delete nodes & edges

src/main.rs

@@ -1,23 +1,37 @@
 use eframe::{App, CreationContext, NativeOptions, run_native};
-use egui::Context;
-use egui_graphs::{DefaultGraphView, Graph};
-use petgraph::stable_graph::StableGraph;
+use egui::{Context, Key};
+use egui_graphs::{DefaultGraphView, Graph, SettingsInteraction};
+use petgraph::prelude::{EdgeIndex, NodeIndex, StableGraph};
 
-pub struct BasicApp {
+pub struct BrainWave {
     g: Graph,
 }
 
-impl BasicApp {
+impl BrainWave {
     fn new(_: &CreationContext<'_>) -> Self {
         let g = generate_graph();
         Self { g: Graph::from(&g) }
     }
 }
 
-impl App for BasicApp {
+impl App for BrainWave {
     fn update(&mut self, ctx: &Context, _: &mut eframe::Frame) {
         egui::CentralPanel::default().show(ctx, |ui| {
-            ui.add(&mut DefaultGraphView::new(&mut self.g));
+            ui.add(
+                &mut DefaultGraphView::new(&mut self.g).with_interactions(
+                    &SettingsInteraction::new()
+                        .with_dragging_enabled(true)
+                        .with_node_selection_enabled(true)
+                        .with_edge_selection_enabled(true)
+                        .with_node_selection_multi_enabled(true)
+                        .with_edge_selection_multi_enabled(true),
+                ),
+            );
+            ui.input(|input| {
+                if input.key_pressed(Key::Delete) {
+                    handle_graph_delete(&mut self.g);
+                }
+            })
         });
     }
 }
@@ -31,16 +45,45 @@ fn generate_graph() -> StableGraph<(), ()> {
 
     g.add_edge(a, b, ());
     g.add_edge(b, c, ());
-    g.add_edge(c, a, ());
 
     g
 }
 
+fn handle_graph_delete(graph: &mut Graph) {
+    enum EdgeOrNode {
+        Edge(EdgeIndex),
+        Node(NodeIndex),
+    }
+    let mut to_remove = Vec::new();
+    {
+        let snodes = graph.selected_nodes();
+        let sedges = graph.selected_edges();
+        if snodes.len() + sedges.len() != 0 {
+            for node in snodes {
+                to_remove.push(EdgeOrNode::Node(*node));
+            }
+            for edge in sedges {
+                to_remove.push(EdgeOrNode::Edge(*edge));
+            }
+        }
+    }
+    for e in to_remove {
+        match e {
+            EdgeOrNode::Edge(edge_index) => {
+                graph.remove_edge(edge_index);
+            }
+            EdgeOrNode::Node(node_index) => {
+                graph.remove_node(node_index);
+            }
+        }
+    }
+}
+
 fn main() {
     run_native(
         "basic",
         NativeOptions::default(),
-        Box::new(|cc| Ok(Box::new(BasicApp::new(cc)))),
+        Box::new(|cc| Ok(Box::new(BrainWave::new(cc)))),
     )
     .unwrap();
 }