ImageMagick failure on Ubuntu 18.04

[hepdata]

ImageMagick failure on Ubuntu 18.04

[clelange]

Probably related, this is also causing issues when using SWAN (both python3 and legacy python stacks):

---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
<ipython-input-5-58ae0b37a4f9> in <module>
      3 table.add_variable(exp)
      4 submission.add_table(table)
----> 5 submission.create_files("example_output")

~/.local/lib/python3.6/site-packages/hepdata_lib/__init__.py in create_files(self, outdir)
    478         # Write all the tables
    479         for table in self.tables:
--> 480             table.write_output(outdir)
    481 
    482         # Copy additional resource files

~/.local/lib/python3.6/site-packages/hepdata_lib/__init__.py in write_output(self, outdir)
    229         :type outdir: string
    230         """
--> 231         self.write_images(outdir)
    232         self.write_yaml(outdir)
    233 

~/.local/lib/python3.6/site-packages/hepdata_lib/__init__.py in write_images(self, outdir)
    251             command = "convert -flatten -fuzz 1% -trim +repage {} {}/{}".format(
    252                 image_file, outdir, out_image_file)
--> 253             command_ok = helpers.execute_command(command)
    254             if not command_ok:
    255                 print("ImageMagick does not seem to be installed \

~/.local/lib/python3.6/site-packages/hepdata_lib/helpers.py in execute_command(command)
     35         for line in proc.stderr:
     36             result = result + line
---> 37         raise RuntimeError(result)
     38     return True
     39 

RuntimeError: convert: UnableToOpenConfigureFile `magic.xml' @ warning/configure.c/GetConfigureOptions/714.
convert: UnableToOpenConfigureFile `delegates.xml' @ warning/configure.c/GetConfigureOptions/714.
convert: FailedToExecuteCommand `'gs' -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 '-sDEVICE=pngalpha' -dTextAlphaBits=4 -dGraphicsAlphaBits=4 '-r72x72'  '-sOutputFile=/tmp/magick-400EDeqaEdlyWFq%d' '-f/tmp/magick-400p772kieSgsyo' '-f/tmp/magick-400wdnbYQGQ4Erm'' (1) @ error/pdf.c/InvokePDFDelegate/291.
convert: NoImagesDefined `example_output/Figure_006-a.png' @ error/convert.c/ConvertImageCommand/3275.

[AndreasAlbert]

I tried running the image conversion also in our tests in #73, but the conversion fails like this:

E           RuntimeError: convert.im6: Postscript delegate failed `/home/travis/build/HEPData/hepdata_lib/examples/example_inputs/signalEffVsMass.pdf': No such file or directory @ error/pdf.c/ReadPDFImage/677.
E           convert.im6: no images defined `test_output/signalEffVsMass.png' @ error/convert.c/ConvertImageCommand/3044.
hepdata_lib/helpers.py:37: RuntimeError

While that error looks like there is a missing file, I do not think that that is possible, since our code explicitly checks the existence of the file before running the command.

See build log

[AndreasAlbert]

(It does succeed starting from a PNG, though. Only PDF inputs fail.)