[comp.sys.amiga] Chopping FORMs from anims

a976@mindlink.UUCP (Ron Tarrant) (08/12/90)

> stoller@cbmcel.UUCP writes:
> 
> Msg-ID: <164@cbmcel.UUCP>
> Posted: 8 Aug 90 08:07:47 GMT
> 
> Org.  : COMMODORE ELECTRONICS LIMITED
> Person: Martin S. Stoller
> 
> So you need to chop the last two FORMs off.  Just take a good editor, load
> the
> anim into MEM (you need quite a bit of mem to do that, but read to end
> anyway),
> search for the second last FORM, then cut everything below and including
> that FORM.  (My friend has 5MEG, and my anims are never that long, so
> 
> NOTE!!!!  A DPIII ANIM with less FORMs then originally saved will NOT load
> in DPIII, 'cause the size is incorrect.  Check comp.binaries.amiga for my
> 
>    Regards,     Martin S. Stoller
> 
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I just wanted to jump in here because I spent nearly 500 hours studying the
details of all flavors of ANIM-5 files earlier this year.
First, if you want to hand chop an anim file one more simple step will
set everything right again and it will pass all inspections by whatever program
you want to load it into. Find the 5th to 8th bytes (or if you're counting from
zero, the 4th to 7th bytes) in the file. These will be a hexidecimal value
giving the size of the file. All you have to do is use a filezap utility (or a
heavy duty text editor like CygnusEd Pro) and change this hex number to reflect
the size change of the file caused by chopping off the FORMs. To find out what
number should go in here, use the list command to find the size of the file,
then subtract 8 and convert to hex.

Something I've noticed about DP-III that still has me scratching my head is
that under certain circumstances (although all my attempts to reconstruct them
have failed) DP3 will save hundreds of thousands of extra bytes of information
with an anim file. I don't remember right now what the chunk names were but
these extra bytes are not accounted for in the hex byte count at the beginning
of the file. I though it might be some kind of "save your position" type stuff
with stencil information or something like that, but this doesn't seem to be
the case.
I think it would be great if all manuals for all programs and applications
included technical details that covered such things as these. Photon Paint 2's
manual has a nice little tech section at the back and it saved me hours of
trial-and-error research time. Of course, the rest of the manual reads like a
"Dick and Jane Go to the Playground", but that's another story...
-Ron Tarrant
a976@Mindlink.UUCP