Re: corel files cdr and cmx and thumbnails in it

"JohnShade" <profesor_kinbote@xxxxxxxxxxxxxx> wrote in message
news:1166613148.730576.223960@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
JohnShade napisal(a):
[jongware] napisal(a):
"JohnShade" <profesor_kinbote@xxxxxxxxxxxxxx> wrote in message
news:1166460689.302076.285230@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
How to extract miniature rester images which are contained in corel
vector
graphics files (I mean .cdr and .cmx) ? I have done a very notifable
amount of
work searching up and down the internet - and I do not know still
how
can I do it.

Ppl say that .cdr is (or was) proprietary format so i am not sure if
I
have a rights
to extract this thumbnail from it, but cmx should be free and is (
ppl
say )
documented by corel - but i still cannot find this documentation. I
ve
found
2 small pices of code by ppl in theme of reading cmx but it has not
enough information
to me and I still know almost nothing except that in this files
there
are sometimes
inside raster miniarures of proper vestor graphics in it. BUt where
exactly and exactly
in which format?

Use (or write) a program to examine these files. Somewhere near the
beginning you can see the bitmap, in a 256-indexed color format and
(most
likely!) of a fixed size -- perhaps, being thumbnail sized, something
like
64x64. Examining a number of files can tell you if the position of
this
bitmap in the file is always the same (likely), or there is an offset
very
close to the start of the file which points to it. The 256 colors are
(again, most likely) taken from a fixed palette, or there are 256 RGB
color
values very close to the start of the file.
The reason everything is "close to the start of the file" is so
programs
which want to display the preview do not have to read the entire file
first.
The reason for making the layout as simple as possible (fixed position
in
the file, fixed size, and fixed color palette) is to make reading and
displaying as fast as possible.
Note that Corel may have the option of saving without thumbnail, so
you
can't always rely on this information -- but again, some flag in the
file
header should tell you.

[Jongware]

You're right! Indeed i tried it and i ve done it, There It was simple
(speakin about .cdr
because cmx are still mystery for me)- in cdr there is from offset 0x14
an regular
256 color bitmap with about 14 bytes of headrer "damaged"
(overvritten), - so read from
stream, cut and recreate this few bytes and there we have a bitmap.

JSh

sorry for my bad english

cmx is very simple too - i post it for a some man who maybe will
searching through
usenet in this theme ;) - same as cdr except there is a 24b bitmap (no
paltte)
and bitmap offset in cmx is 0x116 no 0x014 as in cdr)

Congratulations! Not only do you have a fish to eat, but you know how to
catch one as well.

[Jongware]


.

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