egui: add error messages dialog

locales/en-US/main.ftl

@@ -39,3 +39,7 @@ show-layer-manager = Show Layer Manager
 frame-timestep = Frame Timestep
 
 specctra-session-file = Specctra session file
+
+title-error-messages = Error Messages
+reset-error-messages = Reset Messages
+discard-item = Discard

src/bin/topola-egui/app.rs

@@ -40,6 +40,7 @@ use topola::{
 use crate::{
     activity::{ActivityStatus, ActivityWithStatus},
     bottom::Bottom,
+    error_dialog::ErrorDialog,
     file_receiver::FileReceiver,
     layers::Layers,
     overlay::Overlay,
@@ -79,6 +80,9 @@ pub struct App {
     #[serde(skip)]
     bottom: Bottom,
 
+    #[serde(skip)]
+    error_dialog: ErrorDialog,
+
     #[serde(skip)]
     maybe_layers: Option<Layers>,
 
@@ -101,6 +105,7 @@ impl Default for App {
             viewport: Viewport::new(),
             top: Top::new(),
             bottom: Bottom::new(),
+            error_dialog: ErrorDialog::new(),
             maybe_layers: None,
             maybe_design: None,
             update_counter: 0.0,
@@ -206,6 +211,9 @@ impl eframe::App for App {
             }
         }
 
+        self.error_dialog
+            .update(ctx, &self.translator, &self.viewport);
+
         let viewport_rect = self.viewport.update(
             ctx,
             &self.top,

src/bin/topola-egui/error_dialog.rs

@@ -0,0 +1,90 @@
+//! dialog for error messages (e.g. for displaying file parser errors)
+
+use std::collections::BTreeSet;
+use std::sync::Arc;
+
+use crate::{translator::Translator, viewport::Viewport};
+
+pub struct ErrorDialog {
+    pub messages: Vec<(&'static str, String)>,
+    pub window_open: bool,
+}
+
+impl ErrorDialog {
+    pub fn new() -> Self {
+        Self {
+            messages: Vec::new(),
+            window_open: false,
+        }
+    }
+
+    // this is a separate method in order to intercept error messages
+    // and also print them to the console.
+    pub fn push_error(&mut self, component_id: &'static str, message: String) {
+        // note that the message here is already localized, and perhaps less useful.
+        log::info!("{}: {}", component_id, &message);
+        self.messages.push((component_id, message));
+        self.window_open = true;
+    }
+
+    pub fn update(&mut self, ctx: &egui::Context, tr: &Translator, viewport: &Viewport) {
+        let mut messages_cleared = false;
+        egui::Window::new(tr.text("title-error-messages"))
+            .id("error-messages-dialog".into())
+            .open(&mut self.window_open)
+            .scroll(true)
+            .show(ctx, |ui| {
+                if ui.button(tr.text("reset-error-messages")).clicked() {
+                    self.messages.clear();
+                    messages_cleared = true;
+                }
+
+                egui::Grid::new("error-messages-grid").show(ui, |ui| {
+                    let mut messages_to_discard = BTreeSet::<usize>::new();
+                    let style = Arc::clone(ui.style());
+                    for (msg_id, msg) in self.messages.iter().enumerate() {
+                        use egui::style::{FontSelection, TextStyle};
+                        use egui::text::{LayoutJob, TextWrapping};
+                        use egui::widget_text::{RichText, WidgetText};
+                        use egui::{Align, FontFamily, FontId, TextFormat};
+
+                        let mut loj = LayoutJob::default();
+                        loj.break_on_newline = true;
+                        loj.wrap.max_width = 200.0;
+                        RichText::new(&(tr.text(msg.0) + ": "))
+                            .strong()
+                            .color(style.visuals.text_color())
+                            .append_to(&mut loj, &style, FontSelection::Default, Align::Min);
+                        RichText::new(&msg.1)
+                            .color(style.visuals.text_color())
+                            .append_to(
+                                &mut loj,
+                                &style,
+                                FontSelection::Style(TextStyle::Monospace),
+                                Align::Min,
+                            );
+
+                        // TODO: perhaps alternatively, use small icon instead?
+                        //   (provide alt text in that case!)
+                        if ui.add(egui::Button::new(tr.text("discard-item"))).clicked() {
+                            messages_to_discard.insert(msg_id);
+                        }
+                        ui.label(WidgetText::LayoutJob(loj));
+                        ui.end_row();
+                    }
+                    if !messages_to_discard.is_empty() {
+                        let mut count = 0;
+                        self.messages.retain(|_| {
+                            let ret = !messages_to_discard.contains(&count);
+                            count += 1;
+                            ret
+                        });
+                    }
+                });
+            });
+
+        if messages_cleared {
+            self.window_open = false;
+        }
+    }
+}

src/bin/topola-egui/main.rs

@@ -4,6 +4,7 @@ mod action;
 mod activity;
 mod app;
 mod bottom;
+mod error_dialog;
 mod file_receiver;
 mod file_sender;
 mod layers;