[ImageJ-devel] @parameter choice update in component callback

[Adrian Daerr]

Hi Curtis, Felix, Jan, and others,

In the CommandWithPreview tutorial example[*] that Curtis sent to
the list a few weeks back, there is a @Parameter which is
initialised to a value depending on the initialisation of another
parameter:

@Parameter private ImagePlus imp;

@Parameter(persist = false, initializer = "initTitle") private String 
title;

/** Initializes the {@link #title} parameter. */
protected void initTitle() {
	title = initialTitle = imp.getTitle();
}

[*]
https://github.com/imagej/imagej-tutorials/blob/master/commands-with-preview/src/main/java/CommandWithPreview.java

Doesn't that allow doing what Felix would like to do, by
populating the combobox through such an initialiser ?

Are the parameters populated/initialised in the order they
appear? In particular, is the initialisation done serially or can
there be parallel execution of initialisers ? I ask because I
have parameters a, b, c whose initialisation depend on a common
calculation (depending on the image gotten through a previous
@Parameter ImagePlus imp): can I do this calculation in the
initialiser for the first parameter a, and then in the
initialisers of b and c rely on the fact that the calculation was
already done ?

cheers,
Adrian



On Thu, 20 Aug 2015 17:13:11 -0500
  Curtis Rueden <ctrueden at wisc.edu> wrote:
> Hi Felix, Jan and everyone,
> 
>> I couldn’t find any hint that it is possible to update the choices 
>>of
>> a parameter (declared with the annotator) in a callback that for
>> another parameter.
> 
> It is possible to dynamically adjust parameters from Java code [1]. 
>You can
> also dynamically add and remove parameters. Such commands extend the
> DynamicCommand class.
> 
> There are many examples currently in the imagej-plugins-commands 
>project;
> e.g.:
> https://github.com/imagej/imagej-plugins-commands/blob/imagej-plugins-commands-0.5.1/src/main/java/net/imagej/plugins/commands/restructure/AddAxis.java
> 
> However, a couple of notes:
> 
> - This pattern makes the command less reusable from other contexts, 
>because
> some contexts require a priori knowledge about the number and types 
>of
> input and output parameters.
> 
> - The user interface currently does not properly refresh the input
> harvester dialog if changes are made to parameters from a callback. 
>So
> while you can technically do things like change the choices array of 
>a
> multiple-choice input, the user will not actually see it.
> 
> - What does work currently is to determine the multiple-choice 
>values at
> initialization time, based on the values of parameters which have 
>already
> been populated earlier, such as an active dataset. This is what many 
>of the
> DynamicCommand implementations in imagej-plugins-commands do.
> 
> Really, there are _five_ different classes of commands here:
> 
> 1) Totally fixed, with inputs and outputs known in advance.
> 2) Updates parameter attributes (such as choices—but not # or type 
>of
> inputs/outputs) once during initialization.
> 3) Updates parameter number and type (i.e., adding/removing 
>inputs/outputs)
> once during initialization.
> 4) Updates parameter attributes repeatedly e.g. during callbacks.
> 5) Updates parameter number and type repeatedly e.g. during 
>callbacks.
> 
> Of these, type #1 is most desirable for a variety of reasons. 
>Failing that,
> types #2 and #3 can be done right now using DynamicCommand and it 
>works
> properly from the ImageJ UI—but not from other contexts like 
>CellProfiler,
> KNIME, etc. Types #4 and #5 can also be coded but will not work 
>properly
> from the UI in ImageJ because the input harvester is not rebuilt on
> callbacks.
> 
> See also:
> * https://github.com/scijava/scijava-common/issues/42
> * https://github.com/scijava/scijava-common/issues/43
> * https://github.com/CellProfiler/CellProfiler/issues/647
> 
> Regards,
> Curtis
> 
> [1] Dynamically updating parameters from scripts would be a 
>different
> story. No plans to do that any time soon...
> 
> On Thu, Aug 20, 2015 at 6:50 AM, Jan Eglinger 
><jan.eglinger at gmail.com>
> wrote:
> 
>> Hi Felix and all,
>>
>> On 20.08.2015 10:06, MEYENHOFER Felix wrote:
>>
>>> I couldn’t find any hint that it is possible to update the choices 
>>>of a
>>> parameter (declared with the annotator) in a callback that for 
>>>another
>>> parameter. For example; I have a file chooser and once a file hase 
>>>been
>>> chosen, I want to read some file metadata and then update the 
>>>choices of
>>> the combobox that allows to select the images series.
>>> Since I could not figure a way to do it, I wanted to ask here if it 
>>>is
>>> possible at all?
>>>
>>>
>> I think dynamic adjustment of parameters isn't possible currently, 
>>but I
>> agree that it would be a great thing to have.
>>
>> I know quite some use cases where either a DialogListener or a 
>>series of
>> subsequent dialogs are used in ImageJ 1.x plugins to adjust 
>>parameter
>> choice to previously harvested input.
>>
>> Furthermore, is it possible to get a directory chooser instead of a 
>>file
>>> chooser in the configuration dialog of a command using the 
>>>@Parameter
>>> annotation?
>>>
>>>
>> Yes, by using the
>>     style = "directory"
>> attribute. See *Templates > Python > Process Folder* in the script 
>>editor,
>> and this related discussion:
>>   https://github.com/imagej/imagej-legacy/pull/114
>>
>> Best,
>> Jan
>>
>>
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>>

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