Zooming gesture detection does not trigger on whole view

[Ecconia]

The SudoQ app comes with a zoom support.
That means there is a pinch gesture detection and two nested ScrollViews for X/Y scrolling of the Sudoku field.

Expected:

• Pinching works always on the whole gray area (- margin around), to zoom into the Sudoku field.
• When moving my finger horizontal/vertically/diagonally, the Sudoku field moves accordingly.

Encountered / Issue:

• The pinch gesture only works on the gray background.
• The moving only works on the gray background.
• Starting of either gesture has to happen on the gray background, once started one can move the fingers everywhere.

This makes the zooming pretty much unusable.

Environment:

• Android: 9

[Ecconia]

On my local fork, I was able to fix the zooming and scrolling properly.

However there are more things connected to that. For example is the zooming not smooth and the "focus" point not where it should be.

[timo-a]

Thanks for finding that! Zoom was never smooth but before v1.2.0 it was working in cells as well as on the gray background.
(I have confirmed that it worked in 1.1.0c, I cannot build 1.1.1) I suspect it stopped working with abadbb0 when I merged feature/gesture-for-notes where I refactored the input of notes and entries.

[Ecconia]

I just finished the first fix (on my fork). Commit: Ecconia@a57ceb1

• That pretty much fixes the zooming and scrolling on non-background views.
• It fixes the crash when zooming on the action-tree.
• It gets rid of some current variable and the center code in scrollTo which the ActionTreeController uses.
• Improves, that scrolling on the Action-Tree might click an Element of it on ACTION_DOWN.

The remaining issues are pretty much the focus and smoothness of the zooming:

• I did also find the issue for the wrong focus position.
• The smoothness of zooming seems to be quite difficult to improve, without changing the way the whole zoom-view works.
• There is also the issue, that one cannot scroll while zooming.

But due to reasons elaborated in the language PR (this is time consuming and not perfectly solved yet), I will not create a PR for this issue.