ShowWindowLevelDlg example for Delphi

procedure TForm1.ShowWindowLevelDlg1Click (Sender: TObject); 
var
   i: L_INT; 
   nRet: L_INT; 
begin
   LEADImage1.GrayScale ( 12 ); {make image 12-bit grayscale}
   LEADImage1.ForceRepaint ( ); 

   LEADDlgColor1.WindowLevelStartColor:= clRed; 
   LEADDlgColor1.WindowLevelEndColor:= clBlue; 
   LEADDlgColor1.LEADImage:= LEADImage1; {assign the main control for processing}
   LEADDlgColor1.DlgFlags:= DLG_WINDOWLEVEL_SHOW_PREVIEW +
                            DLG_WINDOWLEVEL_SHOW_TOOL_ZOOMLEVEL +
                            DLG_WINDOWLEVEL_SHOW_RANGE; 
   LEADImage1.GetMinMaxBits();
   LEADImage1.GetMinMaxVal();

   LEADDlgColor1.WindowLevelLowBit:= LEADImage1.MinBit; 
   LEADDlgColor1.WindowLevelHighBit:= LEADImage1.MaxBit; 
   LEADDlgColor1.WindowLevelLow:= LEADImage1.MinVal; 
   LEADDlgColor1.WindowLevelHigh:= LEADImage1.MaxVal; 
   LEADDlgColor1.WindowLevelFactor:= 10; 
   LEADDlgColor1.WindowLevelFlags:= FILLLUT_INSIDE + FILLLUT_LOGARITHMIC; 

   nRet:= LEADDlgColor1.ShowWindowLevelDlg ( Self ); 
   if ( nRet = SUCCESS_DLG_OK ) then
   begin
      LEADImage1.WindowLevelBitmap:= false; 
      LEADImage1.LevelLowBit:= LEADDlgColor1.WindowLevelLowBit; 
      LEADImage1.LevelHighBit:= LEADDlgColor1.WindowLevelHighBit; 
      for i:= 0 to LEADDlgColor1.WindowLevelLUTLength -1 do
      begin
         LEADImage1.LevelLUT[i]:= LEADDlgColor1.WindowLevelLUT [i]; 
      end; 
      LEADImage1.WindowLevel ( ); 
   end; 
end;