toolbar.layout
Which toolbar to render. The trade is deliberate: the bar is shorter (64px against the ribbon's ~105px) but on a narrow container some tools end up behind More. The ribbon always costs a second row and always keeps every tool one tab away. None is correct for every host, which is why all three ship.
ToolbarLayout ('bar' | 'ribbon' | 'none' | 'rail')default 'bar'
Values
'bar'Default. One row of tools in labeled clusters. Under pressure it drops labels, then moves the lowest-priority tools into a More menu. Choose it when tools are used in short bursts and the document deserves the vertical space.'ribbon'A tab per group; the selected group's tools sit on a second row. Under pressure the tab strip scrolls and labels drop — a tool is never hidden. Choose it when users work in one mode at a time (mark up a document, then fill a form), or you cannot accept a tool becoming unreachable.'rail'The bar's tools down the left edge and the active tool's options down the right, the pages between; the top bar keeps the chrome. What a tablet gets by default (seelayout.tablet). Choose it when you want this arrangement on every screen but a phone.'none'No toolbar at all. The nav bar, panels and page area render as usual. For hosts building their own chrome and driving the SDK through the viewer API.
Example
layoutTypeScript
new PDFViewer(container, doc, { toolbar: { layout: 'ribbon' }, });