Emulating Overlapping Windows on an Alphanumeric Display
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
IBM 3270 architecture display devices have the special characteristic that they require one character cell on the screen for each alphanumeric field attribute. Special algorithms for positioning the alphanumeric field attributes are therefore necessary in order to emulate overlapping windows or partitions on these devices. An algorithm is disclosed for positioning field attributes before and after alphanumeric fields which are clipped by window boundaries or overlapped by other windows. This algorithm is also extended for positioning field attributes around the alphanumeric cells which make up the borders of windows. When alphanumeric fields within an emulated partition or window are clipped or overlapped, it is necessary to generate extra field attributes around the visible part or viewport of the field.