Add transform mode button for layers

[dalthviz]

References and relevant issues

Part of #3975

Description

Add a button to activate the layers transform mode. Also, add a way to reset the transform to the initial value set at layer creation (reset trigger via Alt + Left mouse click over the transform mode button):

A preview:

Notes/TODOs:

• Icon selection/definition needs to be done (in progress)
  • Possible icon design at GUI element to set layer transforms (scale/ translate) #3975 (comment)
  • Selected icon at GUI element to set layer transforms (scale/ translate) #3975 (comment)
• Implemented the Alt-click approach to trigger a reset with a confirmation dialog but happy to check any other alternatives/ideas

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.44%. Comparing base (98c2e0f) to head (a9c116c).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6794      +/-   ##
==========================================
- Coverage   92.48%   92.44%   -0.04%     
==========================================
  Files         612      612              
  Lines       55165    55229      +64     
==========================================
+ Hits        51018    51057      +39     
- Misses       4147     4172      +25     

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[psobolewskiPhD]

Does pre-pending a new line char here work to make the total tooltip 2 lines?

[dalthviz]

Yep, doing something like:

Suggested change

	extra_tooltip_text=trans._('(use Alt-Left mouse click to reset)'),
	extra_tooltip_text=trans._('\n(use Alt-Left mouse click to reset)'),

makes things look like this:

[psobolewskiPhD]

yes! with the new line, maybe we don't need the parens and the use?
so just
Alt-Left mouse click to reset
I think that's still clear, but a bit more concise.

[dalthviz]

Just in case, a preview:

[brisvag]

Nice! Now wondering if we should default to adding a newline for everything before the extra_tooltip_text...

[dalthviz]

That makes sense! From a quick check seems like the only other button that has some extra text is pan/zoom:

Maybe something like Temporarily re-enable by holding Space could be used as text in case the extra text is added always in a new line?

Also, should an issue be made to tackle that later or maybe is something worthy to be done here?

[psobolewskiPhD]

I mean I feel like the new line would be safe as a default...
but I don't think I would change it in this PR--if at all. It's easy to add the new line, harder to remove it if someone does want a one-liner.

[dalthviz]

Created #6907 to further check the new line behavior related to binding actions to buttons. For the moment, I think things here can be left as they are. Another option could be to change the pan/zoom extra text to include a new line so something like:

self.panzoom_button = self._radio_button(
            layer,
            'pan_zoom',
            self.MODE.PAN_ZOOM,
            False,
            self.PAN_ZOOM_ACTION_NAME,
            extra_tooltip_text=trans._('\n(or hold Space)'),
            checked=True,
        )

Or using the text suggestion above:

self.panzoom_button = self._radio_button(
            layer,
            'pan_zoom',
            self.MODE.PAN_ZOOM,
            False,
            self.PAN_ZOOM_ACTION_NAME,
            extra_tooltip_text=trans._('\nTemporarily re-enable by holding Space'),
            checked=True,
        )

Let me know what do you think!

[psobolewskiPhD]

I like this a lot. Looks like a lot of changes at first, but it's mostly docstrings and refactoring that makes things simpler in the long run.

It is strange at first to see the tool icons for image layers, but it opens the possibility of other tools there (Crop? Histogram?)

Played with it locally -- found bug in Labels transform, made issue -- and it works nicely. We'll need to make a docs PR to document the change.

[brisvag]

It is strange at first to see the tool icons for image layers, but it opens the possibility of other tools there (Crop? Histogram?)

<3

[dalthviz]

We'll need to make a docs PR to document the change.

Is there any specific place in the docs where things need to be added or changed? Not completly sure what needs to be done but happy to help with that 👍

[psobolewskiPhD]

Gah! I realized something: transform mode is 2D only, so we need the button be disabled if viewer is in 3D.

Edit: this is already the case for the Shapes layer, because the other buttons were behaving that way. Looks like self._EDIT_BUTTONS could be the way to go.

[psobolewskiPhD]

I think we'll need to write up a description of Transform mode somewhere -- viewer guide? I'd hate to duplicate it for every layer, need to think about this -- and then inform that the icon activates that mode and that alt-click resets transforms.

[dalthviz]

I think we'll need to write up a description of Transform mode somewhere -- viewer guide? I'd hate to duplicate it for every layer, need to think about this

Created napari/docs#420 as quick draft but checking seems like probably some info should be also added over the layer types detailed descriptions at https://github.com/napari/docs/tree/main/docs/howtos/layers. Maybe to prevent duplication a general buttons (and even maybe controls) description should be added at https://github.com/napari/docs/blob/main/docs/howtos/layers/index.md ?