Use offset for touch dragging

[zepumph]

While working on issues from dev testing, I noticed that my finger completely covers up the particle view while dragging. In other spots in code we use an offset to still be able to see the dragging node, like AbstractCoinTermNode. I think we should play around with this a bit.

Note the code is in shred so I'll just make an option like "touchOffset"

[zepumph]

This was simple enough to do that I decided to implement it as the design conversation. @ariel-phet, do you like the offset applied on main? We can make it less or more, or get rid of it. I personally feel like it is an improvement.

[zepumph]

@Nancy-Salpepi FYI in case you have thoughts.

[Nancy-Salpepi]

@zepumph I think this is great. It is more user friendly for sure.

[Nancy-Salpepi]

Wondering if we need this much offset @zepumph? I see that in Expression Exchange it is a lot less and doesn't look so jumpy.

[ariel-phet]

@zepumph @Nancy-Salpepi I don't have access to a great touch device currently.

I think the idea of an offset is appropriate, and in this case I think @Nancy-Salpepi is well qualified to make the call of what looks best. I would say fine tune with her!

[zepumph]

To find the perfect number, I made a query parameter ?particleTouchOffset=20. @Nancy-Salpepi you tested with a value of 30 and thought it was a bit too much. The current default is 20. Let me know what you want the value to be.

Wondering if we need this much offset @zepumph? I see that in Expression Exchange it is a lot less and doesn't look so jumpy.

In expression exchange we have a bit of an easier time because the object is bigger, so you don't have to move it as much to make it visible above your finger. The particles are pretty tiny.

I personally don't mind a jump too much if it means that the particle is clearly visible as I drag. I tried a value of 15 and couldn't really see the particle still (but it also didn't jump)! That said I have fat fingers.

I don't really have an opinion here, but wanted to give you the data I found while working on this. Let me know what you like and we should do that.

[Nancy-Salpepi]

@zepumph the behavior I see today with ?particleTouchOffset=30 is not the same as the other day. The particle is much closer to my fingertip and not jumpy. Was there another change that may have cause this?

[zepumph]

Hmmm, not that I know of. Weird!

[Nancy-Salpepi]

Is the behavior the same for you today as it was the other day @zepumph?

[Nancy-Salpepi]

The current behavior I am seeing with ?particleTouchOffset=30 looks good to me. What I initially saw and commented on in https://github.com/phetsims/build-a-nucleus/issues/197#issuecomment-1724334623 was behavior similar to ?particleTouchOffset=70. Not sure why there was this inconsistency.

[zepumph]

Is the behavior the same for you today as it was the other day @zepumph?

Ahh shoot. I totally gas-lit you. I thought that I originally set it to 30, but I actually set it to 60 before. So sorry. It is 30 now and the query parameter has been removed. Do you like it?

[zepumph]

After discussing with @Nancy-Salpepi, we brought back the query parameter to play with more. Note that this really depends on the size of the window. A small sim will definitely hide at 30, but 30 in a full screen sim seems really nice on my screen. @Nancy-Salpepi let me know what you like!

[Nancy-Salpepi]

I tested on both the iPad and iPhone. Once I zoom in a bit, my finger doesn't hide the particle at 30 on the phone. Let's stick with 30. I think I decided what house to buy and planned my entire wedding faster than I made this decision 😂.

[Luisav1]

@zepumph and I removed the touchOffset query parameter and made it permanently 30. Closing.