Focus last selected node

scripts/force-directed-graph/src/lib.rs

@@ -35,6 +35,11 @@ impl Body {
     }
 
     pub fn update(&mut self, dt: f32) {
+        if self.fixed {
+            self.velocity = Vec2::ZERO;
+            return;
+        }
+
         let pos = self.position;
         let vel = self.velocity;
         let acc = self.acceleration;
@@ -293,7 +298,7 @@ impl ForceGraph {
                 let from = from.body.position + from.body.velocity * dt;
                 let to = to.body.position + to.body.velocity * dt;
                 let delta = to - from;
-                spring.apply(delta) // * dt
+                spring.apply(delta)
             });
 
             if let Some(vel) = vel {
@@ -446,6 +451,10 @@ export_abi!(ForceDirectedGraphPanel);
 pub struct ForceDirectedGraphPanel {
     panel: Panel,
     graph: ForceGraph,
+    center: Vec2,
+    last_focus: Vec2,
+    focus_anim: f32,
+    focus_target: usize,
     size: Vec2,
 }
 
@@ -456,6 +465,10 @@ impl BindPanel for ForceDirectedGraphPanel {
         let panel = Self {
             panel,
             graph,
+            last_focus: Vec2::ZERO,
+            center: Vec2::ZERO,
+            focus_anim: 1.0,
+            focus_target: 0,
             size: Vec2::splat(100.0),
         };
         Box::new(panel)
@@ -465,10 +478,23 @@ impl BindPanel for ForceDirectedGraphPanel {
 impl PanelImpl for ForceDirectedGraphPanel {
     fn update(&mut self, dt: f32) {
         self.graph.update(dt);
+        self.focus_anim += dt;
+
+        let target_pos = self.graph.nodes[self.focus_target].body.position;
+        let anim = self.focus_anim / 0.5;
+        if anim < 0.0 {
+            self.center = self.last_focus;
+        } else if anim < 1.0 {
+            let anim = -(anim * (anim - 2.0));
+            self.center = target_pos * anim + self.last_focus * (1.0 - anim);
+        } else {
+            self.center = target_pos;
+        }
     }
 
     fn draw(&mut self) {
-        let ctx = DrawContext::new(self.panel).with_offset(self.size / 2.0);
+        let offset = self.size / 2.0 - self.center;
+        let ctx = DrawContext::new(self.panel).with_offset(offset);
         self.graph.draw(&ctx);
     }
 
@@ -477,7 +503,8 @@ impl PanelImpl for ForceDirectedGraphPanel {
     }
 
     fn on_cursor_event(&mut self, kind: CursorEventKind, at: Vec2) {
-        let at = at - self.size / 2.0;
+        let offset = self.size / 2.0 - self.center;
+        let at = at - offset;
         if let CursorEventKind::Deselect = kind {
             let node = self
                 .graph
@@ -486,6 +513,9 @@ impl PanelImpl for ForceDirectedGraphPanel {
                 .position(|node| !node.info.hidden && node.body.position.distance(at) < 6.0);
             if let Some(node) = node {
                 self.graph.on_select(node);
+                self.last_focus = self.center;
+                self.focus_target = node;
+                self.focus_anim = 0.0;
             }
         }
     }