[Bug]: The rendering indicator is not always visible

[nicolo-ribaudo]

Attach (recommended) or Link to PDF file

This is not specific to any PDF file.

Web browser and its version

Firefox 133

Operating system and its version

Not relevant

PDF.js version

master (308ca2a)

Is the bug present in the latest PDF.js version?

Yes

Is a browser extension

No

Steps to reproduce the problem

1. Open https://www.gtt.to.it/cms/risorse/urbana/mappa/mapparete.pdf
2. Set the zoom to 200%

What is the expected behavior?

While PDF.js is rendering pages, it shows a little loading spinner, that disappears once the page is done rendering.

The steps above should show a loading spinner.

What went wrong?

The loading spinner is added to the document, however it's added to the center of the page. The center of the page is outside of the browser viewport, so the spinner is not visible.

Link to a viewer

No response

Additional context

I noticed this while working on #19128. The spinner should be in the middle of the visibleArea computed in that PR.

[Snuffleupagus]

The spinner in the pageNumber-input (on the toolbar) is however always visible, which makes this a lot less problematical (and possibly even a non-issue).

[nicolo-ribaudo]

Not on Firefox for Android, since the toolbar is not shown there :)