Reading screen info from memory address. 
Author Message
 Reading screen info from memory address.

I have a very specific question/problem.  I am writing a
program that creates a graphic image
that takes up all of the VGA 640 X 480 video mode.  I then
print it from the screen using GetPixel to determine if the
pixels are black or not.  (Only black pixels are to be
printed). Anyways, my problem is that I don't want to have
to read the pixels directly from the screen.
I know how to use GetImage to save the screen's information,
and also how to save that to disk.  Then, I can retrieve
that information into a variable of type

TYPE
   ImageType = RECORD
      BitMap  :  POINTER;
      Size    :  WORD;
   END;

VAR
   Image  :  ImageType;

Okay, the question is this:  Does ANYONE know how I can just
read directly from this variable like I can with GetPixel?  

JUST FOR THE INFO:  The reason I don't want to read from the
screen is that I want to be able to show a printing progress
box and some program information.  If I read directly from
the screen, then these items get printed as well.

Thank you for any advice you can give.

Hugh

P.S.  I understand VERY little about Turbo Vision.



Wed, 18 Jun 1902 08:00:00 GMT  
 Reading screen info from memory address.


Wed, 18 Jun 1902 08:00:00 GMT  
 Reading screen info from memory address.
I'm a beginner to the world of protected mode.  Does anyone have an
address for a good FAQ about this (PM as related to BP would be nice, but
not necissary).  You can recommend books too if you want, but I'm a bit
short on money right now, which is why I'm asking for a FAQ.  I basically
need to know about all the terminology involved, as well as DPMI.  Any
help would be greatly appreciated.  Thanks.

-Sam



Wed, 18 Jun 1902 08:00:00 GMT  
 Reading screen info from memory address.


Wed, 18 Jun 1902 08:00:00 GMT  
 Reading screen info from memory address.

Quote:

>Subject: Reading screen info from memory address.
>Date: 19 Jun 1995 23:32:33 GMT
>I have a very specific question/problem.  I am writing a
>program that creates a graphic image
>that takes up all of the VGA 640 X 480 video mode.  I then
>print it from the screen using GetPixel to determine if the
>pixels are black or not.  (Only black pixels are to be
>printed). Anyways, my problem is that I don't want to have
>to read the pixels directly from the screen.
>I know how to use GetImage to save the screen's information,
>and also how to save that to disk.  Then, I can retrieve
>that information into a variable of type
>TYPE
>   ImageType = RECORD
>      BitMap  :  POINTER;
>      Size    :  WORD;
>   END;
>VAR
>   Image  :  ImageType;
>Okay, the question is this:  Does ANYONE know how I can just
>read directly from this variable like I can with GetPixel?  
>JUST FOR THE INFO:  The reason I don't want to read from the
>screen is that I want to be able to show a printing progress
>box and some program information.  If I read directly from
>the screen, then these items get printed as well.
>Thank you for any advice you can give.
>Hugh
>P.S.  I understand VERY little about Turbo Vision.

I don't believe GetImage will work... Remember that it is limited to image
data < 64K... Obviously, you want to work with much larger images...

You might want to read from the screen for all but the area used for your
message. If you use Putimage for that region, you can retrieve the pixel info
from the Putimage region only and the rest from the screen...

Does this make sense???

Claude.



Wed, 18 Jun 1902 08:00:00 GMT  
 
 [ 5 post ] 

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