[OSM-talk] SVG to PDF

[Andy Armstrong]

On 19 Dec 2006, at 22:52, David Earl wrote:

> PDF files are read from the *end*. At the end of a PDF file is a  
> number
> which is an offset within the file where the reader can find a  
> table (a
> "dictionary" in PDF parlance) which (possibly indirectly)  
> identifies all the
> elements (pages, graphics, ...) in the file versus the offset  
> within the
> file where these appear. (In this way, you can append a new chunk  
> onto the
> end of the file which replaces the table, thereby modifying the  
> content
> selectively without rewriting the whole file - a bit like multi- 
> session
> CDs).

Can that possibly be true? I've generated PDFs without ever having to  
consider that the decoder might be reading from the end. How does a  
PDF viewer start displaying a partially downloaded file if that's true?

-- 
Andy Armstrong, hexten.net