🚀 go-pugleaf

joe@proto.com (Joe Huffman) writes:

>pdh@netcom.com (Phil Howard ) writes:

>>I notice the int 33h functions mostly deal with a row and column, and I
>>assume this refers to the existing video mode.  Can the mouse drivers
>>handle all the video modes at least through to 1280x1024 in terms of
>>knowing correctly the number of columns and rows?  Or do you HAVE to use
>>functions 7 and 8 to tell the driver?

>Use subfunction 12 and draw the mouse cursor yourself.  I don't know of
>any mouse drivers that know of all the various super VGA modes.

I have done just what Joe Huffman suggests.  I have written my own graphics
library and interfaced with the mouse and drawn my own mouse pointer.
I used functions 7 and 8 to tell the mouse driver how many rows and columns
a certain SVGA mode has and used other functions to check where the mouse
pointer is located.

This ALMOST works.  The problem is that the X coordinate of the mouse pointer
is always an integral multiple of 8.  I don't know whether this is specific
to my mouse and mouse driver (I have a Gateway 486-33 with Microsoft mouse
and driver) or whether this happens with all mice.  My guess is that when
the  mouse driver detects a graphics mode change it doesn't recognize, it 
assumes the characteristics of text mode.  In text mode, all coordinates
are multiplied by eight, resulting in a 640x200 coordinate space (rather
than 80x25).

Has anyone encountered this problem before?  I have thought of a workaround
that should work.  I could use functions 7 and 8 to set the resolution to eight
times what it really is and divide by eight when I read the coordinates.
This is obviously a kludge and might fail if another mouse/driver works
differently.  I would appreciate an explanation and/or a fix for this
behavior from someone who has mastered this problem.

Thanks!

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=                  Greg Reid   (gar@catt.ncsu.edu)                  =
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