[android] - limit the scale factor for double tap zoom (#7580)

* [android] - limit the scale factor to avoid accelerating the double tap zoom gesture

* clamp values

3 files changed, 17 insertions, 1 deletions

diff --git a/platform/android/CHANGELOG.md b/platform/android/CHANGELOG.md
index e176810277..97d8b931c8 100644
--- a/platform/android/CHANGELOG.md
+++ b/platform/android/CHANGELOG.md
@@ -4,6 +4,7 @@ Mapbox welcomes participation and contributions from everyone.  If you'd like to
 
 ## 5.0.0 - TBA
 
+* Consistent double tap zoom acceleration [#7514](https://github.com/mapbox/mapbox-gl-native/issues/7514)
 * Support for Android Nougat [#5910](5910-move-listener-logic-for-nougat) & [#6390](https://github.com/mapbox/mapbox-gl-native/pull/6390)
 
 ## 4.2.1 - December 22, 2016
diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/constants/MapboxConstants.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/constants/MapboxConstants.java
index e2a5d40795..689b596f98 100644
--- a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/constants/MapboxConstants.java
+++ b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/constants/MapboxConstants.java
@@ -83,6 +83,16 @@ public class MapboxConstants {
   public static final double MINIMUM_DIRECTION = 0;
 
   /**
+   * The currently used minimun scale factor to clamp to when a quick zoom gesture occurs
+   */
+  public static final float MINIMUM_SCALE_FACTOR_CLAMP = 0.65f;
+
+  /**
+   * The currently used maximum scale factor to clamp to when a quick zoom gesture occurs
+   */
+  public static final float MAXIMUM_SCALE_FACTOR_CLAMP = 1.35f;
+
+  /**
    * Fragment Argument Key for MapboxMapOptions
    */
   public static final String FRAG_ARG_MAPBOXMAPOPTIONS = "MapboxMapOptions";
diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapGestureDetector.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapGestureDetector.java
index 93422b1837..053aa72fdf 100644
--- a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapGestureDetector.java
+++ b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapGestureDetector.java
@@ -16,6 +16,7 @@ import com.almeros.android.multitouch.gesturedetectors.ShoveGestureDetector;
 import com.almeros.android.multitouch.gesturedetectors.TwoFingerGestureDetector;
 import com.mapbox.mapboxsdk.constants.MapboxConstants;
 import com.mapbox.mapboxsdk.telemetry.MapboxEvent;
+import com.mapbox.mapboxsdk.utils.MathUtils;
 
 /**
  * Manages gestures events on a MapView.
@@ -427,8 +428,12 @@ final class MapGestureDetector {
         // arround user provided focal point
         transform.zoomBy(detector.getScaleFactor(), focalPoint.x, focalPoint.y);
       } else if (quickZoom) {
+        // clamp scale factors we feed to core #7514
+        float scaleFactor = MathUtils.clamp(detector.getScaleFactor(),
+          MapboxConstants.MINIMUM_SCALE_FACTOR_CLAMP,
+          MapboxConstants.MAXIMUM_SCALE_FACTOR_CLAMP);
         // around center map
-        transform.zoomBy(detector.getScaleFactor(), uiSettings.getWidth() / 2, uiSettings.getHeight() / 2);
+        transform.zoomBy(scaleFactor, uiSettings.getWidth() / 2, uiSettings.getHeight() / 2);
       } else {
         // around gesture
         transform.zoomBy(detector.getScaleFactor(), detector.getFocusX(), detector.getFocusY());