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TDBAdvTrackBar
How to draw a custom tickmark at thumb position
How to draw a custom tickmark at thumb position
To draw a custom tickmark at thumb position, drop a default TAdvTrackBar on the form and add following code:
procedure TForm2.AdvTrackBar1Change(Sender: TObject); begin AdvTrackBar1.Invalidate; end; procedure TForm2.AdvTrackBar1DrawTick(Sender: TObject; Canvas: TCanvas; Location: TPoint; Position: Integer; TickPos: TTickMark; var Length: Integer; var Color, TextColor: TColor; var Text: string; var DefaultDraw: Boolean); begin if Position = AdvTrackBar1.Position then begin DefaultDraw := false; Canvas.MoveTo(Location.X, Location.Y); Canvas.Pen.Color := cLRed; Canvas.Pen.Width := 3; Canvas.LineTo(Location.X, Location.Y + 10); Canvas.Pen.Width := 1; Canvas.Pen.Color := clBlack; end; end;
This will draw at thumb position a think red tickmark: