Rem ************************************ 
Rem *        AMOS Example 6.3          * 
Rem *         Rubber banding           * 
Rem *    (c) Mandarin / Jawx 1990      * 
Rem ************************************ 
Rem
Rem Main loop
Do 
   GROWBOX
   Locate 0,0 : Print "Starting coordinates are",GX1;"  ";GY1;"   ";
   Locate 0,1 : Print "Ending   coordinates are",GX2;"  ";GY2;"   ";
Loop 
Procedure GROWBOX
   Rem A simple procedure to create a rubber banding effect 
   Rem Define coordinates as GLOBAL 
   Shared GX1,GX2,GY1,GY2
   Rem Set up XOR mode
   Gr Writing 2
   Rem Rubber band
   Repeat 
      Rem Wait until the left mouse button is pressed  
      If Mouse Key=1
         Rem Get coordinates of top corner
         GX1=X Screen(X Mouse) : GY1=Y Screen(Y Mouse) : GX2=GX1 : GY2=GY1
         While Mouse Key=1
            Rem Drag box around with the mouse 
            Box GX1,GY1 To GX2,GY2
            GX2=X Screen(X Mouse) : GY2=Y Screen(Y Mouse)
            Box GX1,GY1 To GX2,GY2
         Wend 
         Box GX1,GY1 To GX2,GY2 : GRABBED=True
         Rem Make GX1,GY1 the coords of the TOP left corner   
         If GX1>GX2 : T=GX1 : GX1=GX2 : GX2=T : End If 
         If GY1>GY2 : T=GY1 : GY1=GY2 : GY2=T : End If 
      End If 
      Rem Wait until mouse button is released
   Until GRABBED
   Rem Restore writing mode to normal 
   Gr Writing 1
End Proc