// Draw two images onto a bitmap above
// Image 1 is centered within the top 30% of the bitmap. Image 2 is centered within the bottom 70% of the bitmap
const
  // Size to draw image 1
  Image_1_Max_Width  = 900;
  Image_1_Max_Height = 300;                 // 30% of output image height

  // Size to draw image 2
  Image_2_Max_Width  = Image_1_Max_Width;
  Image_2_Max_Height = 700;                 // 70% of output image height

  // Size of output image
  Image_Out_Width    = Image_1_Max_Width;
  Image_Out_Height   = Image_1_Max_Height + Image_2_Max_Height;

  BG_Color           = clWhite;
var
  bmpOut, bmp1, bmp2 : TIEBitmap;
  rct1, rct2: TRect;
begin
  bmp1 := TIEBitmap.Create();
  bmp2 := TIEBitmap.Create();
  bmpOut := TIEBitmap.Create( Image_Out_Width, Image_Out_Height, BG_Color );
  try
    bmp1.Read( 'D:\im.jpg' );
    bmp2.Read( 'D:\IMG_20200906_190157.jpg' );

    // Draw bmp1 at top of image within allowed space (while maintaing AR)
    rct1 := GetImageRectWithinArea( bmp1.Width, bmp1.Height,
                                    Image_1_Max_Width, Image_1_Max_Height );
    bmp1.StretchRectTo( bmpOut,
                        rct1.Left, rct1.Top, RectWidth( rct1 ), RectHeight( rct1 ),
                        0, 0, bmp1.Width, bmp1.Height,
                        rfLanczos3 );

    // Draw bmp2 below bmp1 within allowed space (while maintaing AR)
    rct2 := GetImageRectWithinArea( bmp2.Width, bmp2.Height,
                                    Image_2_Max_Width, Image_2_Max_Height );
    bmp2.StretchRectTo( bmpOut,
                        rct2.Left, Image_1_Max_Height + rct2.Top, RectWidth( rct2 ), RectHeight( rct2 ),
                        0, 0, bmp2.Width, bmp2.Height,
                        rfLanczos3 );

    // Show in our TImageEnView
    ImageEnView1.Assign( bmpOut );

  finally
    bmp1 .Free;
    bmp2 .Free;
    bmpOut.Free;
  end;
end;