Dynamic UI resolution

assets/martian.tweak.toml

@@ -29,6 +29,10 @@ Space Blanket Folds - https://www.textures.com/download/PBR0152/133187
 Background 2D art by NASA: LINK HERE
 """
 
+[resolution]
+x = 640
+y = 480
+
 #########################################################################
 # Audio settings
 #########################################################################

src/main.rs

@@ -49,7 +49,6 @@ fn main() {
             .set(WindowPlugin {
                 primary_window: Some(Window {
                     title: "Martian Chess".into(),
-                    resolution: (1280.0, 720.0).into(),
                     ..default()
                 }),
                 ..default()

src/ui.rs

@@ -11,6 +11,10 @@ impl Plugin for UiPlugin {
             (
                 manage_cursor.run_if(any_component_changed::<Interaction>),
                 interactive_button.run_if(any_component_changed::<Interaction>),
+                scale_ui
+                    .run_if(any_component_changed::<Window>)
+                    .run_if(resource_exists::<tweak::GameTweaks>()),
+                scale_ui.run_if(on_event::<AssetEvent<tweak::Tweaks>>()),
             ),
         );
     }
@@ -61,3 +65,38 @@ fn interactive_button(
             }
         });
 }
+
+
+fn scale_ui(
+    mut windows: Query<&mut Window, Changed<Window>>,
+    mut ui_scale: ResMut<UiScale>,
+    mut resolution_set: Local<bool>,
+    tweakfile: Res<tweak::GameTweaks>,
+    tweaks: Res<Assets<tweak::Tweaks>>,
+) {
+    // There is only 1 window
+    assert_eq!(windows.iter().count(), 1);
+
+    if !tweaks.contains(tweakfile.handle.clone()) {
+        return
+    }
+    let tweak = tweaks.get(tweakfile.handle.clone()).unwrap();
+    let width = tweak.get::<f32>("resolution_x").unwrap();
+    let height = tweak.get::<f32>("resolution_y").unwrap();
+
+    windows.iter_mut().for_each(|mut w| {
+        // Setting window resolution at startup
+        if !*resolution_set {
+            w.resolution.set(width, height);
+            *resolution_set = true;
+        }
+
+        // Setting UI Scale based on ratio of expected to current ratio
+        let width_ratio = w.resolution.width() / width;
+        let height_ratio = w.resolution.height() / height; 
+        let new_scale = (width_ratio).min(height_ratio) as f64;
+        if ui_scale.0 != new_scale {
+            ui_scale.0 = new_scale;
+        }
+    });
+}