map#isMoving

[mapsam]

Adds a method Map#isMoving that checks for the states of this.zooming, this.rotating, this.pitching, map.dragPan._active, and map.dragRotate._active. If any of them is true, the map is considered "moving" and the method returns true.

refs: #2792

TODO

• add tests, @lucaswoj I was thinking a test that looks something like this:

test('Map#isMoving returns expected results', function (t) {
    var map = createMap();
    var moving = false;
    var notMoving = false;

    function check () {
        if (map.isMoving()) moving = true;
        if (!map.isMoving()) notMoving = true;
    }

    map.on('load', function() {
        map.flyTo({center: [0, 0], zoom: 9});
    });

    map.on('render', check);

    map.on('moveend', function() {
        t.ok(moving, 'map was considered moving at one point');
        t.ok(notMoving, 'map was considered not moving at one point');
        t.end();
    });
});

But not having any luck with it so far.

cc @mollymerp @jfirebaugh

[lucaswoj]

Interesting that we need to mix the "interaction handler" layer of abstraction the "camera" layer of abstraction to compute Map#isMoving. Should Map#isMoving return true if the user starts a "drag rotate" interaction but doesn't actually rotate the map? Or if the user starts a "drag pan" interaction but doesn't pan the map?

[mapsam]

Good questions! I'm not familiar enough with these interactions enough to know the differences. The only way I was able to capture "pan" and "rotate" actions was through those dragPan and dragRotate parameters, though. Are there other places to look for them?

Should Map#isMoving return true if the user starts a "drag rotate" interaction but doesn't actually rotate the map?

I'm not sure - any chance you could provide a case where this happens?

[lucaswoj]

The only way I was able to capture "pan" and "rotate" actions was through those dragPan and dragRotate parameters, though. Are there other places to look for them?

We may need to create the place to look for this state by

• creating map.panning property
• ensuring that map.rotating and map.rotating works with the dragRotate handler

I'm not sure - any chance you could provide a case where this happens?

Imagine I click and drag the map by 5 pixels, initiating a "drag pan" gesture, put a rock on my mouse button, and go for lunch. Map#isMoving will be true the whole time I'm gone but the map won't be moving. Is that the behaviour we want? I'm not sure. It deserves some discussion.

[lucaswoj]

Using Map#flyTo in tests is tricky!

The default duration of Map#flyTo is rather long relative to our unit test execution time. In #2259 we sped up our unit tests from 19 seconds to 5 seconds by shortening the duration of a Map#flyTo test 😬

Perhaps the render event isn't getting fired as expected in our testing environment. Have you tried listening to move events instead?

[mapsam]

@lucaswoj just added map.easing as a property, which is enacted within map._easeTo and cancelled within map._easeEnd

Since zooming, rotating, and pitching are all within the ease functions, they're probably not 100% required any longer, but I haven't removed them just in case.

I also moved the map.dragRotate and map.dragPan checks to use their respective isActive() methods, rather than checking a private property.

Next up, tests!

[lucaswoj]

Let's define a "moving" map as a map whose center coordinate, bearing, zoom, or pitch is expected to be different in the next frame. Whether or not we "expect" these parameters to be different on the next frame during an interaction is an open question.

The word "easing" feels overloaded:

• the dictionary definition is to "move carefully, gradually, or gently"
• it can refer to the Map#easeTo operation
• it can refer to the internal Camera#_ease operation, used by both Map#easeTo and Map#flyTo

Let's think carefully about how we're using these words and how we can refactor to make their use more clear :-) #2801

---

To answer your original question:

wondering if instead of the map.easing property, can I just use map.isEasing()

Looks like this would work 👍

[mapsam]

Sure thing @lucaswoj. Since we already have the isEasing() method there's no need to start adding more properties/language like map.easing.

Since all of the potential "movements" have their own isSomething() methods except for zooming (i.e. there is no isZooming() method), it seems like we don't need to add anything else.

[mapsam]

@lucaswoj I've added a test that checks if the map is moving before, during, and after a flyTo animation. Let me know what you think!

[mapsam]

Closing this. I've got a better grasp on the camera movement, and think this can be better implemented once #3583 lands.