Reference TDesktopTheme

  TDesktopTheme = class(TCanvasTheme)
  protected
    { The color of a theme color as $RRGGBB }
    function Palette(Widget: TWidget; Color: TThemeColor): LongWord; virtual; abstract;
    function CaptionHeight: Float; virtual; abstract;
    function ButtonHeight: Float; virtual; abstract;
    function ThumbSize: TSizeF; virtual; abstract;
    function WindowRadius: Float; virtual; abstract;
    { The thickness of the window frame, X for the sides and Y for the bottom }
    function WindowBorder: TSizeF; virtual;
    { A $RRGGBB color faded by the opacity of the widget }
    function Shade(Widget: TWidget; RGB: LongWord; Alpha: Float = 1): TColorF;
    { Set up the gradient brush to run down or across a rectangle }
    procedure VertGradient(const R: TRectF; const Top, Bottom: TColorF);
    procedure HorzGradient(const R: TRectF; const Left, Right: TColorF);
    procedure CheckMark(const R: TRectF; const C: TColorF; Width: Float);
    function CheckRect(Widget: TCheckBox; Size: Float): TRectF;
    procedure CheckCaption(Widget: TCheckBox; Size: Float);
    procedure SpinArrows(Widget: TSpinBox; const R: TRectF; const C: TColorF);
    procedure GripLines(const R: TRectF; Horizontal: Boolean; const C: TColorF);
    procedure LoadFonts(const FontName, FontFile, TitleName, TitleFile: string);
    function GlyphSize: Float; override;
    procedure Init(Canvas: ICanvas); override;
    procedure DrawGlyphButton(Widget: TGlyphButton); override;
    procedure DrawGlyphImage(Widget: TGlyphImage); override;
    procedure PostDrawSpinBox(Widget: TSpinBox); override;
    procedure DrawLabel(Widget: TLabel); override;
    procedure DrawContainer(Widget: TContainerWidget); override;
  public
    function CalcColor(Widget: TWidget; Color: TThemeColor): TColorF; override;
    function CalcSize(Widget: TWidget; Part: TThemePart): TSizeF; override;
  end;