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On Wed, 19 Mar 2008, I wrote:

> In connection with the laptop I'm planning to set up soon I've looked 
> further into pdf-viewing issues under BL3. I do need to have pdf viewing 
> capability on the laptop, so I want to be aware in advance of any problems 
> I might encounter on that front. My concerns are mainly with viewing--as 
> opposed to printing--pdf's since I seem to be able to print them just fine 
> using Sindi's gs package.

I tried my hand at compiling the latest xpdf in order to get a more 
up-to-date pdf viewer than the one recommended for BL 3.5 (the one from 
Slack4, which is version 0.7a) but it was getting a bit too involved. I 
also tried out Sindi's convert-to-ppm method, but without much success: it 
inflates the size of the pdf's tremendously (as she warned) and BL3's 
built-in graphics viewer apparently does not handle ppm anyway. At least 
it wouldn't view the ppm's I created. So I decided to just do some testing 
with the xpdf viewer recommended for BL 3.5 to see just what it would be 
capable of.

It turns out that viewer, i.e., xpdf version 0.7a, officially supports 
only up to version 1.2 of the pdf spec. I decided to throw some pdf's 
created according to later pdf specs (1.3 and >) at it to see just what 
would happen. Following are the results.

xpdf v. 0.7a seemed to render just fine all the 1.3 and 1.4 pdf's I tried 
it with. I was more interested to see how it would handle yet later pdf 
versions--documents created according to the 1.5 and 1.6 pdf spec (the 
latest version of the spec according to Wikipedia is 1.7, btw). Well, 
first of all, it was hard to find such documents: most of the pdf's I ran 
across in my searches were version 1.3 or 1.4. But I did manage to finally 
find some version 1.5 and 1.6 pdf's. Here's the report on attempting to 
view those with xpdf v. 0.7a.

When I tried to open 1.5 and > pdf files xpdf complained that they were 
later versions than it was designed to handle, but the program proceeded 
anyway. xpdf v. 0.7a was able to render all documents I tried it on (4 - 8 
documents found in web searches). There were some minor display issues 
that seemed limited to graphics (a graphic missing or skewed colors in a 
graphic), but the text portions of those documents seemed to render just 
fine.

The only trouble xpdf v. 0.7a seemed to have with any pdf document I 
looked at was in the case of encrypted pdf documents. In cases where I 
tried to open an encrypted pdf, xpdf v 0.7a would simply abort. The 
terminal output afterward indicated that this was because the document was 
encrypted. The inability of xpdf v. 0.7a to display encrypted pdf's seemed 
unaffected by the pdf spec according to which the document was created: 
perhaps it simply can't handle encrypted pdf's of any spec.

The final verdict? xpdf v 0.7a will work fine for my purposes. It will 
attempt to render post-pdf-1.2 documents and appears to do pretty well 
with rendering them, all the way up to version 1.6. Perhaps seems that the 
later pdf specs address mainly document characteristics other than simple 
text rendering: those characteristics are generally ones I am least 
interested in seeing anyway. I'm going to stick with xpdf v. 0.7a from 
Slack4 on my laptop (along with its elflibs dependency).

Case closed.

James

PS Viewing encrypted pdf's is a separate problem from viewing unencrypted 
pdf's. There exist methods for "cracking" such pdf's and, if need arises 
for reading such files under BL3, such methods may be adapted for at some 
point in the future.