Browse Prior Art Database

Dynamic Window Viewport Relocation

IP.com Disclosure Number: IPCOM000086352D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Fritz, DH: AUTHOR

Abstract

This apparatus performs dynamic transformation and relocation of a window on an arbitrarily sized data segment to the screen coordinates of a fixed display surface, and provides scissoring to the viewport boundary on the display surface.

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Dynamic Window Viewport Relocation

This apparatus performs dynamic transformation and relocation of a window on an arbitrarily sized data segment to the screen coordinates of a fixed display surface, and provides scissoring to the viewport boundary on the display surface.

A data segment is a two-dimensional display space buffered in the display subsystem data segment storage buffer 10. Its size is independent of the capacity of the display surface 12. A window 14 is a rectangular portion of the data segment. A viewport 16 is a rectangular portion of the display surface 12, within which a portion of the data segment, a window, may be made visible.

The transformation registers 18 translates windows 14 to viewports 16. There is a set of registers for each row of the display surface 12 with one register 18 assigned to each viewport 16 intersecting that display row. Generation of the display proceeds left to right a row at a time, utilizing the transformation registers 18 as a level of indirect addressing into the data segment storage buffer 10. Blanks are generated between viewports 16.

Each transformation register 18 includes the following components: 0 Data segment storage buffer address 20, which is the buffer address corresponding to the left window boundary for the appropriate row of the window 14. 0 Display surface address 22, which is the display address corresponding to the left viewport boundary for the appropriate row on the display surface 12. 0 Count 24, ...