Tap distance threshold

[maxkfranz]

Dragging a node should not start until the user has dragged beyond a certain distance. This allows for easier tapping and selecting.

Analogous behaviour should occur for tapping and panning on the background.

[maxkfranz]

Labelling as bug and advancing to 2.3.6 milestone -- not because it's technically a bug per se, but because without this behaviour things are less easy for users. So, we should address this as soon as possible.

[maxkfranz]

TODO more testing

[maxkfranz]

I'm going to close this, as it seems to be working from my testing. We can reopen if there is any issue. It may be nice to experiment with different threshold values before release.

[maxkfranz]

TODO threshold should not change relative node grab position. This doesn't break anything, but it can be disconcerting to the user.

[maxkfranz]

@ktei Would you please experiment with different tap threshold values? I don't think think programmers would want to set this value manually, but I would like to ensure that the values set in core.js are appropriate.

You mentioned that you had users who had trouble without the tap threshold, so would you mind testing with those users to see if perhaps higher values are needed? Thanks!

[ktei]

@maxkfranz I think the original issue one of the users mentioned is this: he wishes to select a node (we highlight node border for selected nodes using stylesheet) immediately after he clicks on the node. But as you know sometimes you click on a node with a little bit dragging it, which makes the system think you are dragging so the node will not be selected (highlighted), because the selection occurs in mouseup event. So I changed a bit code to make selection happen in mouse down regardless of dragging or not, as long as the node is hit. The tap distance, if I understand it correctly, is to tolerate users with fat fingers in case that can't tap on a node precisely. As far as I am concerned, none of our users has reported this kind of issue yet. Not sure if this helps you?

[maxkfranz]

The tap threshold solves the issue you describe by not starting drag actions until the user has dragged beyond a certain distance. This means that if you drag a node a little bit, it isn't dragged and it's detected as a normal tap (and select).

If you select on mousedown, you will run into trouble eventually -- as you have restricted the possible set of interaction states.

[ktei]

Okay. I think I misunderstood the tap distance. I need to get your changes and have a try. I will let you know soon.

[maxkfranz]

Perhaps TODO:

Threshold on background tap operations; makes things like unselect easier.

[ktei]

Hi, @maxkfranz
I just pulled your changes to my forked repository. I think it's working fine. I'm going to push that changes to production soon I think. I do think you can provide the tap distance option to developer users, but maybe warn them in the documentation that this is preferred to stay unchanged unless they know what they're doing?

[maxkfranz]

That's fair, but perhaps it should be split into two options: One option for mouse and one for touch. I think the touch case and the mouse case need separate values, because the input accuracy is different between those cases.

[maxkfranz]

@ktei I think that should be everything. From my testing everything seems OK. Please try things out, and if it looks good I can make the release.