feat(render): add camera scale adjustment on window resize

Implement a new system to adjust the camera scale when the window is resized, ensuring
the board always fits within the viewport. The `adjust_camera_scale` function calculates
the appropriate scale based on the window size and the board dimensions, maintaining
a consistent zoom level.

src/main.rs

@@ -6,20 +6,19 @@ mod components;
 mod database;
 mod events;
 mod input_map;
-mod utils;
 mod plugins;
 mod resources;
 mod solve;
 mod state;
 mod systems;
 mod test;
+mod utils;
 
 use bevy::prelude::*;
 use bevy_kira_audio::prelude::*;
 use events::*;
 use input_map::*;
 use leafwing_input_manager::prelude::*;
-use utils::*;
 use plugins::performance_matrix::*;
 use resources::*;
 use state::*;
@@ -32,6 +31,7 @@ use systems::input::*;
 use systems::level::*;
 use systems::render::*;
 use systems::ui::*;
+use utils::*;
 
 const CONFIG_FILE_PATH: &str = "config.toml";
 
@@ -97,6 +97,7 @@ fn main() {
             update_button_state,
             handle_audio_event,
             adjust_viewport,
+            adjust_camera_scale,
             save_config.run_if(resource_changed_or_removed::<Config>()),
             (button_input_to_action, handle_actions).chain(),
         ),

src/resources.rs

@@ -5,8 +5,8 @@ use serde::{Deserialize, Serialize};
 use soukoban::{Level, Map};
 
 use crate::database;
-use crate::utils::PushState;
 use crate::solve::solver::*;
+use crate::utils::PushState;
 use soukoban::direction::Direction;
 
 use std::collections::{HashMap, VecDeque};

src/systems/input.rs

@@ -9,10 +9,10 @@ use nalgebra::Vector2;
 use soukoban::{Level, Tiles};
 
 use crate::events::*;
-use crate::utils::PushState;
 use crate::resources::*;
 use crate::solve::solver::*;
 use crate::systems::level::*;
+use crate::utils::PushState;
 use crate::AppState;
 use crate::{components::*, Action};
 use soukoban::direction::Direction;

src/systems/level.rs

@@ -5,6 +5,7 @@ use soukoban::Level;
 use soukoban::Tiles;
 
 use crate::board;
+use crate::calculate_camera_default_scale;
 use crate::components::*;
 use crate::database;
 use crate::resources::*;
@@ -80,15 +81,7 @@ pub fn spawn_board(
     transform.translation.x = (board_size.x - tile_size.x) / 2.0;
     transform.translation.y = (board_size.y + tile_size.y) / 2.0;
 
-    let window = window.single();
-    let width_scale = board_size.x / window.resolution.width();
-    let height_scale = board_size.y / window.resolution.height();
-    let scale = if width_scale > height_scale {
-        width_scale
-    } else {
-        height_scale
-    };
-    main_camera.target_scale = scale / 0.9;
+    main_camera.target_scale = calculate_camera_default_scale(window.single(), &level);
 
     // despawn the previous `Board`
     commands.entity(board.single()).despawn_recursive();

src/systems/render.rs

@@ -1,12 +1,14 @@
 use benimator::{Animation, FrameRate};
 use bevy::prelude::*;
+use bevy::window::WindowResized;
 use bevy::winit::WinitWindows;
 use nalgebra::Vector2;
+use soukoban::direction::Direction;
+use soukoban::Level;
 
 use crate::components::*;
 use crate::events::*;
 use crate::resources::*;
-use soukoban::direction::Direction;
 
 use std::cmp::Ordering;
 use std::collections::HashSet;
@@ -249,3 +251,33 @@ pub fn update_grid_position_from_board(
         }
     }
 }
+
+pub fn adjust_camera_scale(
+    mut camera: Query<&mut MainCamera>,
+    window: Query<&Window>,
+    board: Query<&Board>,
+    mut events: EventReader<WindowResized>,
+) {
+    if events.is_empty() {
+        return;
+    }
+    events.clear();
+
+    camera.single_mut().target_scale =
+        calculate_camera_default_scale(window.single(), &board.single().board.level);
+}
+
+/// Adjust the camera zoom to fit the entire board.
+pub fn calculate_camera_default_scale(window: &Window, level: &Level) -> f32 {
+    let tile_size = Vector2::new(128.0, 128.0);
+    let board_size = tile_size.x * level.dimensions().map(|x| x as f32);
+
+    let width_scale = board_size.x / window.resolution.width();
+    let height_scale = board_size.y / window.resolution.height();
+    let scale = if width_scale > height_scale {
+        width_scale
+    } else {
+        height_scale
+    };
+    scale / 0.9
+}