🚀 go-pugleaf

In article <123@snll-arpagw.UUCP> paolucci@snll-arpagw.UUCP (Sam Paolucci) writes:

>It is my understanding that optional means that a file that does not make
>use of any Amiga specific ViewModes does not need to contain it, but if
>it does, then it should.  You cannot assume that anything larger that
>640x400 is HIRES and LACE, since when higher resolutions will start
>appearing on the Amiga, this procedure will fail.  I just don't like
>the idea of decisions based on hardwired current numbers.

What I meant was that the CAMG chunk is "nonstandard" -- defined AFTER
the FORM, thus optional *by definition*.  The fact is, any viewer
program *must* understand the hardware to use it...  new hardware will
obsolete the old software, whether by making the IFF-writing files
obsolete by not taking it into account, or the viewers for he same.
If a viewer program knows about a new 1024x800 screen mode available,
it can deduce that from the image size, without the CAMG chunk.  A
viewer which does NOT know how to deal with the new screen mode will
ignore it even if it is specified in a CAMG chunk.  No matter what you
do, you're still stuck with the position of hardwiring current
hardware capabilities, at least to some extent.  Inclusion (or not) of
a CAMG chunk does not affect that.

>There are reasons to use interlace even when noninterlace is available,
>particularly if you are trying to use the video capability of the Amiga.

Then include the CAMG chunk to specify that, if interlace is
specifically desired.

>I maintain that they are poorly written since there is more than one
>way to interpret the file just by looking at the size of the picture
>and number of bitplanes.

So?  Let the program do its best to find the "best" interpretation of
the file, where ambiguities lie.

>There is also nothing wrong in using your own color table as opposed as
>what's contained in a file.  What you do with the picture is nobody's
>business.  All I'm asking is that complete and correct information
>should be contained in the file so that if somebody wants to use it,
>it's there.

The more complete and more correct the information, the better.  But
that still doesn't make the CAMG chunk required, even for a HIRES &
LACE screen.

>I never claimed that all programs must supply one.  All I said that only
>when Amiga specific ViewModes are used, than a CAMG chunk should be
>written in the file.  If this information is superfluous , as you seem
>to claim, than perhaps we should obsolete this chunk :^).  My claim is
>that it is not superfluous, and it will become more and more essential
>as more resolutions are available on the Amiga and as more IFF ILBM files
>are generated on other computers.

I did not claim it was superfluous.  It is often redundant.  There is
a difference.  It can contain useful *hints* but the chunk cannot be
thought of as required even when Amiga-specific viewmodes are used.
Even HAM mode.  Highly recommended, to be sure, but NOT required.

Deven
--
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