From a03757e443de97c8a08174a1d50bc0186244cde6 Mon Sep 17 00:00:00 2001
From: Hixie <github.com@spam.hixie.ch>
Date: Wed, 25 Nov 2015 17:15:00 -0800
Subject: [PATCH] Operators needed to lerp a FractionalOffset.

Without this, you can't use AnimatedValue<FractionalOffset>, because its
lerp() function uses the operators.
---
 packages/flutter/lib/src/painting/box_painter.dart | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/packages/flutter/lib/src/painting/box_painter.dart b/packages/flutter/lib/src/painting/box_painter.dart
index 89887aa93a1..8fce9012e04 100644
--- a/packages/flutter/lib/src/painting/box_painter.dart
+++ b/packages/flutter/lib/src/painting/box_painter.dart
@@ -1110,6 +1110,15 @@ class FractionalOffset {
   const FractionalOffset(this.x, this.y);
   final double x;
   final double y;
+  FractionalOffset operator -(FractionalOffset other) {
+    return new FractionalOffset(x - other.x, y - other.y);
+  }
+  FractionalOffset operator +(FractionalOffset other) {
+    return new FractionalOffset(x + other.x, y + other.y);
+  }
+  FractionalOffset operator *(double other) {
+    return new FractionalOffset(x * other, y * other);
+  }
   bool operator ==(dynamic other) {
     if (other is! FractionalOffset)
       return false;