Problem opening raw files

[jeroen]

If we try to read a raw file, we get a weird error about some temporary file not being available:

library(magick)
image_read("~/downloads/sample1.cr2")
#Error in magick_image_readpath(path, density, depth, strip, defines) : 
#  rsession: UnableToOpenBlob `/var/folders/l5/gk7g18z52876d4lbk9tjhr0c0000gn/T//RtmpBuqVbC/magick-K5GW65PQfGi4oL7liHocf05zvwrrzFDm.ppm': No such file or directory @ error/blob.c/OpenBlob/2924

@dlemstra do you have any guess what is going wrong? It looks like imagemagick copies/converts the cr2 file to a ppm file but then tries to read the wrong directory?

[dlemstra]

Maybe the delegate (most likely dcraw) that was used to execute failed to read the file and did not create an output file? Can you share the input file? And is this only happening in IM6 or can you reproduce it with IM7?

[jeroen]

This happens with both IM6 and IM7. I just used a sample cr2 file from here: https://filesamples.com/formats/cr2 but it also happens with any other cr2 file.

Do I need to enable dcraw specifically when building IM? Currently our builds do not have this delegate: https://github.com/homebrew/homebrew-core/blob/master/Formula/imagemagick.rb#L22-L75

[dlemstra]

You will either need libraw or dcraw for cr2 support.

[jeroen]

Ah okay, that is likely the problem then (it's not very clear from the error message 😅 )

[jeroen]

If I enable one of them, would you recommend libraw or dcraw?

[dlemstra]

The Windows build switched to libraw because it is then using a library directly instead of invoking a command through a shell.

[jeroen]

Fixed now by rebuilding imagemagick --with-raw and adding the libraw dependencies. Thanks @dlemstra !