Encoding to JPEG transfer syntaxes

[Enet4]

Decoding JPEG-based transfer syntaxes is already supported, but support for encoding a native DICOM object to JPEG would be good to have.

In a first phase, this amounts to implementing the encode method of the PixelRWAdapter implementation for JPEGAdapter.

• [x] Encode to JPEG baseline (done via #303)
• [ ] Encode to JPEG extended (12-bit)
• [ ] Encode to JPEG lossless
• [x] Encode to JPEG-LS (#573)
• [ ] Encode to JPEG 2000
• [ ] Encode to HTJ2K
• [x] Encode to JPEG XL (#571 via zune-jpegxl, lossless encoding only)

[Almeida-a]

I think I can take this issue.

Is there a way to test this new implementation after it is finished?

[Enet4]

Great!

Is there a way to test this new implementation after it is finished?

By lack of a proper transcoding module (efforts are ongoing!), we can test the adapter in isolation by encoding one of the test files, reading the output as a JPEG file using the decoder and checking whether some meta-properties are correct (width, height...). Pixel data check could be done too, but we would need to allow an error margin to account for loss.