By Tobias Isenberg
This paper presents an overview of the image-morphologic primitives used commonly in non-photorealistic rendering (NPR), a subdomain of computer graphics that is inspired by a long tradition of artistic and illustrative depiction. In particular, we survey NPR shading, stroke-based rendering, sparse line drawings, graftals, and area primitives. Such primitives usually cover larger regions on the canvas and often carry a meaning beyond the color of the image region they represent. This distinguishes them from the pixel as a primitive used in photorealistic rendering, which does not have any meaning aside from sampling the color of the image section it represents. We give examples to illustrate the individual techniques and briefly mention how they are tracked though the rendering process as well as represented in the final image.