[Doc]: Garbled menu widget example output

[StefRe]

Documentation Link

https://matplotlib.org/devdocs/gallery/widgets/menu.html

Problem

Suggested improvement

Should be as in version 3.4 and before:

[ksunden]

This does not show up poorly when I run it locally, so not totally sure why it is going wrong on the docs...

[StefRe]

Right: sphx_glr_menu_001.png is correct and only sphx_glr_menu_001_2_00x.png is poorly aligned.
So the issue is linked to saving the figure with dpi settings different from 100, probably caused by using the IdentityTransform to specify label positions.

[ksunden]

Ah... this is likely because the position, sizing, and padding values are specified in pixels in these examples, and not updated when the DPI changes... I know @QuLogic has had some thoughts towards similar problems in the past, so I will tag him in here.

[anntzer]

I suspect the "easy" fix would be to reuse the trick of https://matplotlib.org/devdocs/gallery/text_labels_and_annotations/rainbow_text.html to position texts relative to one another.

[StefRe]

I suspect the "easy" fix would be to reuse the trick of https://matplotlib.org/devdocs/gallery/text_labels_and_annotations/rainbow_text.html to position texts relative to one another.

While this solves the alignement issue I couldn't find a way to set all the text boxes to the same length without using get_window_extent. That's why I thought it would be easiest to just fake the output, see #27365.

[anntzer]

I guess I could imagine ways to fix that with custom Annotation subclasses that override get_window_extent, but I agree it's probably not really worth the complexity.

[jklymak]

The bbox could be converted to physical units and then all placement done in inches (or points) instead of pixels.

self.text_bbox = self.label.get_window_extent(
            fig.canvas.get_renderer())
self.text_bbox = fig.dpi_scale_trans.inverted().transform_bbox(self.text_bbox)

should be in inches. Then place things using fig.dpi_scale_trans rather than native pixels.

[StefRe]

Thanks @jklymak, will update the PR.