[android] map snapshotter

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

@@ -0,0 +1,259 @@
+package com.mapbox.mapboxsdk.snapshotter;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.Canvas;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.annotation.UiThread;
+
+import com.mapbox.mapboxsdk.R;
+import com.mapbox.mapboxsdk.camera.CameraPosition;
+import com.mapbox.mapboxsdk.constants.Style;
+import com.mapbox.mapboxsdk.geometry.LatLngBounds;
+import com.mapbox.mapboxsdk.maps.MapboxMap;
+import com.mapbox.mapboxsdk.storage.FileSource;
+
+/**
+ * The map snapshotter creates a bitmap of the map, rendered
+ * off the UI thread. The snapshotter itself must be used on
+ * the UI thread (for access to the main looper)
+ */
+@UiThread
+public class MapSnapshotter {
+
+  /**
+   * Can be used to get notified of errors
+   * in snapshot generation
+   *
+   * @see MapSnapshotter#start(MapboxMap.SnapshotReadyCallback, ErrorHandler)
+   */
+  public static interface ErrorHandler {
+
+    /**
+     * Called on error. Snapshotting will not
+     * continue
+     *
+     * @param error the error message
+     */
+    void onError(String error);
+  }
+
+  private static final int LOGO_MARGIN_PX = 4;
+
+  // Holds the pointer to JNI NativeMapView
+  private long nativePtr = 0;
+
+  private final Context context;
+  private MapboxMap.SnapshotReadyCallback callback;
+  private ErrorHandler errorHandler;
+
+  /**
+   * MapSnapshotter options
+   */
+  public static class Options {
+    private int pixelRatio = 1;
+    private int width;
+    private int height;
+    private String styleUrl = Style.MAPBOX_STREETS;
+    private LatLngBounds region;
+    private CameraPosition cameraPosition;
+
+    /**
+     * @param width  the width of the image
+     * @param height the height of the image
+     */
+    public Options(int width, int height) {
+      this.width = width;
+      this.height = height;
+    }
+
+    /**
+     * @param url The style URL to use
+     * @return the mutated {@link Options}
+     */
+    public Options withStyle(String url) {
+      this.styleUrl = url;
+      return this;
+    }
+
+    /**
+     * @param region the region to show in the snapshot.
+     *               This is applied after the camera position
+     * @return the mutated {@link Options}
+     */
+    public Options withRegion(LatLngBounds region) {
+      this.region = region;
+      return this;
+    }
+
+    /**
+     * @param pixelRatio the pixel ratio to use (default: 1)
+     * @return the mutated {@link Options}
+     */
+    public Options withPixelRatio(int pixelRatio) {
+      this.pixelRatio = pixelRatio;
+      return this;
+    }
+
+    /**
+     * @param cameraPosition The camera position to use,
+     *                       the {@link CameraPosition#target} is overridden
+     *                       by region if set in conjunction.
+     * @return the mutated {@link Options}
+     */
+    public Options withCameraPosition(CameraPosition cameraPosition) {
+      this.cameraPosition = cameraPosition;
+      return this;
+    }
+
+    /**
+     * @return the width of the image
+     */
+    public int getWidth() {
+      return width;
+    }
+
+    /**
+     * @return the height of the image
+     */
+    public int getHeight() {
+      return height;
+    }
+
+    /**
+     * @return the pixel ratio
+     */
+    public int getPixelRatio() {
+      return pixelRatio;
+    }
+
+    /**
+     * @return the region
+     */
+    @Nullable
+    public LatLngBounds getRegion() {
+      return region;
+    }
+
+    /**
+     * @return the style url
+     */
+    public String getStyleUrl() {
+      return styleUrl;
+    }
+
+    /**
+     * @return the camera position
+     */
+    @Nullable
+    public CameraPosition getCameraPosition() {
+      return cameraPosition;
+    }
+  }
+
+  /**
+   * Creates the Map snapshotter, but doesn't start rendering or
+   * loading yet.
+   *
+   * @param context the Context that is or contains the Application context
+   * @param options the options to use for the snapshot
+   */
+  public MapSnapshotter(@NonNull Context context, @NonNull Options options) {
+    this.context = context.getApplicationContext();
+    FileSource fileSource = FileSource.getInstance(context);
+    String programCacheDir = context.getCacheDir().getAbsolutePath();
+
+    nativeInitialize(this, fileSource, options.pixelRatio, options.width,
+      options.height, options.styleUrl, options.region, options.cameraPosition,
+      programCacheDir);
+  }
+
+  /**
+   * Starts loading and rendering the snapshot. The callback will be fired
+   * on the calling thread.
+   *
+   * @param callback the callback to use when the snapshot is ready
+   */
+  public void start(@NonNull MapboxMap.SnapshotReadyCallback callback) {
+    this.start(callback, null);
+  }
+
+  /**
+   * Starts loading and rendering the snapshot. The callbacks will be fired
+   * on the calling thread.
+   *
+   * @param callback the callback to use when the snapshot is ready
+   * @param errorHandler the error handler to use on snapshot errors
+   */
+  public void start(@NonNull MapboxMap.SnapshotReadyCallback callback, ErrorHandler errorHandler) {
+    if (this.callback != null) {
+      throw new IllegalStateException("Snapshotter was already started");
+    }
+
+    this.callback = callback;
+    nativeStart();
+  }
+
+  /**
+   * Must be called in on the thread
+   * the object was created on.
+   */
+  public void cancel() {
+    callback = null;
+    nativeCancel();
+  }
+
+  protected void addOverlay(Bitmap original) {
+    float margin = context.getResources().getDisplayMetrics().density * LOGO_MARGIN_PX;
+    Canvas canvas = new Canvas(original);
+    Bitmap logo = BitmapFactory.decodeResource(context.getResources(), R.drawable.mapbox_logo_icon, null);
+    canvas.drawBitmap(logo, margin, original.getHeight() - (logo.getHeight() + margin), null);
+  }
+
+  /**
+   * Called by JNI peer when snapshot is ready.
+   * Always called on the origin (main) thread.
+   *
+   * @param bitmap the generated snapshot
+   */
+  protected void onSnapshotReady(Bitmap bitmap) {
+    if (callback != null) {
+      addOverlay(bitmap);
+      callback.onSnapshotReady(bitmap);
+      reset();
+    }
+  }
+
+  /**
+   * Called by JNI peer when snapshot has failed.
+   * Always called on the origin (main) thread.
+   *
+   * @param reason the exception string
+   */
+  protected void onSnapshotFailed(String reason) {
+    if (errorHandler != null) {
+      errorHandler.onError(reason);
+      reset();
+    }
+  }
+
+  protected void reset() {
+    callback = null;
+    errorHandler = null;
+  }
+
+  protected native void nativeInitialize(MapSnapshotter mapSnapshotter,
+                                         FileSource fileSource, float pixelRatio,
+                                         int width, int height, String styleUrl,
+                                         LatLngBounds region, CameraPosition position,
+                                         String programCacheDir);
+
+  protected native void nativeStart();
+
+  protected native void nativeCancel();
+
+  @Override
+  protected native void finalize() throws Throwable;
+}