From 3ce85fcb5eda8fcb871bdc20552e06dcb652313d Mon Sep 17 00:00:00 2001
From: Max Bradbury <max@tinybird.info>
Date: Mon, 20 Jul 2020 21:05:25 +0100
Subject: [PATCH] Image.invert()

---
 src/image.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/image.rs b/src/image.rs
index 3090a69..c9679e7 100644
--- a/src/image.rs
+++ b/src/image.rs
@@ -4,6 +4,10 @@ pub struct Image {
 }
 
 impl Image {
+    pub fn invert(&mut self) {
+        self.pixels = self.pixels.iter().map(|pixel| 1 - pixel).collect();
+    }
+
     /// flip image vertically
     pub fn flip(&mut self) {
         let mut pixels = Vec::with_capacity(64);
@@ -159,6 +163,14 @@ mod test {
         assert_eq!(output, expected);
     }
 
+    #[test]
+    fn invert() {
+        let mut output = crate::mock::image::chequers_1();
+        output.invert();
+        let expected = crate::mock::image::chequers_2();
+        assert_eq!(output, expected);
+    }
+
     #[test]
     fn flip() {
         let mut image = crate::mock::image::asymmetrical();