1. SCREEN
Hi all,
Sorry for the precedent post it was a bit upseted.
I have a try at emulating the Qbasic _function_ SCREEN()
This function determines what character, if any, is at any given
screen location and also determines the character's color
attributes.
SCREEN(row, column [,optionflag])
where row is the screen row from 1-25, column position 1-80, and
optionflag is a numeric expression specifying which information
to return. When you omit optionflag, the function returns the
ASCII value corresponding to the character at the specified screen
position. If no character found, returns 32 (blank space). If
optionflag is present and evaluate a non zero value, SCREEN returns
the attribute (color) of the referenced character (integer
from 0-255). To decipher this information :
foreground color= attribute MOD 16
background color= (attribute AND &H70) \16
--
I used the bios service 10,8 to do that. but it don't work.
Here is the try : because a to long text it's attached file.
The call of bios seems to clear the screen and nothing is found.
am I missed something ? Any help should be hearty appreciated.
Regards,
-- Jean.Hendrickx. j.hendrickx at infoboard.be
-- SCREEN.EX simulation fonction SCREEN from Qbasic JCH 17/8/97
include machine.e
include graphics.e
include get.e
constant SCREEN=1
integer row, col, dum
atom key
sequence coord
object atrib
coord={} atrib={} key=-1
--
function Screen(integer row, integer col)
sequence inReg, outReg
inReg= repeat(0,10)
-- cursor at desired location (bios service 10,2)
inReg[REG_AX]=#0002 -- service 2
inReg[REG_DX]=row*#100 + col
inReg[REG_BX]=#0000 -- video page -------------|
outReg=dos_interrupt(#10,inReg)-- outReg={0,0,0,0,773,0,48,12870,0,0,0}
-- |
-- R=773:256=3 C=remaind=5
-- get ASCII character code in AL and attribute byte in AH
-- bios service 10,8
inReg[REG_AX]=#0008 -- service 8
inReg[REG_BX]=#0000 -- video page
outReg=dos_interrupt(#10,inReg)
return outReg --[REG_AX]
end function
--
row=1 col=1
-- coord= Screen(row,col) -- Control of service 10/2
--nrow= floor(coord[5]/256)
--ncol= remainder(coord[5],256)
--? nrow
--? ncol -- OK
position(row, col) text_color(7) bk_color(1)
puts(SCREEN,"AAAAAAAAAAA")
while key=-1 do key=get_key() end while
atrib=Screen(row,col) -- return : {0,0,0,0,257,0,32,12870,0,0}
dum=graphics_mode(-1) -- |
? atrib -- " "
-- END CODE ----
2. Re: SCREEN
- Posted by Ralf Nieuwenhuijsen <nieuwen at XS4ALL.NL>
Aug 20, 1997
-
Last edited Aug 21, 1997
Why don't you just read the video memory... it's either at at #B0000
or at #B800...
Use the library function video_config to determine the current video
mode (text or graphic) in qbasic it will equal the euphoria funtion
get_pixel in graphics mode. Also you will then know its color mode
(b&w or color) color modes are at #B800 and have two bytes (one with
the color and one with character there). The black & white modes use
#B0000 and only have one byte for each character. PS Hercules
graphics mode isn't black & white, it's internally CGA (however this
is not to the subject, it might avoid confusion)
Ralf
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
~~~~>> Ralf Nieuwenhuijsen <<~~~~
~~~>> nieuwen at xs4all.nl <<~~~~
3. Re: SCREEN
- Posted by Jacques Deschenes <desja at GLOBETROTTER.QC.CA>
Aug 20, 1997
-
Last edited Aug 21, 1997
At 18:40 20-08-97 +0100, you wrote:
>---------------------- Information from the mail header -----------------------
>Sender: Euphoria Programming for MS-DOS <EUPHORIA at
>MIAMIU.ACS.MUOHIO.EDU>
>Poster: Jean Hendrickx <jean.hendrickx at EURONET.BE>
>Organization: Infoboard Belgium
>Subject: SCREEN
>-------------------------------------------------------------------------------
>
>Hi all,
>Sorry for the precedent post it was a bit upseted.
>I have a try at emulating the Qbasic _function_ SCREEN()
>This function determines what character, if any, is at any given
>screen location and also determines the character's color
>attributes.
> SCREEN(row, column [,optionflag])
>where row is the screen row from 1-25, column position 1-80, and
>optionflag is a numeric expression specifying which information
>to return. When you omit optionflag, the function returns the
>ASCII value corresponding to the character at the specified screen
>position. If no character found, returns 32 (blank space). If
>optionflag is present and evaluate a non zero value, SCREEN returns
>the attribute (color) of the referenced character (integer
>from 0-255). To decipher this information :
>foreground color= attribute MOD 16
>background color= (attribute AND &H70) \16
>--
>I used the bios service 10,8 to do that. but it don't work.
>Here is the try : because a to long text it's attached file.
> The call of bios seems to clear the screen and nothing is found.
>am I missed something ? Any help should be hearty appreciated.
>Regards,
>-- Jean.Hendrickx. j.hendrickx at infoboard.be
>-- SCREEN.EX simulation fonction SCREEN from Qbasic JCH 17/8/97
>include machine.e
>include graphics.e
>include get.e
>constant SCREEN=1
>integer row, col, dum
>atom key
>sequence coord
>object atrib
>coord={} atrib={} key=-1
>--
>function Screen(integer row, integer col)
>sequence inReg, outReg
>inReg= repeat(0,10)
>-- cursor at desired location (bios service 10,2)
>inReg[REG_AX]=#0002 -- service 2
>inReg[REG_DX]=row*#100 + col
>inReg[REG_BX]=#0000 -- video page -------------|
>outReg=dos_interrupt(#10,inReg)-- outReg={0,0,0,0,773,0,48,12870,0,0,0}
> -- |
> -- R=773:256=3 C=remaind=5
>
>-- get ASCII character code in AL and attribute byte in AH
>-- bios service 10,8
>inReg[REG_AX]=#0008 -- service 8
>inReg[REG_BX]=#0000 -- video page
>outReg=dos_interrupt(#10,inReg)
> return outReg --[REG_AX]
>end function
>--
>row=1 col=1
>-- coord= Screen(row,col) -- Control of service 10/2
>--nrow= floor(coord[5]/256)
>--ncol= remainder(coord[5],256)
>--? nrow
>--? ncol -- OK
>position(row, col) text_color(7) bk_color(1)
>puts(SCREEN,"AAAAAAAAAAA")
>while key=-1 do key=get_key() end while
>atrib=Screen(row,col) -- return : {0,0,0,0,257,0,32,12870,0,0}
>dum=graphics_mode(-1) -- |
>? atrib -- " "
>-- END CODE ----
>
Hi Jean,
the problem is that you're placing function code in AL instead of AH
It should be:
r[REG_AX] = #0200 -- function 2 AH = 2
r[REG_AX] = #0800 -- function 8 AH = 8
try this code
------ cut here -----------
include machine.e
include image.e
function screen(integer row, integer col, integer OptionFlag)
sequence r, pos
pos = get_position()
position(row,col)
r = repeat(0,10)
r[REG_AX] = 8*#100 -- AH = 8 get character and attribute at cursor pos.
r = dos_interrupt(#10,r)
position(pos[1],pos[2])
if OptionFlag then
return remainder(r[REG_AX],256) -- return AL = character
else
return floor(r[REG_AX]/256) -- return AH = attribute
end if
end function
constant CHARACTER = 1, ATTRIBUTE = 0
text_color(BLUE)
bk_color(YELLOW)
puts(1,"Hello world\n")
? screen(1,1,CHARACTER)
? screen(1,1,ATTRIBUTE)
--- code end -------------
Jacques Deschenes
Baie-Comeau, Quebec
Canada
desja at globetrotter.qc.ca
4. Re: SCREEN
I read the listserver everyday and have been noticing a lot of talk about
QBASIC'S
screen function. I'm a commercial programer using QBASIC and a few other
languages and am now converted to EUPHORIA.
The way I got around the SCREEN() function was thus
screen_char is a single sequence containing the ASCI value in 1 and the
ATTRIB
in 2
Thus:
if screen_char[1][1]='A' then
do something
end if
Nothing much but I thought I"d comment.
ROD DAMON
5. SCREEN
The 23 Aug 97 Jacques Deschenes wrote:
.
> Hi Jean,
> the problem is that you're placing function code in AL instead of AH
> It should be:
> r[REG_AX] = #0200 -- function 2 AH = 2
> r[REG_AX] = #0800 -- function 8 AH = 8
> try this code
--Snipped----
Hi Jacques,
Thank's for your correcting of my code and for the improvement.
Now i'll know where stands AL and AH in REG'S.
-- Jean.Hendrickx. j.hendrickx at euronet.be
6. SCREEN
Hi All,
Thanks for the help. I conclude that they are several ways
to get a character and his attribute on a defined place of the screen.
To sum up :
--
1x using peek in the video memory e.g.
pos=(((row-1)*80)+col-1)*2
s=peek({#B8000+pos,2}) Cfr Reference Manual
-----------
2x using dos_interrupt rom bios service 08H
See function screen from Jacques Deschenes (23 Aug 1997)
-----------
3x using save_text_image (Cfr Reference Manual)
puts(1,"ASCII character: "& screen_char[1][1]&"\n")
printf(1,"ATTRIBUTE: %d", screen_char[1][2]&"\n")
-----------
Which one to prefer ? A matter of taste ?
Regards,
-- Jean Hendrickx. j.hendrickx at euronet.be
7. Re: SCREEN
> 1x using peek in the video memory e.g.
> pos=(((row-1)*80)+col-1)*2
> s=peek({#B8000+pos,2}) Cfr Reference Manual
-
> 2x using dos_interrupt rom bios service 08H
> See function screen from Jacques Deschenes (23 Aug 1997)
> 3x using save_text_image (Cfr Reference Manual)
> screen_char=save_text_image({row,column},{row,column})
> Which one to prefer ? A matter of taste ?
Certainly not!
text_image is the most save method (i believe) and peek it from the
memory is the fastest method
There is reason for using interrupts...
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
~~~~>> Ralf Nieuwenhuijsen <<~~~~
~~~>> nieuwen at xs4all.nl <<~~~~
