Add GraphLayout::pointer_target()

ramen_egui/src/lib.rs

@@ -10,7 +10,6 @@ pub enum PointerTarget {
     Node(usize),
     Input(SlotIndex),
     Output(SlotIndex),
-    Edge(Edge),
 }
 
 #[derive(Debug)]
@@ -18,7 +17,7 @@ pub struct EdgeLayout {
     pub points: [Vec2; 4],
 }
 
-#[derive(Debug)]
+#[derive(Clone, Debug)]
 pub struct GraphStyle {
     pub grid_spacing: f32,
     pub grid_stroke: Stroke,
@@ -34,7 +33,7 @@ pub struct GraphStyle {
 impl GraphStyle {
     pub fn from_ui_style(style: &egui::Style) -> Self {
         let node_alpha = 192;
-        
+
         let node_bg = if style.visuals.dark_mode {
             Color32::from_black_alpha(node_alpha)
         } else {
@@ -55,8 +54,9 @@ impl GraphStyle {
     }
 }
 
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct GraphLayout {
+    pub style: GraphStyle,
     pub node_rects: HashMap<usize, egui::Rect>,
     pub input_positions: HashMap<SlotIndex, Vec2>,
     pub output_positions: HashMap<SlotIndex, Vec2>,
@@ -65,7 +65,14 @@ pub struct GraphLayout {
 
 impl GraphLayout {
     pub fn layout(style: &GraphStyle, graph: &Graph) -> Self {
-        let mut layout = Self::default();
+        let mut layout = Self {
+            style: style.clone(),
+            node_rects: Default::default(),
+            input_positions: Default::default(),
+            output_positions: Default::default(),
+            edges: Default::default(),
+        };
+
         let mut edges = Vec::new();
 
         for (node_index, node) in graph.nodes.iter() {
@@ -129,6 +136,39 @@ impl GraphLayout {
 
         layout
     }
+
+    pub fn pointer_target(&self, pointer: egui::Pos2) -> PointerTarget {
+        let test_slots = |positions: &HashMap<SlotIndex, Vec2>| -> Option<SlotIndex> {
+            for (index, position) in positions.iter() {
+                let dx = pointer.x - position.x;
+                let dy = pointer.y - position.y;
+                let d2 = (dx * dx) + (dy * dy);
+                let slot_radius2 = self.style.slot_radius.powi(2);
+
+                if d2 < slot_radius2 {
+                    return Some(*index);
+                }
+            }
+
+            None
+        };
+        
+        if let Some(index) = test_slots(&self.input_positions) {
+            return PointerTarget::Input(index);
+        }
+        
+        if let Some(index) = test_slots(&self.output_positions) {
+            return PointerTarget::Output(index);
+        }
+        
+        for (node_index, node_rect) in self.node_rects.iter() {
+            if node_rect.contains(pointer) {
+                return PointerTarget::Node(*node_index);
+            }
+        }
+
+        PointerTarget::Grid
+    }
 }
 
 pub fn draw_graph(ui: &mut egui::Ui, graph: &Graph) {
@@ -140,7 +180,7 @@ pub fn draw_graph(ui: &mut egui::Ui, graph: &Graph) {
     let layout = GraphLayout::layout(&style, graph);
 
     let pointer_pos = ui.input().pointer.interact_pos();
-    let mut pointer_target: Option<PointerTarget> = None;
+    let pointer_target = pointer_pos.map(|pointer| layout.pointer_target(pointer));
 
     let grid_spacing = style.grid_spacing;
     let grid_pos = rect.left_top().to_vec2() / egui::vec2(grid_spacing, grid_spacing);