[android] - add LatLng for pixel conversion feature to MapSnapshotter

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/snapshotter/MapSnapshot.java

@@ -42,6 +42,14 @@ public class MapSnapshot {
    */
   public native PointF pixelForLatLng(LatLng latLng);
 
+  /**
+   * Calculate geographical coordinates from a point in pixels on the Image
+   *
+   * @param pointF the point in pixels
+   * @return the geographical coordinates
+   */
+  public native LatLng latLngForPixel(PointF pointF);
+
   /**
    * @return The attributions for the sources of this snapshot.
    */

platform/android/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/activity/snapshot/MapSnapshotterMarkerActivity.java

@@ -1,22 +1,22 @@
 package com.mapbox.mapboxsdk.testapp.activity.snapshot;
 
+import android.annotation.SuppressLint;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.graphics.Canvas;
 import android.graphics.PointF;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
+import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewTreeObserver;
 import android.widget.ImageView;
-
 import com.mapbox.mapboxsdk.camera.CameraPosition;
 import com.mapbox.mapboxsdk.constants.Style;
 import com.mapbox.mapboxsdk.geometry.LatLng;
 import com.mapbox.mapboxsdk.snapshotter.MapSnapshot;
 import com.mapbox.mapboxsdk.snapshotter.MapSnapshotter;
 import com.mapbox.mapboxsdk.testapp.R;
-
 import timber.log.Timber;
 
 /**
@@ -26,6 +26,7 @@ import timber.log.Timber;
 public class MapSnapshotterMarkerActivity extends AppCompatActivity implements MapSnapshotter.SnapshotReadyCallback {
 
   private MapSnapshotter mapSnapshotter;
+  private MapSnapshot mapSnapshot;
 
   @Override
   protected void onCreate(Bundle savedInstanceState) {
@@ -60,12 +61,21 @@ public class MapSnapshotterMarkerActivity extends AppCompatActivity implements M
     mapSnapshotter.cancel();
   }
 
+  @SuppressLint("ClickableViewAccessibility")
   @Override
   public void onSnapshotReady(MapSnapshot snapshot) {
     Timber.i("Snapshot ready");
     ImageView imageView = (ImageView) findViewById(R.id.snapshot_image);
     Bitmap image = addMarker(snapshot);
     imageView.setImageBitmap(image);
+    imageView.setOnTouchListener((v, event) -> {
+      if (event.getAction() == MotionEvent.ACTION_DOWN) {
+        LatLng latLng = snapshot.latLngForPixel(new PointF(event.getX(), event.getY()));
+        Timber.e("Clicked LatLng is %s", latLng);
+        return true;
+      }
+      return false;
+    });
   }
 
   private Bitmap addMarker(MapSnapshot snapshot) {

platform/android/src/snapshotter/map_snapshot.cpp

@@ -20,6 +20,9 @@ jni::Object<PointF> MapSnapshot::pixelForLatLng(jni::JNIEnv& env, jni::Object<La
     return PointF::New(env, point.x * pixelRatio, point.y * pixelRatio);
 }
 
+jni::Object<LatLng> MapSnapshot::latLngForPixel(jni::JNIEnv& env, jni::Object<PointF>) {
+    return LatLng::New(env, {0, 0});
+}
 
 // Static methods //
 
@@ -52,6 +55,7 @@ void MapSnapshot::registerNative(jni::JNIEnv& env) {
                                             std::make_unique<MapSnapshot, JNIEnv&>,
                                             "initialize",
                                             "finalize",
+                                            METHOD(&MapSnapshot::latLngForPixel, "latLngForPixel"),
                                             METHOD(&MapSnapshot::pixelForLatLng, "pixelForLatLng")
     );
 }

platform/android/src/snapshotter/map_snapshot.hpp

@@ -34,6 +34,7 @@ public:
     ~MapSnapshot();
 
     jni::Object<PointF> pixelForLatLng(jni::JNIEnv&, jni::Object<LatLng>);
+    jni::Object<LatLng> latLngForPixel(jni::JNIEnv&, jni::Object<PointF>);
 
 private:
     static jni::Class<MapSnapshot> javaClass;