The reader has one toolbar under the document and two buttons in its top right corner. Every control is an icon with a tooltip and no written label, so hover before you click. None of them change the publication itself: these are your viewing settings, and they start fresh each time you open the page.
Moving through the document
The centre of the toolbar is page navigation: previous and next, a box showing the page you are on, and first and last page buttons on desktop. The thin bar across the top of the document is a seek bar. Hover it to see which page you would land on, then click to jump there.
The contents button opens a side panel. It lists the document's bookmarks if the PDF has any, and a plain page list if it does not. The two buttons in that panel's header switch it between the list and a grid of thumbnails.
Arrow keys work in page-flip mode only. Left and up go back, right and down go forward, Home goes to the first page and End to the last. In continuous scroll they do nothing, because scrolling already does that job.
Changing the layout
Two buttons on the left cycle rather than toggle, so keep clicking to reach the setting you want. Their tooltips name the mode you will get next, not the one you are in.
- Spread cycles single page, two-page, and cover facing. Cover facing pairs pages the way a printed book does, with the cover on its own.
- View mode switches between page-flip and continuous scroll.
Next to them sit rotate clockwise, focus mode, which hides everything except the document, and presentation mode, which fills the screen and moves on the arrow keys or the space bar. Fullscreen is on the right, and a minimap button appears in the toolbar only while you are in fullscreen.
On desktop the reader opens in cover facing, page flip. On a screen 768 pixels wide or narrower it opens in continuous scroll, single page, and hides rotate, focus, presentation, first and last page, and the fit control.
Zoom
Zoom runs from 25% to 500% in steps of 25. Click the percentage between the two zoom buttons to return to 100% and fit the width. Double-clicking a page toggles between 100% and 200%. Once a page is wider or taller than the window, drag it to pan.
The fit button beside them also cycles: fit to page, fit to width, fit to height, then back to 100%.
Document info, print and download
The top right corner of the reader holds a print button and a Document Info button. Document Info reports the page count and whatever the PDF itself carries: title, author, creator, producer and creation date.
Print and download are the only two controls that check who you are. Both work if you hold an active UNI membership or you are the author. For everyone else they work only when the author allowed public downloads on that publication, which is true of very few of them, and the tooltip reads "UNI Membership required" instead. Downloading a publication covers that rule, and why the checkbox that sets it cannot currently be changed.
If the controls never appear
You have to be signed in to reach the reader at all, and the toolbar draws only once the pages have been rendered. "Preparing document pages", or a preview that is not available, means those pages are not ready yet: see When a publication says 'Preparing document pages' or 'Preview unavailable'.