fix selfie horizontal flip

Closes #4635
// FREEBIE

src/org/thoughtcrime/securesms/components/camera/CameraView.java

@@ -541,7 +541,8 @@ public class CameraView extends FrameLayout {
                                          previewSize.width,
                                          previewSize.height,
                                          rotation,
-                                         croppingRect);
+                                         croppingRect,
+                                         cameraId == CameraInfo.CAMERA_FACING_FRONT);
       } catch (IOException e) {
         Log.w(TAG, e);
         return null;

src/org/thoughtcrime/securesms/util/BitmapUtil.java

@@ -157,10 +157,11 @@ public class BitmapUtil {
                                       final int width,
                                       final int height,
                                       int rotation,
-                                      final Rect croppingRect)
+                                      final Rect croppingRect,
+                                      final boolean flipHorizontal)
       throws IOException
   {
-    byte[] rotated = rotateNV21(data, width, height, rotation);
+    byte[] rotated = rotateNV21(data, width, height, rotation, flipHorizontal);
     final int rotatedWidth  = rotation % 180 > 0 ? height : width;
     final int rotatedHeight = rotation % 180 > 0 ? width  : height;
     YuvImage previewImage = new YuvImage(rotated, ImageFormat.NV21,
@@ -183,7 +184,8 @@ public class BitmapUtil {
   public static byte[] rotateNV21(@NonNull final byte[] yuv,
                                   final int width,
                                   final int height,
-                                  final int rotation)
+                                  final int rotation,
+                                  final boolean flipHorizontal)
       throws IOException
   {
     if (rotation == 0) return yuv;
@@ -196,7 +198,7 @@ public class BitmapUtil {
     final byte[]  output    = new byte[yuv.length];
     final int     frameSize = width * height;
     final boolean swap      = rotation % 180 != 0;
-    final boolean xflip     = rotation % 270 != 0;
+    final boolean xflip     = flipHorizontal ? rotation % 270 == 0 : rotation % 270 != 0;
     final boolean yflip     = rotation >= 180;
 
     for (int j = 0; j < height; j++) {