Nico Weber c4780f4ee1 image: Add an --invert-cmyk option ...

This is useful for working with CMYK jpegs extracted from PDFs
by mutool. CMYK channels for jpegs in PDFs are inverted compared to
CMYK channels in standalone jpegs (!), and mutool doesn't compensate
for that.

You can now do:

    mutool extract  ~/Downloads/0000/0000711.pdf 461

Followed by:

    Build/lagom/bin/image -o out.png \
        --invert-cmyk \
        --assign-color-profile \
            Build/lagom/Root/res/icc/Adobe/CMYK/USWebCoatedSWOP.icc \
        --convert-to-color-profile serenity-sRGB.icc \
        cmyk.jpg

Doesn't exactly roll off the keyboard, but at least it's possible.

(We should probably add an implicit default CMYK color profile if
the input file doesn't have one, and assume conversion to sRGB when
saving to a format that can only store RGB.)

2024-02-04 21:34:53 +01:00

11 KiB

Raw Blame History

View Raw