The material design project has created a standard set of icons that are freely available to use in any application. Integrating these clear, concise icons into your user interface adds simple-to-understand hints that are consistent with other applications and can alleviate the need for too much text in the resulting user interface. Shiny bundles the most commonly used icons in the materialdesign/icons package and they can be referenced by name through the API. To see the list of names and the icons, you can run the Shiny IconGallery example (pictured in the following screenshot):

The icons can be painted within a node.PaintBase() method by creating an iconvg.Rasterizer instance for node.PaintBaseContext and calling iconvg.Decode() for the icon reference (these icons are stored in the compact IconVG format). Examples of this code in action can be found later in the chapter (or in the Shiny example code).