diff --git a/crates/ui-egui/src/canvas.rs b/crates/ui-egui/src/canvas.rs index 7d7fe8f6a..e5319a1aa 100644 --- a/crates/ui-egui/src/canvas.rs +++ b/crates/ui-egui/src/canvas.rs @@ -2576,6 +2576,18 @@ pub fn document_area(app: &mut PdfCraftApp, index: usize, ui: &mut egui::Ui) { // scroll bars float.) let max_y = (content_h - avail.height()).max(0.0); scroll = scroll.vertical_scroll_offset((r.top() - y_shift - GAP + frac * r.height()).max(0.0).min(max_y)); + // Horizontally too, as Acrobat does (#2665): beside a much wider page the others sit off + // to one side. A page already shown whole, or one filling the window's width, keeps the + // scroll, so paging through a zoomed-in document stays on the same column. Otherwise a + // page that fits is centred, and a wider one scrolled just far enough to fill the window. + // The page counts with its side gutters, which keep its edge clear of the floating + // quick-action bar as the layout does. + let (x, w) = (view.last_scroll.x, avail.width()); + let (left, right) = (r.left() - SIDE, r.right() + SIDE); + let target = if right - left <= w { if left >= x && right <= x + w { x } else { r.center().x - w / 2.0 } } else { x.clamp(left, right - w) }; + if (target - x).abs() > 0.5 { + scroll = scroll.horizontal_scroll_offset(target.clamp(0.0, (content_w - w).max(0.0))); + } } let ppp = ui.ctx().pixels_per_point(); let scale = view.render_scale(ppp); diff --git a/crates/ui-egui/tests/viewer.rs b/crates/ui-egui/tests/viewer.rs index d10051a56..1f0c8b09b 100644 --- a/crates/ui-egui/tests/viewer.rs +++ b/crates/ui-egui/tests/viewer.rs @@ -1860,3 +1860,27 @@ fn arrow_keys_follow_the_scroll_speed_preference() { let (slow, normal, fast) = (lines_to_page_2("slow"), lines_to_page_2("normal"), lines_to_page_2("fast")); assert!(fast * 3 < normal * 2 && normal * 3 < slow * 2, "presses to page 2: slow {slow}, normal {normal}, fast {fast}"); } + +/// #2665: next to a very wide page the normal pages sit far to its right, outside the window. +/// Going to one changed the page counter but kept the horizontal scroll, so it stayed out of +/// sight; as in Acrobat, it is brought into view. +#[test] +fn go_to_page_brings_the_page_into_view_horizontally() { + use pdfcraft_ui_egui::canvas::Fit; + let mut h = Harness::builder().with_size(egui::vec2(1400.0, 900.0)).build_eframe(|_cc| { + let mut app = PdfCraftApp::new(); + app.set_option("language", "en").unwrap(); + app.open_bytes("wide.pdf", None, sized_fixture(&[(595, 842), (595, 842), (595, 842), (6000, 2000)])).unwrap(); + app.views[0].fit = Fit::None; + app.views[0].zoom = 1.0; + app + }); + h.run_steps(4); + assert!(h.state().views[0].page_screen_rect(0).is_none(), "page 1 starts off-screen, right of the window"); + h.state_mut().views[0].go_to_page(2); + h.run_steps(4); + let v = &h.state().views[0]; + assert_eq!(v.current, 2); + let (r, vp) = (v.page_screen_rect(2).expect("page 3 on screen"), v.viewport_rect()); + assert!(r.left() >= vp.left() && r.right() <= vp.right(), "page 3 at {r:?}, viewport {vp:?}"); +}