ease zoom scale and position at the same time

calculates zoom bounds and interpolates those instead of interpolating
scale and position separately

crates/media/Cargo.toml

@@ -28,7 +28,7 @@ tempfile = "3.12.0"
 thiserror.workspace = true
 tracing = { version = "0.1", features = ["release_max_level_info"] }
 futures = "0.3.31"
-axum = "0.7.9"
+axum = { version = "0.7.9", features = ["macros", "ws"] }
 tokio.workspace = true
 
 [target.'cfg(target_os = "macos")'.dependencies]

crates/media/src/frame_ws.rs

@@ -23,6 +23,7 @@ pub async fn create_frame_ws(frame_rx: Receiver<WSFrame>) -> (u16, mpsc::Sender<
 
     type RouterState = Arc<Mutex<Receiver<WSFrame>>>;
 
+    #[axum::debug_handler]
     async fn ws_handler(
         ws: WebSocketUpgrade,
         State(state): State<RouterState>,

crates/rendering/src/lib.rs

@@ -667,7 +667,7 @@ impl ProjectUniforms {
 
         let interpolated_zoom = zoom_keyframes.interpolate(time as f64);
 
-        let (zoom_amount, zoom_origin) = {
+        let (zoom_amount, zoom_origin, lowered_zoom) = {
             let origin = match interpolated_zoom.position {
                 ZoomPosition::Manual { x, y } => Coord::<RawDisplayUVSpace>::new(XY {
                     x: x as f64,
@@ -691,7 +691,7 @@ impl ProjectUniforms {
                 }
             };
 
-            (interpolated_zoom.amount, origin)
+            (interpolated_zoom.amount, origin, interpolated_zoom.lowered)
         };
 
         let (display, zoom) = {
@@ -721,8 +721,21 @@ impl ProjectUniforms {
                 // padding: screen_scale_origin,
             };
 
-            let start = zoom.apply_scale(display_offset);
-            let end = zoom.apply_scale(end);
+            let target_size = end - display_offset;
+
+            let (zoom_start, zoom_end) = (
+                Coord::new(XY::new(
+                    lowered_zoom.top_left.0 as f64 * target_size.x,
+                    lowered_zoom.top_left.1 as f64 * target_size.y,
+                )),
+                Coord::new(XY::new(
+                    (lowered_zoom.bottom_right.0 as f64 - 1.0) * target_size.x,
+                    (lowered_zoom.bottom_right.1 as f64 - 1.0) * target_size.y,
+                )),
+            );
+
+            let start = display_offset + zoom_start;
+            let end = end + zoom_end;
 
             let target_size = end - start;
             let min_target_axis = target_size.x.min(target_size.y);