Running inkscape without X server

Question

I am running inkscape from a Gearman PHP process on *nix-like systems (OS X 10.6.8, Linux of varying flavours) to convert SVG images to either PNG or PDF. I use something like this (line breaks added here just for clarity):

/full/path/to/inkscape -z \
    --export-png=/path/to/output.png \
    --export-width=100 --export-height=100 \
    /path/to/input.svg

It works, but despite the -z flag ("Do not use X server") I get this in my console output (on OS X):

Setting Language: .UTF-8

(process:44699): Gtk-WARNING **: Locale not supported by C library.
    Using the fallback 'C' locale.
Xlib:  extension "RANDR" missing on display "/tmp/launch-WvcqRh/org.x:0".

This suggests to me that inkscape is loading more libraries than it needs to, and that it could be faster if it didn't try to connect to an X server. However, other than using the -z/--without-gui flag, I am not sure what to try. Performance on my dev machine is still sub-second (at least for trivial SVG files), but I'd like to clean this up if I can. Even if the best answer is just "suppress error output"!

Maybe if I turn off or reset a bash DISPLAY env var? I'm not at all familiar with X.

Answer 1

Yes, if you want to make your programs not find X at all, you can unset DISPLAY before launching the process.

You can also use Xvfb to "fake" an X server: http://en.wikipedia.org/wiki/Xvfb

You might also want to look at these tools:

• http://cgit.freedesktop.org/~cworth/svg2pdf/
• http://cgit.freedesktop.org/~cworth/svg2png/

Their source code is really small.

Answer 2

Another way to suppress the output, while preserving the ability to respond to true errors, is to call Inkscape from Python.

import subprocess               # May want to use subprocess32 instead

cmd_list = [ '/full/path/to/inkscape', '-z', 
             '--export-png', '/path/to/output.png',
             '--export-width', 100,
             '--export-height', 100,
             '/path/to/input.svg' ]

# Invoke the command.  Divert output that normally goes to stdout or stderr.
p = subprocess.Popen( cmd_list, stdout=subprocess.PIPE, stderr=subprocess.PIPE )

# Below, < out > and < err > are strings or < None >, derived from stdout and stderr.
out, err = p.communicate()      # Waits for process to terminate

# Maybe do something with stdout output that is in < out >
# Maybe do something with stderr output that is in < err >

if p.returncode:
    raise Exception( 'Inkscape error: ' + (err or '?')  )

On my Mac OS system, the crufty status messages (described by the original poster) end up in err. Plus, for a particular job that I ran, there is additional messaging that ends up in out:

Background RRGGBBAA: ffffff00
Area 0:0:339:339 exported to 100 x 100 pixels (72.4584 dpi)
Bitmap saved as: /path/to/output.png

(The input svg file had a size of 339 by 339 pixels.)