How to Make MOUSE CALLs in Hercules Graphics Mode, SCREEN 3 (30856)

MORE INFORMATION

The following information applies to QuickBasic Versions 4.00, 4.00b, and 4.50 and Microsoft Basic Compiler Versions 6.00 and 6.00b running under MS-DOS.

When making CALLs to the Microsoft Mouse driver on a computer with a Hercules Monochrome Graphics Adapter, do the following:

1. In the AUTOEXEC.BAT file, invoke the Microsoft MOUSE.COM driver before the QBHERC.COM or MSHERC.COM Hercules Graphics driver. If QBHERC or MSHERC is mistakenly loaded first, the Hercules graphics cursor appears as several small horizontal (broken) lines in the graphics screen (or it does not appear at all), and the graphics drawing boundaries are confined to 640 x 200 pixels. (Normal SCREEN 3 resolution is 720 x 348.)
   
   MSHERC.COM is shipped with QuickBasic Version 4.50. QBHERC.COM is shipped with Microsoft QuickBasic Versions 4.00 and 4.00b and with Microsoft Basic Compiler Versions 6.00 and 6.00b.
2. Perform one of the following steps, but not both:
   
   
   1. Start QB.EXE by typing QB /L MOUSE to load the Quick Library MOUSE.QLB into memory. You can use LINK /Q to make MOUSE.QLB from the MOUSE.LIB that comes on a disk along with the "Microsoft Mouse Programmer's Reference Guide." This guide can be ordered by returning the card in the Microsoft Mouse package. or
      
      
   2. Start QB.EXE by typing QB /L QB.QLB and use CALL INTERRUPT or CALL INT86OLD to access the mouse driver. To find out how to use CALL INTERRUPT or CALL INT86OLD to program the mouse, search for a separate article with the following words: INTERRUPT and INT86OLD and 51 and MOUSE
3. To tell the mouse driver that you are in CRT Page 0, define the segment address (DEF SEG) at hex 40 and POKE a 6 into offset hex 49. You must store 5 into memory offset hex 49 to use CRT Page 1. The following is an example:

         DEF SEG = &H40
         POKE &H49, 6          ' CRT page 0
         DEF SEG
   						

4. Call the mouse function 0 to initialize, as follows:

         CALL mouse(0,0,0,0)     '  initialize mouse
   						

5. Put the card into the graphics mode (i.e., change to SCREEN mode 3), as follows:

         SCREEN 3, , 0, 0
   						

6. CALL the mouse to turn the mouse cursor on, as follows:

         CALL mouse(1, 0, 0, 0)     '  turn mouse cursor on
   						

QuickBasic Versions 3.00 and earlier do not support Hercules Monochrome Graphics SCREEN 3.

The techniques explained in this article do not work under the DOS box (real mode) of MS OS/2 (nor do they work in protected mode, which requires OS/2 MOU... API function calls from Microsoft Basic Compiler 6.00 or 6.00b to program the mouse). OS/2 normally loads its own mouse driver for the DOS box, and even if this driver isn't loaded, OS/2 still reserves interrupt 33 for itself. If you install MOUSE.COM in the DOS box, OS/2 will tell you that the interrupt is owned by the system, and although a program can display the mouse cursor on Hercules SCREEN 3 (such as the Code Example below), the pointer will not move. You cannot program the mouse in Hercules graphics SCREEN 3 in the DOS box (real mode) of MS OS/2. You can, however, program the mouse in other graphics screen modes in the DOS box of OS/2.

Code Example

The following example can be compiled with QuickBasic Versions 4.00, 4.00b, and 4.50 and with Microsoft Basic Compiler Versions 6.00 and 6.00b in MS-DOS:

DEFINT A-Z
DEF SEG = &H40
POKE &H49, 6               ' CRT page 0
DEF SEG
CALL mouse(0, 0, 0, 0)     ' Initialize Mouse
SCREEN 3, , 0, 0           ' Switch to Hercules Graphics mode, page 0

m1 = 1
CALL mouse(m1, m2, m3, m4)   ' Turn on mouse cursor (m1 = 1)
WHILE INKEY$="":WEND
CALL mouse(2, 0, 0, 0)       ' Turn off mouse cursor
END