Problem with DOS PB in Windows 98

[Pat Bruening]

I have written two procedures in PB3.2 to read the screen so as
to save its contents, to be later shown again. In other words,
by saving part of the screen, I can restore that part if over-
written. Here is the code, which does not work in WINDOWS 98,
nor in WINDOWS 95 if the procedure is called by another procedure
in a different module.

FUNCTION PARTIAL.LINE.CAPTURE$(byval R,byval C, byval W) PUBLIC
IF W=0 THEN W=PbvScrnCols+1-C
x$=space$(2*W):count=1
for J=C to W-1+C
    if J<81 then
       Mid$(x$,count,1)=chr$(screen(r,j))
       incr count
       Mid$(x$,count,1)=chr$(screen,r,j,1))
       incr count
     end if
Partial.line.capture$=x$
end function
 
'---------------------------------------------
 
FUNCTION PARTIAL.LINE.CHAR$(byval R,byval C,byval W) PUBLIC
   IF W=0 THEN W=PbvScrnCols+1-c
   x$=partial.line.capture$(r,c,w)
   y$=spaces(w):j=1
   for k=1 to 2*w step 2
       mid$(y$,j,1)=mid$(x$,k,1)
       incr j
   next k
   partial.line.char$=y$
end function

thanks for the help.
Pat


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[Lance Edmonds]

Are you sure the code is actually being executed? Can you step through it with the debugger.

It seems possible that the code is somehow not be $INCLUDEd or $LINKed and that your code is using a pair of local string variables instead. Using $DIM ALL will help, but may not be practical if your code is very large.

Basically, there is nothing in those functions that should be affected by Windows.

If memory is not a problem, maybe try using these routines that save a snapshot & restore a snapshot of the entire screen (assuming 80x25).

' Save screen as snapshot into String Variable
SUB SaveScreen(a$) LOCAL public
    def seg = pbvScrnBuff \ 65536
    a$ = PEEK$(0,4000)
    def seg
END SUB
 
' Restore screen from snapshot held in String Variable
SUB RestoreScreen(BYVAL a$) LOCAL public
    def seg = pbvScrnBuff \ 65536
    POKE$ 0, a$
    def seg
END SUB

These require approx 4K per snapshot, but are very fast.

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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Pat Bruening]

Lance,
Thanks for your quick reply. Saving the whole screen, in my
application, won't work, because I want to save several lines
after modifying parts of the screen. When I recalled the original
screen, it would then overwrite the screen changes made after
saving the screen.
Yes, I did step thru it. Other code in the same module works. It
seems that the "SCREEN" function doesn't work in Windows 98 and
when this function is called by a different module, both of which
are linked to the MAIN module.
The function had been placed in a ".PBU" and works in DOS with
WINDOWS 95. In fact, any changes I make to a program in Windows
98, using PowerBASIC, never seem to change. However, if I compile
these changes on the DOS (Windows 95) machine, I can then simply
copy them to the Windows 98 machine, and except for this function,
the programs work.
It seems that Windows 98 doesn't have a "REAL" DOS; that is, a
DOS that functions like the normal DOS should. Any hints or
have you received other such errors from other users?
Thanks in advance.
Pat

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[Jerry Fielden]

Peek$ and Poke$ is still your best choice.

You don't have to copy and paste back the whole screen with
Lances little Subroutines. Just change your starting address
and the number of bytes to copy only the rows you want.

SUB SaveScreen(a$) LOCAL public
    def seg = pbvScrnBuff    
    a$ = PEEK$(0,320) ' will copy the first two rows since theres   
    def seg           ' 160 bytes in each row
END SUB 


SUB RestoreScreen(BYVAL a$) LOCAL public    
    def seg = pbvScrnBuff    
    POKE$ 0, a$    'Pokes$ starting address will stay the same
    def seg
END SUB


If you really want to zero in on an area of the screen and not copy
full rows, you can use routines similar to the following. They 
not only let you copy an area but they let you put it back in a 
different location. They were written in PB3.0, I think they will
still work with 3.2. 


SUB textgetz (r1%, c1%, r2%, c2%, sa$()) 
     'MouseHideCursor        'Mouse cursor will discolor screen
     DEF SEG = &HB800        'Address of a color screen
     ERASE sa$               'erase last copy
     DECR r1%
     colx% = (c2% - c1%) * 2                'get number of bytes
     col1% = (c1% * 2) + (r1% * 160) - 2    'Get start address
     ro% = r2% - r1%                        'get rows to copy
     FOR x = 1 TO ro%
	sa$(x) = peek$(col1%, colx%)  'Load each row portion in array
	INCR col1%, 160               'Starting address for next row
     NEXT x
     'MouseShowCursor                  'turn mouse back on
END SUB


SUB textputz (r1%, c1%, r2%, c2%, sa$()) 
     'MouseHideCursor
     DEF SEG = &HB800
     DECR r1%: DECR c1%
     col1% = (c1% * 2) + (r1% * 160)
     ro% = r2% - r1%
     FOR x = 1 TO ro% + 1
       POKE$  col1%, sa$(x)
       INCR col1%, 160
     NEXT x
     'MouseShowCursor
END SUB

r1% is the top row of the rectangle
r2% is the bottom row
c1% is the starting column
c2% is the ending column

If you want to copy an area starting at row 3 and column 10 and
end at row 15 and column 20, you would call

TextGetz 3, 10, 15, 20, sa$()

to put it back

TextPutz 3, 10, 15, 20, sa$()

Anyway, it works for me and works in every windows I ever tried.
I'm pretty sure I've used the DOS Screen Function in windows
before and it worked.

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[This message has been edited by Jerry Fielden (edited May 16, 2001).]

[Gary Akins]

Pat - for whatever it's worth, your routine (and the SCREEN(r,c,a) statement) does work in a DOS box on my Win98 system, both maximized and as a window. Nor do I have any problems such as you describe, compiling PB/DOS stuff on Win98 machines...

Can you be a little more specific about what you mean by "not working"? Do your functions fail to execute at all, execute but return a null string, or execute and return something other than what you expected to get back?

Ah - just noticed something on re-reading the thread. You're using PowerBASIC 3.2, not 3.5? Lance - any known issues between 3.2 and Win98 that could explain this?


[This message has been edited by Gary Akins (edited May 17, 2001).]

[Lance Edmonds]

Nope... none that I am aware of, and certainly none with the SCREEN function.



------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Pat Bruening]

Gee Gang! Thanks.
Gary,
To be more specific, a null value is returned, as tho the
call was never made.

Jerry,
Thanks much for your alternate routine, using PEEK$ and poke$.
It certainly is more primative than SCREEN which I think uses
PEEK$ anyway. However, my basic problem remains. I cannot use
SCREEN(r,c,1) to read the screen in a DOS window under WINDOWS 98.
I'll try some other routines that use SCREEN and get back to all
of you.

Again thanks.
Pat

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[Tom Hanlin]

SCREEN almost certainly goes through BIOS calls (or possibly direct memory access,
in text mode at least). The only likely prospect for any sort of failure would be
a bad display driver. Make sure you've got the latest driver for your display adapter.
If that doesn't help, try replacing the display adapter entirely. Odds are about
infinite that you're being hosed by the video card.


------------------
Tom Hanlin
PowerBASIC Staff

[Pat Bruening]

Gang!

Again thanks.
I tried using SCREEN and PEEK$/POKE$ in a new program, dedicated
only to saving a partial line. I then placed the code in a UNIT
and then called it from another unit. In every case it worked.
Maybe I had better look at the original code that caused the
problem. It may have nothing to do with SCREEN or PEEK/POKE.
Thanks again.
Pat

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[Gary Akins]

Pat - there were a couple of typos in the code you initially posted, and a missing NEXT statement; but, since the code wouldn't compile at all in its posted form (as opposed to compiling, but "not working"), I just assumed they'd been introduced while typing your code into the forum, as opposed to being part of your original code...

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