Flat/Hot track effect for components

Problem/Question/Abstract:

How can I add the hot track effect to my component?

Answer:

If you want to add a useful feature to your component (like URL in html or PageControl/TabControl.HotTrack) you must handle the CM_MOUSEENTER and CM_MOUSELEAVE messages:

type
  TyourControl = class(TDescControl)
  private
    { Private declarations }
    FLinkFont: TFont;
    FPassiveFont: TFont;

    procedure CMMouseEnter(var Msg: TMessage); message CM_MOUSEENTER;
    procedure CMMouseLeave(var Msg: TMessage); message CM_MOUSELEAVE;
  end;

implementation

procedure TyourControl.CMMouseEnter(var Msg: TMessage);
begin
  //Change color when mouse is over control
  Font.Assign(FLinkFont);
end;

procedure TyourControl.CMMouseLeave(var Msg: TMessage);
begin
  //Change color when mouse leaves control
  Font.Assign(FPassiveFont);
end;

As example, you can view a sources of the TURLLabel and/or THighLightLabel components on my site (http://www.geocities.com/mshkolnik).