feat(topola-egui): Allow using Shift+{arrow keys} to scroll viewport using keyboard

Fixes #188.

crates/topola-egui/src/action.rs

@@ -81,12 +81,16 @@ impl Trigger {
 }
 
 impl Switch {
-    pub fn toggle_widget(&self, _ctx: &egui::Context, ui: &mut egui::Ui, selected: &mut bool) {
+    pub fn toggle_widget(&self, ui: &mut egui::Ui, selected: &mut bool) {
         ui.toggle_value(selected, self.action.widget_text());
     }
 
+    pub fn checkbox(&self, ui: &mut egui::Ui, selected: &mut bool) {
+        ui.checkbox(selected, self.action.widget_text());
+    }
+
     pub fn consume_key_enabled(
-        &mut self,
+        &self,
         ctx: &egui::Context,
         _ui: &mut egui::Ui,
         selected: &mut bool,

crates/topola-egui/src/actions.rs

@@ -166,6 +166,7 @@ pub struct ViewActions {
     pub zoom_to_fit: Switch,
     pub show_ratsnest: Switch,
     pub show_navmesh: Switch,
+    pub show_topo_navmesh: Switch,
     pub show_bboxes: Switch,
     pub show_origin_destination: Switch,
     pub show_appearance_panel: Switch,
@@ -177,6 +178,8 @@ impl ViewActions {
             zoom_to_fit: Action::new_keyless(tr.text("tr-menu-view-zoom-to-fit")).into_switch(),
             show_ratsnest: Action::new_keyless(tr.text("tr-menu-view-show-ratsnest")).into_switch(),
             show_navmesh: Action::new_keyless(tr.text("tr-menu-view-show-navmesh")).into_switch(),
+            show_topo_navmesh: Action::new_keyless(tr.text("tr-menu-view-show-topo-navmesh"))
+                .into_switch(),
             show_bboxes: Action::new_keyless(tr.text("tr-menu-view-show-bboxes")).into_switch(),
             show_origin_destination: Action::new_keyless(
                 tr.text("tr-menu-view-show-origin-destination"),
@@ -196,42 +199,30 @@ impl ViewActions {
         viewport: &mut Viewport,
         have_workspace: bool,
     ) {
-        ui.toggle_value(
-            &mut viewport.scheduled_zoom_to_fit,
-            tr.text("tr-menu-view-zoom-to-fit"),
-        );
+        self.zoom_to_fit
+            .toggle_widget(ui, &mut viewport.scheduled_zoom_to_fit);
 
         ui.separator();
-
         ui.add_enabled_ui(have_workspace, |ui| {
-            ui.checkbox(
-                &mut menu_bar.show_ratsnest,
-                tr.text("tr-menu-view-show-ratsnest"),
-            );
-            ui.checkbox(
-                &mut menu_bar.show_navmesh,
-                tr.text("tr-menu-view-show-navmesh"),
-            );
-            ui.checkbox(
-                &mut menu_bar.show_topo_navmesh,
-                tr.text("tr-menu-view-show-topo-navmesh"),
-            );
-            ui.checkbox(
-                &mut menu_bar.show_bboxes,
-                tr.text("tr-menu-view-show-bboxes"),
-            );
-            ui.checkbox(
-                &mut menu_bar.show_origin_destination,
-                tr.text("tr-menu-view-show-origin-destination"),
-            );
+            self.show_ratsnest.checkbox(ui, &mut menu_bar.show_ratsnest);
+            self.show_navmesh.checkbox(ui, &mut menu_bar.show_navmesh);
+            self.show_topo_navmesh
+                .checkbox(ui, &mut menu_bar.show_topo_navmesh);
+            self.show_bboxes.checkbox(ui, &mut menu_bar.show_bboxes);
+            self.show_origin_destination
+                .checkbox(ui, &mut menu_bar.show_origin_destination);
         });
 
         ui.separator();
+        self.show_appearance_panel
+            .checkbox(ui, &mut menu_bar.show_appearance_panel);
 
-        ui.checkbox(
-            &mut menu_bar.show_appearance_panel,
-            tr.text("tr-menu-view-show-layer-manager"),
-        );
+        ui.separator();
+        ui.label(tr.text("tr-menu-view-kdb-scroll-delta-factor"));
+        ui.add(egui::widgets::Slider::new(
+            &mut viewport.kbd_scroll_delta_factor,
+            1.0..=100.0,
+        ));
     }
 }
 
@@ -259,7 +250,7 @@ impl PlaceActions {
         is_placing_via: &mut bool,
     ) -> egui::InnerResponse<()> {
         ui.add_enabled_ui(have_workspace, |ui| {
-            self.place_via.toggle_widget(ctx, ui, is_placing_via);
+            self.place_via.toggle_widget(ui, is_placing_via);
         })
     }
 }

crates/topola-egui/src/app.rs

@@ -18,8 +18,8 @@ use topola::{
 };
 
 use crate::{
-    config::Config, error_dialog::ErrorDialog, menu_bar::MenuBar, status_bar::StatusBar,
-    translator::Translator, viewport::Viewport, workspace::Workspace,
+    actions::Actions, config::Config, error_dialog::ErrorDialog, menu_bar::MenuBar,
+    status_bar::StatusBar, translator::Translator, viewport::Viewport, workspace::Workspace,
 };
 
 pub struct App {

crates/topola-egui/src/viewport.rs

@@ -27,10 +27,14 @@ use topola::{
     router::navmesh::NavvertexIndex,
 };
 
-use crate::{config::Config, menu_bar::MenuBar, painter::Painter, workspace::Workspace};
+use crate::{
+    actions::Actions, config::Config, menu_bar::MenuBar, painter::Painter, workspace::Workspace,
+};
 
 pub struct Viewport {
     pub transform: egui::emath::TSTransform,
+    /// how much should a single arrow key press scroll
+    pub kbd_scroll_delta_factor: f32,
     pub scheduled_zoom_to_fit: bool,
 }
 
@@ -38,6 +42,7 @@ impl Viewport {
     pub fn new() -> Self {
         Self {
             transform: egui::emath::TSTransform::new([0.0, 0.0].into(), 0.01),
+            kbd_scroll_delta_factor: 5.0,
             scheduled_zoom_to_fit: false,
         }
     }
@@ -52,6 +57,7 @@ impl Viewport {
         egui::CentralPanel::default()
             .show(ctx, |ui| {
                 egui::Frame::canvas(ui.style()).show(ui, |ui| {
+                    // TODO: only request re-render if anything changed
                     ui.ctx().request_repaint();
 
                     let (id, viewport_rect) = ui.allocate_space(ui.available_size());
@@ -68,7 +74,52 @@ impl Viewport {
 
                     self.transform.translation +=
                         latest_pos.to_vec2() * (old_scaling - self.transform.scaling);
-                    self.transform.translation += ctx.input(|i| i.smooth_scroll_delta);
+
+                    // disable built-in behavior of arrow keys
+                    if response.has_focus() {
+                        response.ctx.memory_mut(|m| {
+                            // we are only allowed to modify the focus lock filter if we have focus
+                            m.set_focus_lock_filter(
+                                id,
+                                egui::EventFilter {
+                                    horizontal_arrows: true,
+                                    vertical_arrows: true,
+                                    ..Default::default()
+                                },
+                            );
+                        });
+                    }
+
+                    self.transform.translation += ctx.input_mut(|i| {
+                        // handle scrolling
+                        let mut scroll_delta = core::mem::take(&mut i.smooth_scroll_delta);
+
+                        // arrow keys
+                        let kbd_sdf = self.kbd_scroll_delta_factor;
+                        let mut pressed = |key| {
+                            i.consume_shortcut(&egui::KeyboardShortcut::new(
+                                egui::Modifiers::SHIFT,
+                                key,
+                            ))
+                        };
+                        use egui::Key;
+                        scroll_delta.y += if pressed(Key::ArrowDown) {
+                            kbd_sdf
+                        } else if pressed(Key::ArrowUp) {
+                            -kbd_sdf
+                        } else {
+                            0.0
+                        };
+                        scroll_delta.x += if pressed(Key::ArrowRight) {
+                            kbd_sdf
+                        } else if pressed(Key::ArrowLeft) {
+                            -kbd_sdf
+                        } else {
+                            0.0
+                        };
+
+                        scroll_delta
+                    });
 
                     let mut painter = Painter::new(ui, self.transform, menu_bar.show_bboxes);
 

locales/en-US/main.ftl

@@ -26,6 +26,7 @@ tr-menu-view-show-topo-navmesh = Show Topological Navmesh
 tr-menu-view-show-bboxes = Show BBoxes
 tr-menu-view-show-origin-destination = Show Origin–Destination
 tr-menu-view-show-layer-manager = Show Layer Manager
+tr-menu-view-kdb-scroll-delta-factor = Keyboard scroll delta factor
 tr-menu-view-frame-timestep = Frame Timestep
 
 tr-menu-place = Place