At the heart of the R Graphics system lies a graphics engine. This defines a graphics vocabulary for R - a set of possible graphics operations like drawing a line, colouring in a polygon, or setting a clipping region. Graphics packages like 'ggplot2' allow users to describe a plot in terms of high-level concepts like geoms, scales, and aesthetics, but that high-level description has to be reduced to a set of graphics operations that the graphics engine can understand.

Unfortunately, the R graphics engine has a limited vocabulary. It can only draw simple shapes, it can only fill regions with solid colour, and it can only set rectangular clipping regions. This makes it hard (or impossible) for packages like 'ggplot2' to produce some types of graphical output because the graphics engine does not support several fundamental graphical operations.

This talk will describe recent work on the graphics engine that expands its vocabulary to include gradient fills, pattern fills, clipping paths, and masks.