fix(ui): Fill & Sign font size resizes the selected text (#1274)

The Font size control on the Fill & Sign bar only set the size of text
typed afterwards; text already placed and picked up kept its size, so the
only way to resize it was to type it again. With a placed Fill & Sign text
or date selected, a size typed into the control (or the end of a drag) now
applies to it through Edit::FontSizeAnnotation, one undo step per change.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RUNQSPVXx3dDBabRZHAnjz

crates/ui-egui/src/canvas.rs

@@ -4582,12 +4582,29 @@ fn quick_bar(app: &mut PdfCraftApp, area: Rect, ui: &mut egui::Ui) {
                         });
                     if matches!(current_fill, Some(crate::fill_sign::FillTool::Text | crate::fill_sign::FillTool::Date)) {
                         ui.label(tl!("Font size:"));
-                        ui.add(
+                        let size = ui.add(
                             egui::DragValue::new(&mut app.fill_text_size)
                                 .range(crate::fill_sign::MIN_TEXT_SIZE..=crate::fill_sign::MAX_TEXT_SIZE)
                                 .speed(0.25)
                                 .suffix(" pt"),
                         );
+                        // #1274: the size also applies to the Fill & Sign text that is selected,
+                        // once per change (a typed value, or the end of a drag), so a drag adds
+                        // one undo step and not one per frame.
+                        if ((size.changed() && !size.dragged()) || size.drag_stopped())
+                            && let Some((index, id)) = app.active_ids()
+                            && let Some((page, annotation)) = app.views.get(index).and_then(|view| view.comments.selected)
+                            && app.session.get(id).is_some_and(|doc| {
+                                doc.allows_annotation()
+                                    && doc
+                                        .info
+                                        .annotations
+                                        .iter()
+                                        .any(|a| a.page == page && a.index == annotation && a.fill_sign && a.subtype == "FreeText" && !a.locked)
+                            })
+                        {
+                            app.apply_edit(Edit::FontSizeAnnotation { page, index: annotation, size: app.fill_text_size });
+                        }
                     }
                     if let QuickTool::Comment(tool) = app.quick_tool {
                         let (r, _) = ui.allocate_exact_size(vec2(32.0, 9.0), Sense::hover());

crates/ui-egui/tests/fill_sign.rs

@@ -168,6 +168,60 @@ fn fill_text_size_controls_new_text_and_survives_settings_restore() {
     assert_eq!(restored.fill_text_size, 24.0, "invalid settings do not change the size");
 }
 
+/// #1274: with a placed Fill & Sign text selected, the Font size control resizes that text,
+/// not only text typed afterwards; with nothing selected it changes nothing on the page.
+#[test]
+fn fill_text_size_resizes_the_selected_text() {
+    let mut h = harness();
+    h.state_mut().execute("sign.fill.text");
+    click(&mut h, 50.0, 250.0);
+    h.event(egui::Event::Text("Resize me".into()));
+    h.run_steps(1);
+    h.key_press(egui::Key::Enter);
+    h.run_steps(3);
+    let height = |h: &Harness<'static, PdfCraftApp>| {
+        let s = h.state();
+        let a = s.session.get(s.views[0].id).unwrap().info.annotations.iter().find(|a| a.contents.as_deref() == Some("Resize me")).cloned().unwrap();
+        a.rect[3] - a.rect[1]
+    };
+    let before = height(&h);
+    let set_size = |h: &mut Harness<'static, PdfCraftApp>, value: &str| {
+        h.query_all_by_role(egui::accesskit::Role::SpinButton)
+            .find(|n| n.value().is_some_and(|v| v.ends_with(" pt")))
+            .expect("the Font size control")
+            .click();
+        h.run_steps(2);
+        h.key_press_modifiers(egui::Modifiers::COMMAND, egui::Key::A);
+        h.event(egui::Event::Text(value.into()));
+        h.run_steps(1);
+        h.key_press(egui::Key::Enter);
+        h.run_steps(4);
+    };
+    // Nothing selected: only the size for new text changes.
+    h.state_mut().views[0].comments.selected = None;
+    set_size(&mut h, "18");
+    assert_eq!(h.state().fill_text_size, 18.0);
+    assert_eq!(height(&h), before, "an unselected placed text keeps its size");
+    // The placed text picked up with the Add text tool, then resized.
+    let annotation = {
+        let s = h.state();
+        s.session
+            .get(s.views[0].id)
+            .unwrap()
+            .info
+            .annotations
+            .iter()
+            .find(|a| a.contents.as_deref() == Some("Resize me"))
+            .map(|a| (a.page, a.index))
+            .unwrap()
+    };
+    h.state_mut().views[0].comments.selected = Some(annotation);
+    set_size(&mut h, "36");
+    assert_eq!(h.state().fill_text_size, 36.0);
+    let after = height(&h);
+    assert!(after > before * 2.0, "36 pt text has a taller box than 10 pt text: {before} -> {after}");
+}
+
 #[test]
 fn the_type_box_grows_as_text_is_typed() {
     let mut h = harness();