bug#7556: 24.0.50; visiting an EPS file with preview TIFF image and with one long line

[Eli Zaretskii]

> From: Peter Dyballa <Peter_Dyballa@Freenet.DE>
> Date: Sat, 4 Dec 2010 22:59:29 +0100
> Cc: 
> 
> I have an EPS file created by Adobe Illustrator 15 with a "DOS EPS  
> Binary File Header" according to 5002.EPSF_Spec and a TIFF preview at  
> the end, in mac-roman-mac encoding. Size: 643 KB. When I visit that  
> file from a dired buffer in PostScript DocView View mode

Visiting binary files with anything but find-file-literally is not a
good idea.

> Rendering this in a window of 55 lines and around 120 columns takes  
> these 7 h.

Emacs display engine is known to be very slow with very long lines.
Does it help to set truncate-lines non-nil?

> And more: GNU Emacs creates a #file.eps# backup file,  
> larger in size (50 %) than the original file. Is that the expected  
> behaviour?

I'm guessing that this is because raw bytes are decoded into internal
format that makes them take 5 bytes.  The auto-save file is written in
this internal format.