1 files changed, 57 insertions, 0 deletions
diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/widgets/scaleview/MapScaleModel.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/widgets/scaleview/MapScaleModel.java
new file mode 100644
index 0000000000..2245d1d40a
--- /dev/null
+++ b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/widgets/scaleview/MapScaleModel.java
@@ -0,0 +1,57 @@
+package com.mapbox.mapboxsdk.maps.widgets.scaleview;
+
+import android.graphics.PointF;
+
+import com.mapbox.mapboxsdk.camera.CameraPosition;
+import com.mapbox.mapboxsdk.geometry.LatLng;
+import com.mapbox.mapboxsdk.maps.Projection;
+
+
+class MapScaleModel {
+
+    private final int[] meters = {
+            150,350,700, 1500, 2500, 5000, 10000, 20000, 40000, 100000, 150000, 350000, 700000, 1500000, 2500000};
+
+    private final LatLng src = new LatLng(31, 121);
+
+    private int maxWidth;
+
+    private double zoom = -1;
+    private Scale scale;
+
+    MapScaleModel() {
+    }
+
+    void setMaxWidth(int width) {
+        maxWidth = width;
+    }
+
+    Scale setProjection(Projection projection, CameraPosition cameraPosition) {
+        if (zoom == cameraPosition.zoom) return scale;
+
+        int distance = 0;
+        int distanceIndex = meters.length;
+        double screenDistance = maxWidth + 1;
+
+        while (screenDistance > maxWidth && distanceIndex > 0) {
+            distance = meters[--distanceIndex];
+
+            LatLng dest = DistanceUtils.translatePoint(src, distance, 120);
+
+            PointF pointSrc = projection.toScreenLocation(src);
+            PointF pointDest = projection.toScreenLocation(dest);
+
+            screenDistance = Math.sqrt(Math.pow(pointSrc.x - pointDest.x, 2) + Math.pow(pointSrc.y - pointDest.y, 2));
+        }
+
+        zoom = cameraPosition.zoom;
+        scale = new Scale(text(distance), (float) screenDistance);
+
+        return scale;
+    }
+
+    private String text(int distance) {
+        if (distance < 1000) return distance + " m";
+        else return distance / 1000 + " km";
+    }
+}