Hi.

On Tue, Sep 25, 2007 at 08:38:37AM -0400, Robert Carlson wrote:
> 1. Started with a 152.3 K linearized map.
> 2. Changed it to non-linearized, which reduced its size to 151.7 K.
> 3. Added a small rectangle, increasing the size to 549.7 K.
> 4. Added two short words in 18 point type, increasing the size to 948.4 K.
> 5. Added two short lines linking word to rectangle, increasing size to
> 1.7 MB.
> 
> I assume the original map to be vector graphics.  Is that extent of file
> size change to be expected for such a minor edit of a file of that kind?

Yes, this is known issue. PDF format is based on objects which
represent all entities of document. Everything displayed on a page is 
stored in a content stream (special type of stream object) in form of 
serialized operators (pretty much data). PDF format enables compression 
of this data to reduce file size. (see
http://partners.adobe.com/asn/tech/pdf/specifications.jsp Chapter 3 for 
more information).
However we haven't implemented compression yet. Whenever something is
changed in document, all changed objects are appended to the original
content with some maintenance information.
This means that each changed page (everything visible) has its whole 
content stream uncompressed. Therefore, when you make 3 changes on one
page in 3 separate revisions, there will be 3 copies of uncompressed
content stream (with relatively small changes).

I hope that support for compression comes in some future.

> 
> Running PDFEdit version 0.3.2 under openSUSE 10.2 x86_64.
> 
> Bob Carlson
> Alexandria, Virginia, USA

Sorry for such technical information, but maybe someone can help us
with this issue. 

Best regards
-- 
Michal Hocko


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