a color in RGBA.

class Color {
 int r, g, b, a;

 /**
  * Creates a [Color] from a hex string.
  */
 Color.fromHex(String hex, [this.a = 255]) {
   var rgb = hexToRgb(hex);
   r = rgb[0];
   g = rgb[1];
   b = rgb[2];
 }
 /**
  * Creates a [Color] from RGB values.
  */
 Color.fromRgb(this.r, this.g, this.b, [this.a = 255]);

 /**
  * Creates a list of the RGBA values.
  */
 List<int> toArray() => [r, g, b, a];
 /**
  * Creates a RGB string.
  */
 String toRgb() => "rgb($r,$g,$b)";
 /**
  * Creates a RGBA string.
  */
 String toRgba() => "rgba($r,$g,$b,$a)";
 /**
  * Creates a hex string.
  */
 String toHex() => rgbToHex(r, g, b);
 /**
  * Creates a list of HSL values.
  */
 List<double> toHsl() => rgbToHsl(r, g, b);
 /**
  * Creates a list of HSV values.
  */
 List<double> toHsv() => rgbToHsv(r, g, b);
}