Input harvesting not working with multiple ImgPluses

[hinerm]

If I have a script with multiple @ImgPlus input parameters and multiple images open, the input harvester seems to only recognize the first image as an input option, although it knows there are two options.

I would expect to see blobs.gif and blobs-1.gif as options in the combo box. They do indeed seem to be the same options as I tried selecting both first and second entries as the outImage parameter and get a complaint from Ops that the input and output params are the same. (slight chance it is non-deterministic and I just keep getting unlucky and picking the "first" image)

[imagejan]

Related: imagej/imagej-legacy#171

[hinerm]

OK part of the problem is definitely that registration of the ImgPlus instances happens too late for the input selection when there are multiple inputs.

If I open clown and blobs and the first script I try to run is:

#@ ImgPlus in1
#@ ImgPlus in2


println(in1)
println(in2)

Then I will actually get "An ImgPlus is required but none is available!" error.

If I:

1. Remove one of the parameters from the script
2. Select clown as active
3. Run the script
4. Select blobs as active (interchangeable with 2)
5. Run the script again
6. Restore the removed script parameter
7. Run the script one more time

then both clown and blobs will be available as parameters (although listed twice).

I'm guessing we're using a SingleInputPreprocessor and it either isn't working as intended or is insufficient.

[hinerm]

OK, right now the ActiveImagePreprocessor asks the ImageDisplayService for the current image, which is where the conversion happens.

So whenever multiple image inputs are requested we need to make sure getImageDisplays is called.

[hinerm]

So whenever multiple image inputs are requested we need to make sure getImageDisplays is called.

This is maybe not true. It just occurred to me to try non-ImgPlus inputs and it does work as expected with multiple Dataset or Img inputs. It's just ImgPlus that breaks.

[hinerm]

Almost certainly because the converter we have is ImagePlusToDataset. The ConvertService looks for assignable converter output types and Dataset is an Img but not an ImgPlus 🙄🙄🙄🙄🙄

[imagejan]

Regarding conversion of various image types, see also imagej/imagej-legacy#229 (and imagej/imagej-legacy#186 and imagej/imagej-ops#54 by extension).