egui: add bottom bar displaying cursor position

Useful for writing tests.

src/bin/topola-egui/app.rs

@@ -40,7 +40,10 @@ use topola::{
     specctra::{design::SpecctraDesign, mesadata::SpecctraMesadata},
 };
 
-use crate::{layers::Layers, overlay::Overlay, painter::Painter, top::Top, viewport::Viewport};
+use crate::{
+    bottom::Bottom, layers::Layers, overlay::Overlay, painter::Painter, top::Top,
+    viewport::Viewport,
+};
 
 #[derive(Debug, Default)]
 pub struct SharedData {
@@ -74,6 +77,9 @@ pub struct App {
     #[serde(skip)]
     top: Top,
 
+    #[serde(skip)]
+    bottom: Bottom,
+
     #[serde(skip)]
     layers: Option<Layers>,
 }
@@ -87,6 +93,7 @@ impl Default for App {
             text_channel: channel(),
             viewport: Viewport::new(),
             top: Top::new(),
+            bottom: Bottom::new(),
             layers: None,
         }
     }
@@ -198,7 +205,7 @@ impl eframe::App for App {
             }
         }
 
-        self.viewport.update(
+        let viewport_rect = self.viewport.update(
             ctx,
             &self.top,
             self.shared_data.clone(),
@@ -207,6 +214,8 @@ impl eframe::App for App {
             &self.layers,
         );
 
+        self.bottom.update(ctx, &self.viewport, viewport_rect);
+
         if ctx.input(|i| i.key_pressed(egui::Key::Escape)) {
             ctx.send_viewport_cmd(egui::ViewportCommand::Close);
         }

src/bin/topola-egui/bottom.rs

@@ -0,0 +1,19 @@
+use crate::viewport::Viewport;
+
+pub struct Bottom {}
+
+impl Bottom {
+    pub fn new() -> Self {
+        Self {}
+    }
+
+    pub fn update(&mut self, ctx: &egui::Context, viewport: &Viewport, viewport_rect: egui::Rect) {
+        egui::TopBottomPanel::bottom("bottom_panel").show(ctx, |ui| {
+            let transform = egui::emath::RectTransform::from_to(viewport.from_rect, viewport_rect);
+            let latest_pos = transform
+                .inverse()
+                .transform_pos(ctx.input(|i| i.pointer.latest_pos().unwrap_or_default()));
+            ui.label(format!("x: {} y: {}", latest_pos.x, latest_pos.y));
+        });
+    }
+}

src/bin/topola-egui/main.rs

@@ -1,6 +1,7 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
 
 mod app;
+mod bottom;
 mod layers;
 mod overlay;
 mod painter;

src/bin/topola-egui/viewport.rs

@@ -22,7 +22,7 @@ use crate::{
 };
 
 pub struct Viewport {
-    from_rect: egui::emath::Rect,
+    pub from_rect: egui::emath::Rect,
 }
 
 impl Viewport {
@@ -40,7 +40,7 @@ impl Viewport {
         maybe_invoker: &Option<Arc<Mutex<Invoker<SpecctraMesadata>>>>,
         maybe_overlay: &mut Option<Overlay>,
         maybe_layers: &Option<Layers>,
-    ) {
+    ) -> egui::Rect {
         egui::CentralPanel::default().show(ctx, |ui| {
             egui::Frame::canvas(ui.style()).show(ui, |ui| {
                 ui.ctx().request_repaint();
@@ -227,11 +227,11 @@ impl Viewport {
                                 egui::Color32::from_rgb(255, 255, 100),
                             );
                         }
-
-                        //unreachable!();
                     }
                 }
+
+                viewport_rect
             })
-        });
+        }).inner.inner
     }
 }