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_Gigi_Marcu_
Participant
July 18, 2008
Question

Images in PostScript

  • July 18, 2008
  • 5 replies
  • 1650 views
Hi!

I am kind of new in PostScrip programming (actually code generation from C) and I want to know if there are some kind of encoding of an image when you need to write what it contains in the .ps files.

Can I write the bytes it contains using hexadecimal numbers or is there some kind of encoding I have to do.

Thanks in advance!
This topic has been closed for replies.

5 replies

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_Navaneeth_Sivappan_
Participant
October 29, 2008
Hi Gigi n Aandi,

If you have a jpeg image and you want to make it smaller,then you can use "SCALING"
The scale operator allows you to change the size of the units,so that the image can be compressed.

Regards,
Navaneeth Sivappan
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_David_Cristian_
Known Participant
July 22, 2008
Hi

Tell me if i got this straight ...

If i have a jpeg image and i want to make it smaller i have to take the binary file that represent the picture and apply the LZW encoding, and after that an ASCII85 conversion.

Would tis work?
I ask this because i have already implemented this and I want to see I have any logical problem.

David
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_Aandi_Inston_
Participating Frequently
July 22, 2008
>If i have a jpeg image and i want to make it smaller i have to take the binary file that represent the picture and apply the LZW encoding, and after that an ASCII85 conversion.

Well, that would produce a valid image but it would be larger than the
JPEG in most cases.

For most JPEG files you can use them directly, treating them as having
DCT encoding, then apply ASCII85.

Aandi Inston
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_Gigi_Marcu_Author
Participant
July 18, 2008
I understand.
Thanks for the tips!
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_Gigi_Marcu_Author
Participant
July 18, 2008
I have read something about LZW and ASCII 85 conversion and it seems like a little work, that i don't want to do for nothing.
Do you think the combination of filters is much better than simple hexadecimal?
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_Aandi_Inston_
Participating Frequently
July 18, 2008
The only reason to use ASCII85 rather than ASCII, and the only reason
to use LZW rather than nothing, is because it makes a smaller file.
The smaller file might get to the printer more quickly. LZW is more
work for the printer, so it potentially prints more slowly when it
arrives.

Aandi Inston
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_Aandi_Inston_
Participating Frequently
July 18, 2008
PostScript is very flexible. You can use raw data (but many printers
will choke on this), simple hexadecimal, or a combination of filters
(such as LZW encoding then ASCII 85 conversion).

Aandi Inston
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