Add support for jpeg-recompress from danielgtaylor/jpeg-archive

[wjordan]

Adds support for the jpeg-recompress utility from danielgtaylor/jpeg-archive:

jpeg-recompress

Compress JPEGs by re-encoding to the smallest JPEG quality while keeping perceived visual quality the same and by making sure huffman tables are optimized.

I've set the program to be disabled by default. It is enabled by using the --jpegoptim-max-quality N option to set a JPEG quality preset other than lossless.

Other configuration options are available aside from the quality preset, but I haven't added them to the image_optim options:

    -t, --target [arg]            Set target quality [0.9999]
    -n, --min [arg]               Minimum JPEG quality [40]
    -x, --max [arg]               Maximum JPEG quality [95]
    -l, --loops [arg]             Set the number of runs to attempt [6]
    -a, --accurate                Favor accuracy over speed
    -m, --method [arg]            Set comparison method to one of 'mpe', 'ssim', 'ms-ssim', 'smallfry' [ssim]
    -s, --strip                   Strip metadata
    -d, --defish [arg]            Set defish strength [0.0]
    -z, --zoom [arg]              Set defish zoom [1.0]

[toy]

Looks interesting, thanks for contribution.
I see that you are using %i which doesn't work in ruby < 2.0.
Also you didn't change comments for class and run_order method.
I'll check how it works.

[toy]

Why copy instead of using src for input and dst for output in arguments?

[wjordan]

No intentional reason, I think I just used jpeg_optim as a starter template, I can probably remove this.

[toy]

Things I've notices:

• You did not add changelog entry.
• I've commented on line where you copy src to dst and then use dst for both input and output.
• Worker should use --no-copy argument so no useless data transfer happen.

Not sure about other arguments, with --accurate worker was much slower and did not optimise as good, but there was no difference in quality loss measured by root mean squared error.

• Also I am still thinking if it would be better to have global option like allow_lossy which will be passed to all workers and can be used in jpegoptim and pngquant.

[toy]

@wjordan Once more thanks for contribution, merged and released v0.19.0

[wjordan]

Thanks for finishing up and integrating the contribution! Glad it was helpful. I think the allow_lossy option is a great addition to the program.