Method for creating consistent bitmaps in message-driven environments

Abstract

Bit-mapped drawings are normally created by using the so-called 'Paint Editor' through the provided image primitives. A set of operation tools are also available for interactive manipulation of primitive objects. Window-based operating environments, such as the IBM OS/2 Presentation Manager, provide an Application Programming Interface to send messages to modules that actually carry out bitmap generation. We observed that this message-driven architecture can facilitate the 'capture and reapplication of user operations' for application programs. Therefore, it is possible to create a set of bit-mapped drawings that conform to certain properties through the same sequence of operations. Two applications are described in this paper. The first is the creation of fonts with a consistent typeface. The sequence of operations used in designing the typeface is automatically recorded. The user can then generate bitmaps of other characters with the same typeface by repeating the same sequence of operations. The second application is the generation of shadows of 3D objects. If a profile of an object is given, the shadow can be synthesized by bitmap manipulation primitives. When the same sequence of primitives is applied to different objects, shadows can be generated correctly.