Getting the MaxLen parameter to use with MinimizeName - delphi

Question

I am trying to put a very long filename on a TLabel using the MinimizeName function from Vcl.FileCtrl unit but I can't figure out how to get the MaxLen parameter used by the function
If I hardcode a value I can see a valid result. But since the form can be resized I would like it to be dynamic = changing on resize event.
Some of the things I have tried is
lblLicenseFile.Width // string is too long
lblLicenseFile.Width - 10 //string is too long
Trunc(lblLicenseFile.Width / lblLicenseFile.Font.Size) // string is very short
There must be some method of calculating this number of pixels
MinimizeName(const Filename: TFileName; Canvas: TCanvas; MaxLen: Integer): TFileName;
MaxLen is the lenght, in pixels, available for drawing the file name on the canvas.

Answer 1

To let the label control automatically shorten path, you can set the AutoSize property to False and the EllipsisPosition property to epPathEllipsis if you're using a recent version of Delphi.

Answer 2

To get rid of dependencies of form resizing, resize could also happen if you using e.g. splitters, you can override the CanResize Event to adapt your caption.
as example:
unit Unit3;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TLabel = Class(StdCtrls.TLabel)
private
FFullCaption: String;
procedure SetFullname(const Value: String);
published
function CanResize(var NewWidth, NewHeight: Integer): Boolean; override;
property FullCaption: String read FFullCaption Write SetFullname;
End;
TForm3 = class(TForm)
FileNameLabel: TLabel;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private-Deklarationen }
public
{ Public-Deklarationen }
end;
var
Form3: TForm3;
implementation
uses FileCtrl;
{$R *.dfm}
procedure TForm3.Button1Click(Sender: TObject);
begin
FileNameLabel.FullCaption := 'C:\ADirectory\ASubDirectory\ASubSubDirectory\AFileN.ame'
end;
{ TLabel }
function TLabel.CanResize(var NewWidth, NewHeight: Integer): Boolean;
begin
inherited;
if Assigned(Parent) then
Caption := MinimizeName(FFullCaption, Canvas, NewWidth)
end;
procedure TLabel.SetFullname(const Value: String);
begin
FFullCaption := Value;
Caption := MinimizeName(FFullCaption, Canvas, Width)
end;
end.