Example with ownership

You can't trick the borrow checker, by putting references into another struct

src/main.rs

@@ -1,4 +1,4 @@
-#[derive(Copy, Clone)]
+//#[derive(Copy, Clone)]
 struct RGB {
     red: u8,
     green: u8,
@@ -11,19 +11,11 @@ impl RGB {
     }
 
     fn black() -> RGB {
-        RGB {
+        RGB::new(0, 0, 0)
-            red: 0,
-            green: 0,
-            blue: 0,
-        }
     }
 
     fn white() -> RGB {
-        RGB {
+        RGB::new(255, 255, 255)
-            red: 255,
-            green: 255,
-            blue: 255,
-        }
     }
 }
 
@@ -58,13 +50,42 @@ impl Image {
         Image::new(width, height, data)
     }
 
-    fn get(&self, x: usize, y: usize) -> RGB {
+    fn get(&self, x: usize, y: usize) -> &RGB {
-        self.data[y * self.width + x]
+        self.data.get(y * self.width + x).unwrap()
+    }
+
+    fn get_mut(&mut self, x: usize, y: usize) -> &mut RGB {
+        self.data.get_mut(y * self.width + x).unwrap()
+    }
+}
+
+struct Container<'a> {
+    value: &'a RGB,
+}
+
+impl<'a> Container<'a> {
+    fn new(value: &RGB) -> Container {
+        Container { value }
+    }
+}
+
+fn brighter<'a>(a: &'a RGB, b: &'a RGB) -> &'a RGB {
+    if a.red / 3 + a.green / 3 + a.blue / 3 > b.red / 3 + b.green / 3 + b.blue / 3 {
+        a
+    } else {
+        b
     }
 }
 
 fn main() {
     let image = Image::white_image(640, 480);
 
-    let c = image.get(0, 0);
+    let black = RGB::black();
+
+    let c1 = image.get(0, 0);
+    //let c2 = image.get(1, 1);
+
+    let brightest = brighter(c1, &black);
+
+    println!("{}", brightest.red);
 }