Add visualization image output

factorio-core/src/visualize/mod.rs

@@ -14,13 +14,19 @@ pub trait Visualize {
         print::print(v);
     }
 
-    fn png_visualization(&self, file: impl AsRef<std::path::Path>) {
+    fn image_visualization(&self) -> RgbaImage {
         let v = self.visualize();
 
         let mut img = RgbaImage::new((v.size.x * 10) as u32, (v.size.y * 10) as u32);
 
         image::draw(&v, &mut img);
 
+        img
+    }
+
+    fn png_visualization(&self, file: impl AsRef<std::path::Path>) {
+        let img = self.image_visualization();
+
         let mut f = std::fs::File::create(file).unwrap();
         let _ = img.write_to(&mut f, ::image::ImageFormat::Png);
     }