1. multiple video pages?
I was having difficulty and am hoping that someone can help me. What I want to
do is to load a gif image on a hidden screen and then save sections of the image
into some sequences. I thought that either changing the active page or the
display page while I did this would work I can't seem to find a graphics mode
that supports more than one video page and supports 640 by 480 resolution.
So what I want is a graphics mode that supports more than one video page, 640 by
480 pixel graphics, and preferably 256 color (although I'd settle for 16 if I
had to.) So far I've had no luck. I've tried to following modes (* indicates
that it does not seem to support more than one video page, ^ indicates that it
doesn't seem to be compatible with my system): 18*, 19*(not 640 by 480), 257*,
258^, 259^, 260^, and 261^.
Is there a mode that I overlooked? Would a mode that I mentioned above actually
work, but I just didn't realize it? Is there another way of hiding something
from the user without using a different active/display video page? I'd
appreciate any help anyone can give.
Thanks in advance,
Joshua Milligan
silverlaser at HoTMail.com
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2. Re: multiple video pages?
- Posted by Greg Harris <blackdog at MAIL.CDC.NET>
Apr 21, 1997
-
Last edited Apr 22, 1997
> So what I want is a graphics mode that supports more than one video page, 640
by
> 480 pixel graphics, and preferably 256 color (although I'd settle for 16 if I
> had to.) So far I've had no luck. I've tried to following modes (* indicates
> that it does not seem to support more than one video page, ^ indicates that it
> doesn't seem to be compatible with my system): 18*, 19*(not 640 by 480), 257*
,
> 258^, 259^, 260^, and 261^.
Your video card may support these modes but needs a special driver to
access them in DOS. For example, I have a Viper video board which by
the book says that I support these modes and more however when I run
a program that calls these mode it gets a -1. If I load a VESA driver
before running the program it works. You may need an external VESA
driver for your card to access these modes.
L8r,
Greg
3. Re: multiple video pages?
- Posted by Michael Bolin <michaeltom at GEOCITIES.COM>
Apr 21, 1997
-
Last edited Apr 22, 1997
> I was having difficulty and am hoping that someone can help me. What I want
to
> do is to load a gif image on a hidden screen and then save sections of the
image
> into some sequences. I thought that either changing the active page or the
> display page while I did this would work I can't seem to find a graphics mode
> that supports more than one video page and supports 640 by 480 resolution.
None of the DOS 256-color graphics modes have more than one page.
However, if you're going to load a GIF image, you'll already have the
image in a sequence, and if you wanted to make copies of different
sections of it, it would be easy to write a short routine that would
do this.
Regards,
Michael Bolin
4. Re: multiple video pages?
- Posted by Michael Packard <lgp at EXO.COM>
Apr 21, 1997
-
Last edited Apr 22, 1997
On Mon, 21 Apr 1997, Joshua Milligan wrote:
>I was having difficulty and am hoping that someone can help me. What I want to
>do is to load a gif image on a hidden screen and then save sections of
>the image
> into some sequences. I thought that either changing the active page or the
> display page while I did this would work I can't seem to find a graphics mode
> that supports more than one video page and supports 640 by 480 resolution.
>
> So what I want is a graphics mode that supports more than one video
>page, 640 by
> 480 pixel graphics, and preferably 256 color (although I'd settle for 16 if I
> had to.) So far I've had no luck. I've tried to following modes (* indicates
> that it does not seem to support more than one video page, ^ indicates that it
> doesn't seem to be compatible with my system): 18*, 19*(not 640 by
>480), 257*,
> 258^, 259^, 260^, and 261^.
>
> Is there a mode that I overlooked? Would a mode that I mentioned above actual
ly
> work, but I just didn't realize it? Is there another way of hiding something
> from the user without using a different active/display video page? I'd
> appreciate any help anyone can give.
when you load the image, it is stored as a sequence. Just index into that
sequence y,x and grab the section you want.
something like:
image=read_gif("botswana.gif")
temp=image[2] -- this is the data of the image
if you want the 50x80 section of the image starting at pixel location
{10,30} you would
section=repeat(0,80) --dimention the sequence for 80 lines high
for i = 1 to 80 do
section=temp[i+29][10..59] -- grab the 50 pixels from 10 to 59 starting
at y=30.
end for
do this for whatever section you need.
Michael Packard
Lord Generic Productions
lgp at exo.com http://exo.com/~lgp
A Crash Course in Game Design and Production
http://exo.com/~lgp/euphoria
5. Re: multiple video pages?
I wrote:
>>I was having difficulty and am hoping that someone can help me. >>What I want
to do is to load a gif image on a hidden screen and then >>save sections of the
image into some sequences. I thought that >>either changing the active page or
the display page while I did this >>would work I can't seem to find a graphics
mode that supports more >>than one video page and supports 640 by 480
resolution.
Michael Packard wrote back:
>when you load the image, it is stored as a sequence. Just index into >that
>sequence y,x and grab the section you want.
>
>something like:
> <example code was here>
I'd actually thought of doing something like that. Thanks for your help.
Joshua Milligan
silverlaser at HoTMail.com
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