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Add notes for 2018-12-03

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Alan Orth
2018-12-03 12:35:27 +02:00
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@ -80,4 +80,61 @@ or(
)
```
## 2018-12-03
- I looked at the DSpace Ghostscript issue more and it seems to only affect certain PDFs...
- I can successfully generate a thumbnail for another recent item ([10568/98394](https://hdl.handle.net/10568/98394)), but not for [10568/98930](https://hdl.handle.net/10568/98390)
- Even manually on my Arch Linux desktop with ghostscript 9.26-1 and the `pngalpha` device, I can generate a thumbnail for the first one (10568/98394):
```
$ gs -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 -sDEVICE=pngalpha -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -r72x72 -dFirstPage=1 -dLastPage=1 -sOutputFile=/tmp/out%d -f/home/aorth/Desktop/Info\ Note\ Mainstreaming\ gender\ and\ social\ differentiation\ into\ CCAFS\ research\ activities\ in\ West\ Africa-converted.pdf
```
- So it seems to be something about the PDFs themselves, perhaps related to alpha support?
- The first item (10568/98394) has the following information:
```
$ identify Info\ Note\ Mainstreaming\ gender\ and\ social\ differentiation\ into\ CCAFS\ research\ activities\ in\ West\ Africa-converted.pdf\[0\]
Info Note Mainstreaming gender and social differentiation into CCAFS research activities in West Africa-converted.pdf[0]=>Info Note Mainstreaming gender and social differentiation into CCAFS research activities in West Africa-converted.pdf PDF 595x841 595x841+0+0 16-bit sRGB 107443B 0.000u 0:00.000
identify: CorruptImageProfile `xmp' @ warning/profile.c/SetImageProfileInternal/1746.
```
- And wow, I can't even run ImageMagick's `identify` on the first page of the second item (10568/98930):
```
$ identify Food\ safety\ Kenya\ fruits.pdf\[0\]
zsh: abort (core dumped) identify Food\ safety\ Kenya\ fruits.pdf\[0\]
```
- But with GraphicsMagick's `identify` it works:
```
$ gm identify Food\ safety\ Kenya\ fruits.pdf\[0\]
DEBUG: FC_WEIGHT didn't match
Food safety Kenya fruits.pdf PDF 612x792+0+0 DirectClass 8-bit 1.4Mi 0.000u 0m:0.000002s
```
- Interesting that ImageMagick's `identify` *does* work if you do not specify a page, perhaps as [alluded to in the recent Ghostscript bug report](https://bugs.ghostscript.com/show_bug.cgi?id=699815):
```
$ identify Food\ safety\ Kenya\ fruits.pdf
Food safety Kenya fruits.pdf[0] PDF 612x792 612x792+0+0 16-bit sRGB 64626B 0.010u 0:00.009
Food safety Kenya fruits.pdf[1] PDF 612x792 612x792+0+0 16-bit sRGB 64626B 0.010u 0:00.009
Food safety Kenya fruits.pdf[2] PDF 612x792 612x792+0+0 16-bit sRGB 64626B 0.010u 0:00.009
Food safety Kenya fruits.pdf[3] PDF 612x792 612x792+0+0 16-bit sRGB 64626B 0.010u 0:00.009
Food safety Kenya fruits.pdf[4] PDF 612x792 612x792+0+0 16-bit sRGB 64626B 0.010u 0:00.009
identify: CorruptImageProfile `xmp' @ warning/profile.c/SetImageProfileInternal/1746.
```
- As I expected, ImageMagick cannot generate a thumbnail, but GraphicsMagick can (though it looks like crap):
```
$ convert Food\ safety\ Kenya\ fruits.pdf\[0\] -thumbnail 600x600 -flatten Food\ safety\ Kenya\ fruits.pdf.jpg
zsh: abort (core dumped) convert Food\ safety\ Kenya\ fruits.pdf\[0\] -thumbnail 600x600 -flatten
$ gm convert Food\ safety\ Kenya\ fruits.pdf\[0\] -thumbnail 600x600 -flatten Food\ safety\ Kenya\ fruits.pdf.jpg
DEBUG: FC_WEIGHT didn't match
```
- I inspected the troublesome PDF using [jhove](http://jhove.openpreservation.org/) and noticed that it is using `ISO PDF/A-1, Level B` and the other one doesn't list a profile, though I don't think this is relevant
<!-- vim: set sw=2 ts=2: -->