Export frames to PDF: use the asynchronous save dialog

Main's file dialogs answer asynchronously now (they no longer re-enter the
event loop on macOS); the menu item takes the path in a callback, and the test
draws a frame to let the dialog answer.

crates/ui-egui/src/menus.rs

@@ -160,10 +160,11 @@ pub fn invoke(app: &mut FigApp, id: &str) {
 /// Every visible top-level frame of the page as one PDF page each, through a save dialog.
 fn export_frames_pdf(app: &mut FigApp) {
     let name = app.session.doc().map(|d| d.name.clone()).unwrap_or_else(|_| "Untitled".into());
-    let Some(p) = app.services.pick_save(tr("Export"), &format!("{name}.pdf"), &["pdf"]) else { return };
-    if app.run("file.exportFramesPdf", json!({"path": p.to_string_lossy()})).is_some() {
-        app.toast(trf("Exported {name}", &[("name", &p.file_name().map(|f| f.to_string_lossy().to_string()).unwrap_or_default())]));
-    }
+    app.pick_save(tr("Export"), &format!("{name}.pdf"), &["pdf"], |app, p| {
+        if app.run("file.exportFramesPdf", json!({"path": p.to_string_lossy()})).is_some() {
+            app.toast(trf("Exported {name}", &[("name", &p.file_name().map(|f| f.to_string_lossy().to_string()).unwrap_or_default())]));
+        }
+    });
 }
 
 fn figcraft_svg_export(doc: &figcraft_doc::Document, ids: &[figcraft_doc::NodeId]) -> Option<String> {

crates/ui-egui/tests/file_menu_pdf.rs

@@ -5,14 +5,25 @@
 use std::path::PathBuf;
 
 use figcraft_engine::Session;
-use figcraft_ui_egui::{FigApp, Services, menus};
+use figcraft_ui_egui::{DialogFuture, FigApp, Services, menus};
 use serde_json::json;
 
 /// Services whose save dialog always returns the given path.
 struct SaveTo(PathBuf);
 impl Services for SaveTo {
-    fn pick_save(&mut self, _title: &str, _name: &str, _exts: &[&str]) -> Option<PathBuf> {
-        Some(self.0.clone())
+    fn pick_save(&mut self, _title: &str, _name: &str, _exts: &[&str]) -> DialogFuture {
+        Box::pin(std::future::ready(Some(self.0.clone())))
+    }
+}
+
+/// The menu item, then a frame: the save dialog answers asynchronously and the frame takes its answer.
+fn invoke(app: &mut FigApp, id: &str) {
+    menus::invoke(app, id);
+    let ctx = egui::Context::default();
+    for _ in 0..2 {
+        let input =
+            egui::RawInput { screen_rect: Some(egui::Rect::from_min_size(egui::Pos2::ZERO, egui::vec2(1440.0, 900.0))), ..Default::default() };
+        ctx.run_ui(input, |ui| app.ui(ui)).textures_delta.clear();
     }
 }
 
@@ -37,7 +48,7 @@ fn frames_pdf_menu_saves_the_pdf() {
     let path = out_path("one");
     let mut app = FigApp::new(Session::new(), Box::new(SaveTo(path.clone())));
     frame(&mut app, 0, 0);
-    menus::invoke(&mut app, "file.exportFramesPdf");
+    invoke(&mut app, "file.exportFramesPdf");
     assert!(app.ui.last_error.is_none(), "{:?}", app.ui.last_error);
     let bytes = std::fs::read(&path).expect("the menu writes the PDF where the user chose");
     let _ = std::fs::remove_file(&path);
@@ -60,7 +71,7 @@ fn frames_pdf_menu_one_page_per_visible_frame() {
     let hidden = frame(&mut app, 600, 0);
     let id = hidden["id"].clone();
     app.session.execute("node.set", &json!({"id": id, "visible": false})).unwrap();
-    menus::invoke(&mut app, "file.exportFramesPdf");
+    invoke(&mut app, "file.exportFramesPdf");
     assert!(app.ui.last_error.is_none(), "{:?}", app.ui.last_error);
     let bytes = std::fs::read(&path).expect("the menu writes the PDF where the user chose");
     let _ = std::fs::remove_file(&path);