fix(ui): a narrow added-text box keeps its text at its own edge

The editor is at least 60 points wide on screen, so a short box can be
clicked into. With the box's alignment applied, right-aligned or centred
text in a box narrower than that was placed against the wider editor's
edge, past the box's right edge. The editor now reaches past a narrow
box away from the edge its text keeps, so the text stays where the page
draws it.

crates/ui-egui/src/content_ui.rs

@@ -537,6 +537,16 @@ pub(crate) fn editor(ctx: &egui::Context, view: &mut DocView, info: &DocInfo, ad
     }
     let r = screen_rect(&xf, info, page, draft.rect);
     let source_rect = draft.index.map(|_| screen_rect(&xf, info, page, draft.style.rect));
+    // At least 60 points wide, so a short box can still be clicked into. Where that is wider than
+    // the box, the editor reaches past it away from the edge its text keeps (the right edge for
+    // right-aligned text, both halves for centred), so the text stays where the page draws it.
+    let width = r.width().max(60.0);
+    let anchor = match draft.style.align {
+        pdfcraft_engine::TextAlign::Center => 0.5,
+        pdfcraft_engine::TextAlign::Right => 1.0,
+        pdfcraft_engine::TextAlign::Left | pdfcraft_engine::TextAlign::Justify => 0.0,
+    };
+    let at = r.min - egui::vec2((width - r.width()) * anchor, 0.0);
     let background_ready = draft.index.is_some_and(|index| view.text_background.ready_added(page, index));
     let tokens = Tokens::get(ctx);
     let (mut commit, mut cancel, mut done) = (false, false, false);
@@ -548,7 +558,7 @@ pub(crate) fn editor(ctx: &egui::Context, view: &mut DocView, info: &DocInfo, ad
     egui::Area::new(egui::Id::new(("added-text", view.id.0)))
         .fade_in(false)
         .order(egui::Order::Foreground)
-        .fixed_pos(r.min)
+        .fixed_pos(at)
         .constrain_to(view.viewport_rect())
         .constrain(false)
         .show(ctx, |ui| {
@@ -572,7 +582,7 @@ pub(crate) fn editor(ctx: &egui::Context, view: &mut DocView, info: &DocInfo, ad
                 let resp = ui.add(
                     egui::TextEdit::multiline(&mut t.text)
                         .font(font)
-                        .desired_width(r.width().max(60.0))
+                        .desired_width(width)
                         .desired_rows(1)
                         .horizontal_align(halign)
                         .background_color(if background_ready { Color32::TRANSPARENT } else { Color32::WHITE })

crates/ui-egui/tests/it/content.rs

@@ -737,6 +737,29 @@ fn the_text_editor_keeps_the_boxs_alignment() {
     assert!(left == 0 && right > 20, "the text is drawn at the right ({left} dark pixels left, {right} right)");
 }
 
+/// A box narrower than the editor's least width (60 points on screen): right-aligned text stays
+/// at the box's right edge, not the wider editor's, which lies past it.
+#[test]
+fn the_text_editor_aligns_a_narrow_box_to_its_own_edge() {
+    let _gpu = gpu();
+    let mut h = harness();
+    let rect = [40.0, 195.0, 60.0, 210.0];
+    let text = pdfcraft_engine::AddedText { rect, text: "Hi".into(), align: pdfcraft_engine::TextAlign::Right, ..Default::default() };
+    assert!(h.state_mut().apply_edit(pdfcraft_engine::Edit::AddText { page: 0, text }));
+    assert!(h.state_mut().execute("edit.text"));
+    h.run_steps(3);
+    let point = at(&h, 50.0, 195.0);
+    click(&mut h, point);
+    assert_eq!(h.state().views[0].content.draft.as_ref().and_then(|d| d.index), Some(0), "the editor opened on the text");
+    h.run_steps(3);
+    let r = item_on_screen(&h, rect);
+    assert!(r.width() < 60.0, "the box is narrower than the editor: {}", r.width());
+    let pixels = h.render().unwrap();
+    let inside = ink(&pixels, r);
+    let past = ink(&pixels, egui::Rect::from_min_max(pos2(r.right() + 2.0, r.min.y), pos2(r.right() + 40.0, r.max.y)));
+    assert!(inside > 20 && past == 0, "the text is drawn in its box ({inside} dark pixels in it, {past} past its right edge)");
+}
+
 fn mode_tab(h: &Harness<'static, PdfCraftApp>, label: &str) -> egui::Rect {
     h.get_all_by_role_and_label(egui::accesskit::Role::Button, label).map(|n| n.rect()).find(|r| r.bottom() < 120.0).expect("a mode tab")
 }