coordinateForPoint inaccurate for Android.

[jamiesonbates]

Is this a bug report?

Yes.

Have you read the Installation Instructions?

Yes.

Environment

react-native: 0.55.3
react: 16.3.1
react-native-maps: "git+https://github.com/react-community/react-native-maps.git"

Steps to Reproduce

1. Navigate to a view with a map on it.
2. Make sure you are in a mode that allows you to draw on the map by pressing and holding your finger on your device.
3. Press and hold, while drawing a circle or other shape.
4. Release.

Expected Behavior

The circle generated should generate a list of x/y points in relation to the screen, and then run each through the function coordinateForPoint attached to the map ref. These points will then generate a polyline that resemble exactly where on the map the circle was drawn with your finger.

Then, the coordinateForPoint function should reliable cast a Point as a Coordinate.

Actual Behavior

On android only, this does not work. Instead, the polyline is cast on a different part of the screen (lower and to the right). I think this is a bug with coordinateForPoint because it should be comparing reliably to the mapview visible on the screen, but seems to be casting on a larger view (off-screen).

Unfortunately, I cannot give screenshots, but I created an expo example.

Reproducible Demo

I have built a working example to explain how it is supposed to work. However, I don't think expo has the most recent react-native-maps version and "coordinateForPoint" does not seem to exist when testing on Android.

When testing on IOS it displays what should (mostly) happen. The circle is a polyline drawn from coordinates generated through coordinateForPoint (I am not sure why the red line connects all of them, but its irrelevant for arguments sake).

https://snack.expo.io/@jamiesonbates/react-native-maps-coordinateforpoint-example

[danielgindi]

There's already a PR for that (#2390)
A temporary workaround:

    let position = await this._refs.map.pointForCoordinate(coordinate);
    if (Platform.OS === 'android') { // FIXME: Remove this in next module version
      position.x = position.x / PixelRatio.get();
      position.y = position.y / PixelRatio.get();
    }

[jamiesonbates]

@danielgindi thank you so much for the work around. Saved me a ton of time. Looking forward to the PR.

Appreciate your contribution to this library as well.

[jamiesonbates]

Duplicate of #2390

[cklinx]

There's already a PR for that (#2390)
A temporary workaround:

    let position = await this._refs.map.pointForCoordinate(coordinate);
    if (Platform.OS === 'android') { // FIXME: Remove this in next module version
      position.x = position.x / PixelRatio.get();
      position.y = position.y / PixelRatio.get();
    }

@danielgindi Thanks man, you saved my life!

[danielgindi]

@cklinx This is actually old, and the "next" module version is here. If you upgrade, you do not need this workaround :-)