[reportlab-users] Reducing use of 7-bit characters

Yoann Roman yroman-reportlab at altalang.com
Tue May 5 08:35:17 EDT 2009

>> This thread talks about optional tweaks to reduce RL's 7-bit use:

>> http://tinyurl.com/cwea65


> Switching between Ascii base 85 and Ascii base 64 probably wouldn't

> matter much as both are ASCII. There are other encoding options but

> also we might need to have less nice neat sub-80-character line

> endings; we could fiddle forever.

The base 85 streams aren't line wrapped in the output I'm getting. I actually
tried playing with the line wrapping, and it didn't seem to do anything.

> If we could determine exactly what causes the problem in a manner

> ReportLab could reproduce in the lab, we could fiddle with things to

> fix it. Do you know if it's just the attaching process (i.e. attach

> then detach without even sending), if it needs an exchange server,

> which Outlook versions demonstrate this etc?

It depends on what you want to reproduce. I can reliably get Outlook 2003 to
attach PDFs as quoted-printable, but I can't get the corruption to happen. The

message definitely needs to be sent to get corrupted, and it only seems to be
corrupt on the receiving end if (1) a mail server mangled the line endings
or (2) the receiving end decodes with a different line ending than the
file had. The receiving end doesn't need to be an Exchange server (we don't
use one and have a lot of problems with AOL recipients) nor does the recipient

have to use Outlook (again, AOL users).

I guess I'm just wondering how Acrobat encodes its streams differently to have

a higher non-7-bit ratio and if there's an easy way to do the same thing in


Yoann Roman

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