rendererTransitionTimeoutMs

A renderer transition happens when the activeRenderer changes, or a refresh() call requires the activeRenderer to re-layout its content. Normally the renderer transition will start when visible content has finished rendering.

This option controls the maximum time to wait for visible content to render before starting the renderer transition anyway. Setting this to 0 will cause the renderer transition to start immediately and will cause loaders to show until pages have rendered.

To change the loader animation you can use ReaderView.setContentOnLoading().