Add Last & Next zoom actions in layouts

[YoannQDQ]

• Fix Composer: Add "Zoom Last" and "Zoom Next" tools #22077
• Fix Add "zoom last" and "zoom next" buttons to layout navigation toolbar #58413

Description

Adapt QgsMapCanvas zoomToLastExtent / zoomToNextExtent to the QgsLayoutView.

[github-actions]

🪟 Windows builds ready!

Windows builds of this PR are available for testing here. Debug symbols for this build are available here.

(Built from commit dc9abb6)

[nyalldawson]

@YoannQDQ got a screencast or screenshot of this in action?

(It's great to see you back! 😁 🥳)

[YoannQDQ]

Done! Also fixed pan handling. By the way @nyalldawson I noticed I can no longer edit the label(s) on the issues I create. Could I maybe get the privilege back? Thanks.

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🪟 Windows builds

Download Windows builds of this PR for testing.
Debug symbols for this build are available here.
(Built from commit 47f2a6a)

🪟 Windows Qt6 builds

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(Built from commit 47f2a6a)

[nyalldawson]

Could all this logic be moved into the existing QgsLayoutView::viewChanged method? That should already be getting called whenever the view extent is changed, and already handles all the different ways this can happen.

That should also avoid the emit view()->extentChanged(); calls from other classes, which is rather fragile.

[YoannQDQ]

The problem is viewChanged is called every time the scrollbar moves. So dragging the scrollbar handle will trigger many MANY viewChanged calls, and we dont want them to clutter the zoom level history. Similarly, we do not want to add entries in the history while dragging the view with the pan tool.

[nyalldawson]

See above -- I'd handle this by using a timer to "collapse" extents which were used very close to each other.

[nyalldawson]

Any thoughts on this @YoannQDQ ?

[YoannQDQ]

I agree that the approach you suggested is better (it could also be applied to the map canvas imho). There's some additional consideration in the layout view since changing the scale will sometime make the scalebars appears/disappear, which in turn slightly change the view center and does not play well with the zoom/center history. It is on my backlog, but I haven't had the time to finalize it yet.

[nyalldawson]

For bonus points you could handle Qt::BackButton and Qt::ForwardButton in QgsLayoutView::mouseReleaseEvent, just like we do in QgsMapCanvas. 🥳

[github-actions]

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