Support convert from UpperLeft, Center in BoundingBoxUtils

tensorflow/lite/experimental/support/java/src/java/org/tensorflow/lite/support/image/BoundingBoxUtil.java

@@ -180,9 +180,9 @@ private static RectF convertOneBoundingBox(
       case BOUNDARIES:
         return convertFromBoundaries(values, coordinateType, height, width);
       case UPPER_LEFT:
+        return convertFromUpperLeft(values, coordinateType, height, width);
       case CENTER:
-        // TODO(b/150824448): convertFrom{UpperLeft, Center}
-        throw new IllegalArgumentException("BoundingBox.Type " + type + " is not yet supported.");
+        return convertFromCenter(values, coordinateType, height, width);
     }
     throw new IllegalArgumentException("Cannot recognize BoundingBox.Type " + type);
   }
@@ -197,6 +197,42 @@ private static RectF convertFromBoundaries(
     }
   }
 
+  private static RectF convertFromUpperLeft(
+      float[] values, CoordinateType coordinateType, int height, int width) {
+    if (coordinateType == CoordinateType.PIXEL) {
+      float left = values[0];
+      float top = values[1];
+      float w = values[2];
+      float h = values[3];
+
+      return new RectF(
+        left, top, left+w, top+h);
+    } else {
+      return new RectF(
+        values[0] * width, values[1] * height, (float) width, (float) height);
+    }
+  }
+
+  private static RectF convertFromCenter(
+      float[] values, CoordinateType coordinateType, int height, int width) {
+    if (coordinateType == CoordinateType.PIXEL) {
+      float centerX = values[0];
+      float centerY = values[1];
+      float w = values[2];
+      float h = values[3];
+
+      float left = centerX - w/2;
+      float top = centerY - h/2;
+      float right = centerX + w/2;
+      float bottom = centerX + h/2;
+
+      return new RectF(
+        left, top, right, bottom);
+    } else {
+      throw new IllegalArgumentException("BoundingBox.Type Center is not supported with CoordinateType CoordinateType.RATIO");
+    }
+  }
+
   // Private constructor to prevent initialization.
   private BoundingBoxUtil() {}
 }