Remove unused function inputs

crates/fj-viewer/src/input/handler.rs

@@ -1,5 +1,3 @@
-use std::time::Instant;
-
 use fj_interop::mesh::Mesh;
 use fj_math::Point;
 
@@ -24,24 +22,6 @@ pub struct Handler {
 }
 
 impl Handler {
-    /// Returns a new Handler.
-    ///
-    /// # Examples
-    /// ```rust no_run
-    /// // Store initialization time for camera zoom calculations
-    /// let instant = std::time::Instant::now();
-    /// let input_handler = fj_viewer::input::Handler::new(instant);
-    /// ```
-    pub fn new(now: Instant) -> Self {
-        Self {
-            cursor: None,
-
-            movement: Movement::new(),
-            rotation: Rotation::new(),
-            zoom: Zoom::new(),
-        }
-    }
-
     /// Returns the state of the cursor position.
     pub fn cursor(&self) -> Option<Position> {
         self.cursor
@@ -52,7 +32,6 @@ impl Handler {
         &mut self,
         event: Event,
         screen_size: Size,
-        now: Instant,
         mesh: &Mesh<Point<3>>,
         camera: &mut Camera,
         actions: &mut Actions,
@@ -112,12 +91,24 @@ impl Handler {
     pub fn update(
         &mut self,
         delta_t: f64,
-        now: Instant,
         camera: &mut Camera,
-        size: Size,
+        screen_size: Size,
         mesh: &Mesh<Point<3>>,
     ) {
-        self.zoom.apply_to_camera(delta_t, camera);
+        let focus_point = camera.focus_point(screen_size, self.cursor(), mesh);
+        self.zoom.apply_to_camera(delta_t, focus_point, camera);
+    }
+}
+
+impl Default for Handler {
+    fn default() -> Self {
+        Self {
+            cursor: None,
+
+            movement: Movement::new(),
+            rotation: Rotation::new(),
+            zoom: Zoom::new(),
+        }
     }
 }
 

crates/fj-viewer/src/input/zoom.rs

@@ -1,6 +1,6 @@
 use fj_math::{Transform, Vector};
 
-use crate::camera::Camera;
+use crate::camera::{Camera, FocusPoint};
 
 pub struct Zoom {
     accumulated_delta: f64,
@@ -18,11 +18,20 @@ impl Zoom {
         self.accumulated_delta += delta;
     }
 
-    pub fn apply_to_camera(&mut self, delta_t: f64, camera: &mut Camera) {
+    pub fn apply_to_camera(
+        &mut self,
+        delta_t: f64,
+        focus_point: FocusPoint,
+        camera: &mut Camera,
+    ) {
+        let distance = match focus_point.0 {
+            Some(fp) => (fp - camera.position()).magnitude(),
+            None => camera.position().coords.magnitude(),
+        };
         let displacement = self.accumulated_delta
             * delta_t
             * ZOOM_FACTOR
-            * camera.position().coords.magnitude().into_f64();
+            * distance.into_f64();
         camera.translation = camera.translation
             * Transform::translation(Vector::from([0.0, 0.0, -displacement]));
 

crates/fj-window/src/run.rs

@@ -36,7 +36,7 @@ pub fn run(
 
     let mut previous_time = Instant::now();
 
-    let mut input_handler = input::Handler::new(previous_time);
+    let mut input_handler = input::Handler::default();
     let mut renderer = block_on(Renderer::new(&window))?;
 
     let mut draw_config = DrawConfig::default();
@@ -182,7 +182,6 @@ pub fn run(
                 if let (Some(shape), Some(camera)) = (&shape, &mut camera) {
                     input_handler.update(
                         delta_t.as_secs_f64(),
-                        now,
                         camera,
                         window.size(),
                         &shape.mesh,
@@ -213,7 +212,6 @@ pub fn run(
             input_handler.handle_event(
                 event,
                 window.size(),
-                now,
                 &shape.mesh,
                 camera,
                 &mut actions,