Preprocessor for photos to display on the Inky Impression eInk display

I made this thing to process a bunch of my photos for display on the Inky Impression 7 color eInk display.

It does the following:

• Converts all HEIC files in the input directory to JPGs (also in the input directory)
  • Make sure none of your input files have weird filenames because I haven't bothered to escape any characters in the call to ImageMagick.
• For each photo:
  • Runs facial detection
  • Determines a center point for cropping, which is the center of all detected faces or just the center of the photo if no faces were detected.
  • Crops the photo according to the above to fit the target display.
  • Dithers the photo to match the defined color palette (Inky Impression by default)
  • Writes the resulting image to the output directory

You will need Java and Maven for this because I haven't bothered to upload a JAR anywhere. You will also need ImageMagick installed for the HEIC conversion to work.

Run mvn clean compile exec:java -Dexec.args="$input $output" where input is the relative path to your directory of input images, and output is the relative path to where you want your output images.

I was too lazy to extract most config to a file or args. All parameters are constants in code that you can diddle with. See the constants at the top of Main.kt and net.djvk.inkyPhotoPrep.PatternDitherer especially.

1. Why didn't you do this in Python, where face detection is easier to use and there's already sample code from Pimoroni for dithering?
   1. No good reason. I usually prefer Kotlin and can generally find a Java library for any of my purposes, but that kind of backfired this time, and I was too deep in the ol' sunk cost fallacy to change course.
2. Why is Maven installing a zillion versions of JavaCPP?
   1. Maven isn't great at architecture-specific dependencies, so it's just carpet bombing. See here for instructions on how to limit your downloads.