Generalize rendering into a trait

src/render.rs

@@ -7,8 +7,12 @@ use y4m::{Colorspace, encode, Encoder, Frame, Ratio};
 
 pub struct NumericTermRenderer;
 
-impl NumericTermRenderer {
-    pub fn render(&self, state: &SimState) {
+pub trait Renderer {
+    fn render(&mut self, state: &SimState);
+}
+
+impl Renderer for NumericTermRenderer {
+    fn render(&mut self, state: &SimState) {
         for y in 0..state.height() {
             for x in 0..state.width() {
                 let cell = state.get(x, y);
@@ -44,8 +48,8 @@ fn curl(x: f64, y: f64) -> f64 {
     }
 }
 
-impl ColorTermRenderer {
-    pub fn render(&self, state: &SimState) {
+impl Renderer for ColorTermRenderer {
+    fn render(&mut self, state: &SimState) {
         let mut buf = String::new();
         let square = "█";
         for y in 0..state.height() {
@@ -82,7 +86,10 @@ impl Y4MRenderer {
             encoder: None,
         }
     }
-    pub fn render(&mut self, state: &SimState) {
+}
+
+impl Renderer for Y4MRenderer {
+    fn render(&mut self, state: &SimState) {
         if self.encoder.is_none() {
             let writer = File::create(&self.out_path).unwrap();
             self.encoder = Some(encode(state.width(), state.height(), Ratio::new(30, 1))