Graphics data processor with window checking for determining whe

Details Graphics data processor with window checking for determining whe Graphics data processor with window checking for determining whe

1990-12-20

1991-12-31

Herndon, Heather R.

C06F 1562

Patent

active

050776789

ABSTRACT:
A graphics data processor which includes the capability of determining whether a defined pixel location in a graphics display is within a window in an X Y coordinate system. The respective X and Y coordinates of the selected pixel are separately compared with the window limits. The window limits are preferable expressed as the X and Y coordinates of two diagonally opposite vertexes of a rectangular window. The results of this comparison are preferably available in two forms. In a first embodiment a single data processing instruction enables the generation of a digital data word which indicates the relation of the pixel to the window. This digital word includes a separate indication of the relationship of the pixel to the vertical and horizontal window limits. This indication can be used to generate a "trivial rejection" in determining whether a line or line segment passes through the window by ANDing the results for two points on the line. In a second embodiment the window compare capability is employed to determine whether or not a destination pixel is within the window. This is useful in array move instructions in which an entire array of pixels is moved to a location in the display. The array move may be aborted if a window violation is found or the move may be modified to plot to the display only those pixels within the window. This capability enables saving a great deal of time in graphics applications in which windows are employed by reducing the overhead needed for window determinations.

REFERENCES:
patent: 4257044 (1981-03-01), Fukuoka
patent: 4412296 (1983-10-01), Taylor
patent: 4481594 (1984-11-01), Staggs et al.
patent: 4495491 (1985-01-01), Postl
patent: 4598384 (1986-07-01), Shaw et al.
patent: 4779210 (1988-10-01), Katsura et al.
Electronic Design, "CRT Chip Controls Bit-Mapped Graphics and Alphanumerics", Yonezawa et al., Jun. 14, 1984, pp. 247-256.
First Microcomputer Engineering Dept. Musashi Works, Microcomputer Technical Marketing Dept. Semiconductor IC Division Hitachi Ltd., "HD63484 ACRTC".
Advanced CRT Controller Revision 2.0 7/15/84, pp. Bi, B35, B125, B159, B160, B161, B162, B163, B164, B165, B166, B282, B283.
First Microcomputer Engineering Dept. Musashi Works, Microcomputer Technical Marketing Dept. Semiconductor IC Division Hitashi Ltd., "Introduction of HD63484 ACRTC REV O July 23, 1984", pp. A1, A6, A13, A25, A29.
Foley, James D. and Van Dam, Andrias, Fundamentals of Interactive Computer Graphics, 1982, pp. 146-149.

Affiliated with

Also associated with

Rating

Graphics data processor with window checking for determining whe does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Graphics data processor with window checking for determining whe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Graphics data processor with window checking for determining whe will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1514530