API Reference > imodeljs-frontend > Views > Viewport > onRender onRender Readonly onRender: BeEvent<(vp: Viewport) => void> = ... Called when the visible contents of the viewport are redrawn. note Due to the frequency of this event, avoid performing expensive work inside event listeners. Defined in core/frontend/src/Viewport.ts Line 2224 Last Updated: 12 June, 2024