Systems, methods, and apparatus, including computer program products, for abstracting rendering logic and automatically generating platform-specific renderers from the abstracted rendering logic for multiple platforms. A platform-independent description of rendering logic for a control is specified. The platform-independent description is used to generate a platform-specific renderer for the control. The platform-specific renderer is operable to be executed on a specific platform to produce code that can be used in rendering the control on a client computer. Some implementations enable code for platform-specific renderers to be generated automatically based on centrally defined rendering logic. Rendering logic can thus be modified once and used to automatically update code and libraries for platform-specific renderers on multiple platforms.