Android beta 6 : LatLngBounds.Builder()

[Etienne-io]

Platform: Android
Mapbox SDK version: 6.0.0-beta.6

Steps to trigger behaviour

1. Create Polygon that is a Rectangle
2. Add each coordinate of this Polygon using LatLngBounds.Builder().include(latLng)
3. Display a line from south west to north east

Expected behavior

The line should be a diagonale of the original rectangle.

Actual behavior

The line seems to be the left edge of the original rectangle

Exemple :

Original polygon :

Computed bounds :

Note : I have no issue with non-rectangle polygon

It works on Android 5.5.0. The problem seems to come from : e4a40fe#diff-24a1903a5def25e6a975df6b3ea38b40

[tobrun]

cc @osana

[osana]

Here is a code snippet that I tried and it works as expected:

    LatLngBounds visibleBounds = mapboxMap.getProjection().getVisibleRegion().latLngBounds;
    LatLng northEast = visibleBounds.getNorthEast();
    LatLng southWest = visibleBounds.getSouthWest();

    final double delta = 0.01;

    LatLngBounds newBounds =
      new LatLngBounds.Builder()
        .include(new LatLng(northEast.getLatitude() - delta,
          northEast.getLongitude() - delta))
        .include(new LatLng(southWest.getLatitude() + delta,
          southWest.getLongitude() + delta))
        .build();

    // add rectangle to a map
    PolygonOptions boundsArea = new PolygonOptions()
      .add(newBounds.getNorthWest())
      .add(newBounds.getNorthEast())
      .add(newBounds.getSouthEast())
      .add(newBounds.getSouthWest());
    boundsArea.alpha(0.25f);
    boundsArea.fillColor(Color.RED);
    mapboxMap.addPolygon(boundsArea);
    
    // draw rectangle's diagonal
    PolylineOptions diagonal = new PolylineOptions()
      .add(newBounds.getNorthEast())
      .add(newBounds.getSouthWest());
    diagonal.color(Color.BLUE);
    diagonal.width(4);
    mapboxMap.addPolyline(diagonal);

I tried rotating the map and doing and diagonal was drawn from northEast to souWest corners.

Could you provide us with a code snippet of what is not working. Thank you.

cc @tobrun

[Etienne-io]

You can try this code :

PolygonOptions opts = new PolygonOptions()
                        .add(new LatLng(50.63018102643986, 3.0535175809382062))
                        .add(new LatLng(50.63073906475279, 3.0535175809382062))
                        .add(new LatLng(50.63073906475279, 3.054754028380558))
                        .add(new LatLng(50.63018102643986, 3.054754028380558))
                        .add(new LatLng(50.63018102643986, 3.0535175809382062))
                        .fillColor(Color.GREEN)
                        .alpha(0.4f);
                mapboxMap.addPolygon(opts);

                LatLngBounds llb = new LatLngBounds.Builder()
                        .include(new LatLng(50.63018102643986, 3.0535175809382062))
                        .include(new LatLng(50.63073906475279, 3.0535175809382062))
                        .include(new LatLng(50.63073906475279, 3.054754028380558))
                        .include(new LatLng(50.63018102643986, 3.054754028380558))
                        .include(new LatLng(50.63018102643986, 3.0535175809382062))
                        .build();
                PolylineOptions plopts = new PolylineOptions()
                        .add(llb.getSouthWest())
                        .add(llb.getNorthEast())
                        .color(Color.RED);
                mapboxMap.addPolyline(plopts);

                mapboxMap.setCameraPosition(new CameraPosition.Builder().target(new LatLng(50.63018102643986, 3.0535175809382062)).zoom(18).build());

If you want funny behaviour, replace the last line with :

mapboxMap.setCameraPosition(new CameraPosition.Builder().target(llb.getCenter()).build());

[osana]

The bug is when the first two points have the same longitude.

Fails when points are passed to the Builder in the order like:
sw, nw, ne, se
nw, sw, ne, se
ne, se, sw, nw
se, ne, sw, nw

I will add unit tests with first two points having the same longitude and another test with first two points having the same latitude.

cc @tobrun