Reference TAdvancedColorDialog

  TAdvancedColorDialog = class(TComponent)
  public
    { Create a dialog with black as the color }
    constructor Create(AOwner: TComponent); override;
    { Show the dialog returning true if the user chose a color }
    function Execute: Boolean;
    { The color including alpha }
    property ColorValue: TColorB read GetColorValue write SetColorValue;
  published
    { The color without alpha }
    property Color: TColor read FColor write FColor default clBlack;
    { The alpha of the color from 0 for transparent to 255 for opaque }
    property Alpha: Byte read FAlpha write FAlpha default 255;
    { The dialog caption, or the default caption when empty }
    property Title: string read FTitle write FTitle;
    { The file where custom colors are saved, or a file in the application
      config directory when empty }
    property CustomColorsFile: string read FCustomColorsFile write FCustomColorsFile;
  end;