M3: a newly opened document starts at the top, not where the last session scrolled (#554)

Opening a PDF after a restart showed it part-way down, at the page some
other document had been left on in the previous session.

Since #259 (#189) the page view's ScrollArea is salted with the
document's DocId, so each tab keeps its own offset. eframe persists
egui's memory (persist_egui_memory defaults to true) to app.ron every
30 s and on quit, scroll offsets included, and restores it at the next
launch. DocIds start again at 1 every launch, so the first document
opened inherited the offset stored under id 1 last time, the second the
one under id 2, and so on.

A DocView now notes when its page view is first shown, and that frame
sets the scroll offset to zero. Navigation queued before the first frame
still wins: a zoom anchor or `goto` (--page, the PDF's open action,
reopening the last session's files at their pages, #462) is applied on
top. Tabs that were already shown keep their own position, as #189
needs. egui's other persisted memory (panel sizes and the like) is
untouched.

- canvas: `DocView::shown`, reset of the offset on the first frame
- tests/viewer.rs: a_new_document_opens_at_the_top_after_a_relaunch
  saves egui's memory through eframe's own RON storage path after
  scrolling a.pdf to page 4, restores it in a new app, opens c.pdf
  (DocId 1) and checks it starts on page 1 (it opened on page 4 before
  the fix) and then keeps its own position
- parity: the test is evidence on view.document-tabs

Refs #189, #259, #462.

Co-authored-by: lloyd <lloyd@stackworx.io>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
LloydNicholson
2026-10-09 12:19:10 -04:00
committed by GitHub
co-authored by lloyd Claude Opus 5.5
parent cc17deb634
commit 19625d40a8
3 changed files with 64 additions and 2 deletions
+2 -2
View File
@@ -1178,8 +1178,8 @@ milestone = "M3"
status = "shipped"
commands = []
tools = ["doc_list"]
evidence = ["crates/ui-egui/tests/editing.rs::combining_files_opens_a_new_unsaved_tab", "crates/ui-egui/tests/control.rs::state_and_view_options", "crates/ui-egui/tests/viewer.rs::each_document_keeps_its_own_scroll_position"]
notes = "each tab keeps its own scroll position (#189)"
evidence = ["crates/ui-egui/tests/editing.rs::combining_files_opens_a_new_unsaved_tab", "crates/ui-egui/tests/control.rs::state_and_view_options", "crates/ui-egui/tests/viewer.rs::each_document_keeps_its_own_scroll_position", "crates/ui-egui/tests/viewer.rs::a_new_document_opens_at_the_top_after_a_relaunch"]
notes = "each tab keeps its own scroll position (#189), and a newly opened one starts at the top, not where an earlier session left the scroll"
[[feature]]
id = "view.multiple-windows"