Panning can result in zooming on touchscreens

[quincylvania]

When using iD on iOS, I can often enter a state where simply swiping to pan ends up zooming the screen. This state makes navigating significantly harder and I have not found a way to get out of it.

[BjornRasmussen]

Same for me with Chrome on Android! The "Solution" is reloading.

[quincylvania]

I've been looking into this while revamping touch interaction for #5505. I'm pretty sure the issue is that a touch leaves the screen without iD logging it as gone, so subsequent swipes are interpreted as two-finger pinches instead of one-finger pans. This commit likely fixed it by listening for all ended or canceled touches at the window level instead of the map level, but I couldn't reproduce the problem reliably so I'm not certain. We'll have to do extensive test mapping on the preview site on touch devices to suss out touch interaction bugs before releasing.

[quincylvania]

This is still happening…

I think we need to be more careful about using stopPropagation on pointerup events since stuck pointers can occur if the map zoom/pan handler doesn't receive this event.

[quincylvania]

I haven't seen this bug in quite some time, so I'm hoping I finally fixed all occurrences. We must continue to stay vigilant… 🕵️‍♂️🐛

[BjornRasmussen]

As of 5 minutes ago on the preview site, this is still an issue. I got stuck and couldn't escape. I am using Firefox, windows 10.

[quincylvania]

@BjornRasmussen Any chance you have steps to reproduce this?

[BjornRasmussen]

No, unfortunately not. It just happened to me the first time I tested out the new iD

[cloudrac3r]

This is unfortunately still an issue. (Please re-open this!) I've never touched the iD editor source code before, so I'd be interested to know, is there a way I can open some sort of debug view, or inspect the touch state, so that I can see whether iD thinks that a touch is stuck?

From how it feels to use the editor while in the touch state, I think it is behaving like a previous touch was stuck, but without a way to see iD's interpretation of the touch state, I don't expect I would be able to figure out the steps to reproduce.

I am familiar with general web development and I'd like to do whatever I can to help fix this.

[cloudrac3r]

I have discovered that it seems to happen while drawing areas if something goes wrong drawing the area (like the area crossing over itself), however, I still can't consistently trigger it.

I can always remove the stuck touch event by reloading the page, and I think also by saving the current working changeset. It seems like I can sometimes (always?) remove the stuck touch event by also pressing M to activate the move tool, picking up an area, and putting it down again. I will keep posting if I figure out anything else.

I'm using my finger here to touch. Using a digital stylus to touch the screen seems to produce other inconsistencies, so I'm not opening that can of worms yet.

[cloudrac3r]

I can remove the stuck touch event by pressing M while an area is selected to activate the move tool, and then clicking the mouse button (without moving it) to complete a useless move. However, if I use the Enter or Esc keyboard keys to end the move operation, it does not undo the stuck touch event.

I should mention that I've been using a touchscreen laptop running Firefox on KDE Linux.

[1ec5]

You may be seeing something similar to #8649. Please open a new issue, since gesture handling changed significantly since this issue was closed.