<aside> 🌐 https://mupdf.com/r/App-Design

</aside>

MuPDF App Design

This is a proposal for the design requirements of a new MuPDF mobile app.

MAIN UI

When you open the app, we should show a simple file chooser.

When opening a document either via “Open with…” in another app, or from inside our file chooser, we go directly to the document view mode. There should not be a separate ‘document preview’ mode like in SmartOffice – we’re a viewer not a document editor so this is just a needless confusing mode.

We should allow multiple documents to be open at the same time, so opening a document should launch a new activity rather than replacing the old one.

There should be a full screen ‘read only’ mode that you can toggle, which hides all the UI chrome and shows only the page contents. This can behave like the Kindle device and other e-readers: tapping on the left or right third of the screen goes back and forward a page (or vice versa in RTL mode), tapping on center of the screen brings the UI back. Hiding the UI could be done by a tap in the middle, or by hitting an icon in the toolbar, but should be quickly and trivially accessible.

In landscape mode, consider putting the UI controls and toolbars in a panel on the right (or left) side of the screen, to allow the biggest number of lines on the page to be seen. Toolbars at the top take a lot of vertical space, which is at a premium.

DISPLAY MODES

The app should have two main display modes:

In continuous scroll mode, the default zoom should be fit-to-width.

The page scrubber should be at the bottom, matching the same direction of swiping left/right.

In paged mode, the default zoom should be fit-to-page.

Paged mode need a toggle for right-to-left reading. This is used in RTL languages and also for manga comic books.

Optional:

Paged mode could have an option to show two pages spread side-by-side, showing facing pages. Flipping to the next/previous page would go to the next/previous spread. This facing mode would need a few more options if implemented: