CGSpace Notes

2017-03-01

• Run the 279 CIAT author corrections on CGSpace

2017-03-02

• Filed an issue on DSpace issue tracker for the filter-media bug that causes it to process JPGs even when limiting to the PDF thumbnail plugin: DS-3516
• Discovered that the ImageMagic filter-media plugin creates JPG thumbnails with the CMYK colorspace when the source PDF is using CMYK
• Interestingly, it seems DSpace 4.x’s thumbnails were sRGB, but forcing regeneration using DSpace 5.x’s ImageMagick plugin creates CMYK JPGs if the source PDF was CMYK (see ¹⁰⁵⁶⁸⁄₅₁₉₉₉):

$ identify ~/Desktop/alc_contrastes_desafios.jpg
/Users/aorth/Desktop/alc_contrastes_desafios.jpg JPEG 464x600 464x600+0+0 8-bit CMYK 168KB 0.000u 0:00.000

• This results in discolored thumbnails when compared to the original PDF, for example sRGB and CMYK:

• I filed an issue for the color space thing: DS-3517

2017-03-03

• I created a patch for DS-3517 and made a pull request against upstream dspace-5_x: https://github.com/DSpace/DSpace/pull/1669
• Looks like -colorspace sRGB alone isn’t enough, we need to use profiles:

$ convert -thumbnail 300x300 -flatten -profile /opt/brew/Cellar/ghostscript/9.20/share/ghostscript/9.20/iccprofiles/default_cmyk.icc -profile /opt/brew/Cellar/ghostscript/9.20/share/ghostscript/9.20/iccprofiles/default_rgb.icc alc_contrastes_desafios.pdf\[0\] alc_contrastes_desafios.pdf.jpg

• This is a great resource describing the color stuff: http://www.imagemagick.org/Usage/formats/#profiles
• Somehow we need to detect the color system being used by the input file and handle each case differently
• This is trivial with identify (even by the Java ImageMagick API):

$ identify -format '%r\n' alc_contrastes_desafios.pdf\[0\]
DirectClass CMYK
$ identify -format '%r\n' Africa\ group\ of\ negotiators.pdf\[0\]
DirectClass sRGB Alpha