My about box is transparent. You can change from here. It's not the best

way, but works fine.

ABOUTBOX FORM

-insert a TImage with AllClient called img.

MAIN FORM

procedure CallAboutBox;

var

 screenshoot: TBitmap;

begin

 screenshoot := TBitmap.Create;

 fAbout := TfAbout.create(self);

 DrawBack;

 fAbout.show;

 screenshoot.free;

end;

procedure DrawBack;

type

 PRGBArray = ^TRGBArray;

 TRGBArray = array[0..1000000] of TRGBTriple;

var

 DC: hDC;

 ScreenWidth, ScreenHeight: Integer;

 SL: PRGBArray;

 X, Y: Integer;

const

 FTransparency = 30;  // % of transparency

 FTranspColor = clGray;  // color to be merged

begin

 ScreenWidth := GetSystemMetrics(sm_CXScreen);

 ScreenHeight := GetSystemMetrics(sm_CYScreen);

 ScreenShoot.Width := ScreenWidth;

 ScreenShoot.Height := ScreenHeight;

 ScreenShoot.PixelFormat := pf24bit;

 // get screen image

 DC := GetDC(0);

 BitBlt(ScreenShoot.Canvas.Handle, 0, 0,

        ScreenWidth, ScreenHeight, DC, 0, 0, SrcCopy);

 ReleaseDC(0, DC);

 for Y := 0 to ScreenHeight - 1 do begin

   SL := ScreenShoot.ScanLine[Y];

   for X := 0 to ScreenWidth - 1 do

     try

      SL[X].rgbtRed := (FTransparency * SL[X].rgbtRed + (100 -

FTransparency) * GetRValue(FTranspColor)) div 100;

      SL[X].rgbtGreen := (FTransparency * SL[X].rgbtGreen + (100 -

FTransparency)* GetGValue(FTranspColor)) div 100;

      SL[X].rgbtBlue := (FTransparency * SL[X].rgbtBlue + (100 -

FTransparency) * GetBValue(FTranspColor)) div 100;

     except

     end;

 end;

 with fAbout do begin

   X :=  ((ScreenWidth - width) div 2) + img.Left;

   Y :=  ((Screenheight - height) div 2) + img.Top;

   if WindowState = wsNormal then

     case BorderStyle of

        bsSingle,

        bsDialog: begin

                   inc(X, GetSystemMetrics(sm_CXDlgFrame));

                   inc(Y, GetSystemMetrics(sm_CYDlgFrame));

                  end;

        bsSizeable: begin

                     inc(X, GetSystemMetrics(sm_CXFrame));

                     inc(Y, GetSystemMetrics(sm_CYFrame));

                    end;

        bsToolWindow,

        bsSizeToolWin: begin

                        inc(X, GetSystemMetrics(sm_CXBorder));

                        inc(Y, GetSystemMetrics(sm_CYBorder));

                       end;

      end;

   if BorderStyle <> bsNone then

     inc(Y, GetSystemMetrics(sm_CYCaption));

   BitBlt(img.Canvas.Handle, 0, 0, img.Width, img.Height,

          ScreenShoot.Canvas.Handle, x, y, SrcCopy);

 end;

end;