Looping: It is too easy to accidentally trigger a looping region by clicking on the timeline

[Tantacrul]

Describe the bug
When some users try to use Quick-Play by clicking on the timeline and inadvertently moving the mouse a little, they accidentally create a very tiny loop region, which in turn, activates the loop button and causes a degree of irritation. We've heard enough complaints about it to warrant a fix soon. On the plus side, I think the fix is probably very easy.

Expected behaviour
The threshold for dragging needs to be larger, so that a loop region isn't created when the user clicks and drags just a pixel or two. We will need to set a threshold of something like 10-20 pixels (possibly more... but we'll need to test). It is extremely unlikely that a user would set a very very small loop region only a few pixels apart, so we can probably bump up the
threshold to avoid the possibility of contradicting the user's intention.

I can help test to make sure we get the threshold just right. :)

[petersampsonaudacity]

We have had lots of complaints about this on the Forum - so fixing this would be very helpful to such users.

[petersampsonaudacity]

I have been testing on older Audacity versus new 3.1 Audacity with new Audacity with new looping.

One of the reasons that I think this issue is egregious and annoying to users is that with earlier Audacity when the user accidentally moved their mouse in this way it didn't just create a play/loop region - it actually played the small Timeline range.

I suspect that it the apparent lack of anything really happening apart from a visual range (the new loop range) that surprises and confuses users.

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I've been thinking a lot more about this and I think it would be much-improved if user controls when looping is active or not by the use of the Loop button:

a) when active, "down", then click&drag (for a reasonable number of pixels) in the Timeline creates a loop region,

b) when "up", inactive, then no loop region is shown and Timeline simply does QuickPlay - and no loop regions can be created.

The tolerance zone would still be needed though as looping users with their Loop button down may still well want to use QuickPlay as well.

[petersampsonaudacity]

On a close-cousin related issue see this Forum post:
https://forum.audacityteam.org/viewtopic.php?f=46&t=121807

Thu user here is confused as they are trying to create a "selection" for editing but they are actually creating a loop region in the Timeline.

@Tantacrul flagging this as a UX issue

[petersampsonaudacity]

And here's another example from today of a posting from a user on the Forum wjo is frustrated by this:

Another first-time poster asking for the Looping controls to be disable-able. I need Audacity 3+ to fix a major issue I was having with 24-bit audio with version 2, but the looping UI is driving me a little crazy. As I use Audacity to splice many clips together into 1 file, I am constantly skipping around in a track by clicking at the top of the timeline area where it immediately plays starting from wherever you click. But I have never been the world's most accurate clicker and now with the looping feature, I am regularly clicking a little bit too low and setting a looping region instead of just playing. It is quite frustrating. Hopefully it will get easier as I get used to the new version but I would definitely prefer to be able to disable this feature. Thanks for the wonderful software!

See: https://forum.audacityteam.org/viewtopic.php?f=70&t=121230&p=440571

And I am also a similarly frustrated user about this - it happened to me several times yesterday while I was editing (and I even know about this problem).

[SteveDaulton]

We will need to set a threshold of something like 10-20 pixels (possibly more... but we'll need to test).

The threshold that I set in the old Timeline Quick Play seemed to work well. I don't recall the exact size - it was pretty small, but the absence of complaints suggests that it was enough, while still allowing users to mark short loops.

Update: looks like it was +/- 4 px.
May need to consider hidpi now that it has become much more common.

[petersampsonaudacity]

I just tested @Paul-Licameli 's build for this on W10
Don't change play region for very short mouse drags CMake Build #3257
https://github.com/audacity/audacity/actions/runs/1530570708

Testing shows (to me at least) the the tolerance region works well, Small moves in either direction do not create a loop region and when the mouse button is released Quick-Play starts. Looks good to me.

@Paul-Licameli Out if interest, Paul, what size is the tolerance, how many pixels?

[Paul-Licameli]

I just tested @Paul-Licameli 's build for this on W10 Don't change play region for very short mouse drags CMake Build #3257 https://github.com/audacity/audacity/actions/runs/1530570708

Testing shows (to me at least) the the tolerance region works well, Small moves in either direction do not create a loop region and when the mouse button is released Quick-Play starts. Looks good to me.

@Paul-Licameli Out if interest, Paul, what size is the tolerance, how many pixels?

Up to four pixels either side of the mark. That was how it used to work, happily, in the time ruler, and so I used the same tolerance.