On Fri, 30 May 2003, Walter Ian Kaye <[log in to unmask]>
wrote:
>Well I have GC 4.6.1 on OS X... hmm, in the "GraphicConverter Suite"
>there is a command called 'change comment' but it refuses to compile
>-- in fact, I put in the raw event codes and it wouldn't decompile to
>terminology. I think there's a bug there.
Makes one leery of certain aete programmers, doesn't it? But then
one could be leery of just about every piece of software ever
written, because every single one has bugs.
>>>Seems very complex. I am a little more leery of such a direct
>>>manipulation.
>>
>>Which begs the question why apparently indirect manipulation is less
>>leer-inducing in some folk
>
>I don't think that's the leeriness inducer.
>
>>I'm making no promises that I've properly understood the JPEG file
>>structure
>
>I think that's it. ;)
Sure, I wouldn't trust myself either, even if I were me... which I'm
not. So in summary, we want a ready-made solution to this problem.
We don't want to spend any time to learn the structure of JPEG files,
in order to be confident that our method, using whichever of various
earlier-suggested tools, will work; instead we want someone else to
have already done all the hard/easy/boring work for us... and if
they've written copyrighted software, however potentially buggy, then
we'll assume they know what they're doing, even though that's just a
naive faith in their abilities on our part based upon our failure to
step back and consider the wider picture/the lesson of experience.
Is that a fair assessment of the situation, Chip? ;-) Don't take it
personally; he didn't.
Incidentally, I've since found that there is at least one other type,
or pseudo-type, of JPEG file (never before noticed by me) that begins
with 'Exif' in its data fork instead of JFIF. Using
GraphicConverter's (3.6.2) 'Change JPEG/JFIF Comment' menu does not
appear to work for this sort of file. The pop-up window shows
sufficient blank space implying the comment is there, but it is not
visible/displayed in the window, and it can't be altered/deleted
(more pro. bugginess?)... other than by opening (decompressing) the
file in GC, then using the 'Show Comments' menu (under Picture), &
then deleting/altering the displayed comment prior to re-saving the
file (i.e. lossy, like scripting GC, apparently). Unfortunately I
can't discern the pattern or structure of this type of file's data.
Part of the problem is that re-saving such a file in GC after
altering/deleting its comment produces an ordinary JFIF file (i.e. GC
3.6.2 can't save a file in the Exif format), so it's hard for me to
test/compare the data's structure. A quick look at the web suggests
Exif is a meta-data scheme used mainly by various scanners/digital
cameras, etc.
Bugs bunny
Selected from Ambrose Bierce's "Devil's Dictionary":
FIDELITY, n. -- A virtue peculiar to those who are about to be betrayed.
|
