Files
overleaf-cep/services
Alf Eaton 17dd108ce1 Wrap PDF setDocument in startViewTransition (#33346)
* Set scale synchronously on pagesinit to prevent 1.333 DPI flash

PDF.js resets its internal scale to 1.0 when setDocument() is called,
causing pages to momentarily render at the default 96/72 DPI scale
(1.333) before the React restore effect can apply the correct value.
Setting currentScaleValue directly in the pagesinit handler eliminates
this one-frame wrong-scale flash.

* Override .page display to block to prevent horizontal jump on recompile

Overleaf's global .loading class sets display:inline-flex, which
collides with PDF.js's transient 'loading' class on .page elements.
When the loading class is applied, inline-flex breaks margin:auto
centering, causing the page to jump horizontally. Forcing display:block
at higher specificity prevents the global rule from taking effect.

* Fix scrollToPosition offset using marginTop instead of borderWidth

scrollPageIntoView aligns the page content edge with the container top,
leaving scrollTop equal to the page's top margin (12px) rather than 0.
The previous correction used borderWidth (effectively 0) so the margin
offset was never compensated. Using marginTop scrolls back the correct
amount so the margin above the first page is visible.

* Prevent PDF viewer collapsing during recompile by preserving height

When setDocument() is called with a new PDF, _resetView() synchronously
clears all page elements, briefly collapsing the .pdfViewer div to the
viewport height. This produces a visible flicker before pagesinit fires
and pages are re-added.

Fix: record the current height and pin it as min-height on the .pdfViewer
element before calling setDocument(). A one-shot pagesinit listener
removes the constraint once the new pages are initialised at the correct
scale, by which point the element is already at its correct final height.

* Suppress PDF.js page-level loading spinner in Overleaf viewer

The PDF.js loadingIcon/loading classes briefly add a ::after pseudo-element
with display:block and contain:strict to each page div. Overleaf has its
own loading state UI so the spinner is redundant, and its activation was
the root cause of the shifts 4-5 height oscillation (the display change
broke CSS margin collapse on .pdfViewer, adding 2x page margins to its
computed height).

The display:block rule already added to .page prevents the direct cause
(Overleaf's .loading{display:inline-flex} colliding with the PDF.js class).
This rule makes the intent explicit by zeroing the ::after entirely.

* Wrap PDF setDocument in startViewTransition

---------

Co-authored-by: Brian Gough <brian.gough@overleaf.com>
GitOrigin-RevId: 353ab865de3c7872363a61592d86390dfc34dacc
2026-05-12 08:05:53 +00:00
..