From a6c4927b27933fafc7a53ab00ef290173244cedb Mon Sep 17 00:00:00 2001
From: "P.Y. Laligand" <pylaligand@google.com>
Date: Wed, 17 Feb 2016 15:58:19 -0800
Subject: [PATCH] Added a few operators to the Velocity class.

#1968
---
 .../flutter/lib/src/gestures/velocity_tracker.dart     | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/packages/flutter/lib/src/gestures/velocity_tracker.dart b/packages/flutter/lib/src/gestures/velocity_tracker.dart
index 27fe9b4b32f..fe2ca138889 100644
--- a/packages/flutter/lib/src/gestures/velocity_tracker.dart
+++ b/packages/flutter/lib/src/gestures/velocity_tracker.dart
@@ -218,6 +218,16 @@ class Velocity {
   /// The number of pixels per second of velocity in the x and y directions.
   final Offset pixelsPerSecond;
 
+  Velocity operator -() => new Velocity(pixelsPerSecond: -pixelsPerSecond);
+  Velocity operator -(Velocity other) {
+    return new Velocity(
+        pixelsPerSecond: pixelsPerSecond - other.pixelsPerSecond);
+  }
+  Velocity operator +(Velocity other) {
+    return new Velocity(
+        pixelsPerSecond: pixelsPerSecond + other.pixelsPerSecond);
+  }
+
   bool operator ==(dynamic other) {
     if (other is! Velocity)
       return false;