Re: [ft-devel] Rendering issues with xpdf (and other Linux based pdf viewers)

[Derek B. Noonburg]

Hi Hin-Tak,

(I'm replying from a different address because that's where I'm
subscribed to freetype-devel.)

> I have two rendering issues with xpdf, and the 2nd of which also
> affects every other viewers on Linux I have - mupdf, acroread 9.x ,
> evince. But the file works correctly on acrobat reader on android, so
> it seems to be a rendering problem, and perhaps generic to
> Linux-based viewers - for the 2nd issue. The file is
> http://htl10.users.sourceforge.net/FontVal-TypoLabs2018.pdf . Sorry
> it is a 17MB file - processing the eps alone does not trigger the
> problems.

> Page 73 - the Devanagari accents, the dotted circles shows only 3
> dots (should be about 8). Page 72 has a figure from png screen
> capture showing what it should look like.

> Page 76 - the Arabic glyphs are not positioned correctly and so the
> writing is a bit broken up.  Again page 75 has figures show what it
> should look like.

I wasn't able to reproduce this problem (or at least I don't think so
-- I don't read Devenagari or Arabic, but the results from xpdf look
similar to the screen captures you mentioned).

I'm attaching the output from pdftopng for those two pages.  Can you
send me the output you're getting?

> This problem affects every viewer I find on Linux also - mupdf,
> evince, acroread 9.x.

Is there any chance that you have some configuration (environment
vars?) that affects FreeType, on your system?  You mentioned that you
tried the binaries from my web site, which are staticly linked to
FreeType, so that should rule out anything but configuration.

The pre-built xpdf 4.00 binaries are linked to FreeType 2.8.  I also
tested my current development code, using FT 2.9.1 -- same results.

> I also have a small complaint about the new 4.0 GUI - the navigation
> forward/backward buttons don't do next/previous page, but does some
> kind of history navigation - e.g. If you do page 1, then jump to
> page 50 with the explicit page number input, then press the backward
> button, it goes back to page 1 rather than page 49. Also "n" and "p"
> don't work like the 3.0 motif/lesstif GUI... So navigation is a bit
> painful with the 4.0 GUI.

I chose to remove the next-page and previous-page buttons from the
toolbar, because I think that most people use keystrokes for those,
and I wanted to maximize the window space devoted to displaying the
PDF file.  By default, PageDown and space are bound to next-page, and
PageUp is bound to previous page.  You can add bindings for 'n' and
'p' in ~/.xpdfrc:

bind n any nextPage
bind p any prevPage

- Derek

page73.png
Description: PNG image

page76.png
Description: PNG image