DetectGraph procedure

  DECLARATION:  DetectGraph(var GraphDriver, GraphMode : Integer);

      PURPOSE:  Determines which graphics driver and mode value that
                can be passed to InitGraph, which will then load the
                correct driver.

         UNIT:  Graph

      REMARKS:  The procedure InitGraph will call DetectGraph if no
                values are given.  The following modes are predefined in the
                Graph unit:

 CGA0       = 0; 320 X 200 Palette 0: LightGreen, LightRed, Yellow; 1 Page
 CGA1       = 1; 320 X 200 Palette 1: LightCyan, LightMagenta, White; 1 Page
 CGA2       = 2; 320 X 200 Palette 2: Green, Red, Brown; 1 Page
 CGA3       = 3; 320 X 200 Palette 3: Cyan, Magenta, LightGray; 1 Page
 CGAHi      = 4; 640 X 200 1 Page
 MCGAC0     = 0; 320 X 200 Palette 0: LightGreen, LightRed, Yellow; 1 Page
 MCGAC1     = 1; 320 X 200 Palette 1: LightCyan, LightMagenta, White; 1 Page
 MCGAC2     = 2; 320 X 200 Palette 2: Green, Red, Brown; 1 Page
 MCGAC3     = 3; 320 X 200 Palette 3: Cyan, Magenta, LightGray; 1 Page
 MCGAMed    = 4; 640 X 200 1 Page
 MCGAHi     = 5; 640 X 480 1 Page
 EGALo      = 0; 640 X 200 4 Pages
 EGAHi      = 1; 640 X 325 16 Colors, 2 Pages
 EGA64Lo    = 0; 640 X 200 16 Colors, 1 Page
 EGA64Hi    = 1; 640 X 315 4 Colors, 1 Page
 HercMonoHi = 0; 720 X 348 2 Pages
 ATT400C0   = 0; 320 X 200 Palette 0: LightGreen, LightRed, Yellow; 1 Page
 ATT400C1   = 1; 320 X 200 Palette 1: LightCyan, LightMagenta, White; 1 Page
 ATT400C2   = 2; 320 X 200 Palette 2: Green, Red, Brown; 1 Page
 ATT400C3   = 3; 320 X 200 Palette 3: Cyan, Magenta, LightGray; 1 Page
 ATT400Med  = 4; 640 X 200 1 Page
 ATT400Hi   = 5; 640 X 400 1 Page
 VGALo      = 0; 640 X 200 16 Colors; 4 Pages
 VGAMed     = 1; 640 X 350 16 Colors; 2 Pages
 VGAHi      = 2; 640 X 480 16 Colors; 1 Page
 PC3270Hi   = 0; 720 X 350 1 Page
 IBM8514Lo  = 0; 640 X 480 256 Colors
 IBM8514Hi  = 0; 1024 X 768 256 Colors