Raster scan display apparatus for dynamically viewing image elements stored in a random access memory array

A computer graphics display system comprising:

• video signal generating means for developing a raster signal including a plurality of scan lines each divided into a plurality of equal signal periods containing information corresponding to picture elements of an image to be displayed;
• hashing means for periodically disabling the output of said generating means so as to blank said raster signal during a predetermined portion of each said signal period;
• and
• video display means responsive to the periodically blanked raster signal and operative to develop a visual image corresponding thereto such that the said blanking of said raster signal causes the displayed image to appear to have a matt background.

A computer graphics display system for displaying in raster fashion an image comprised of an n .times. m array of picture elements, comprising:

• raster memory means including a data storage array having N rows and M columns of data storage sites;
• means for providing a selectable first origin address signal for designating the origin site of a first n .times. m array of storage sites in said raster memory means, where n is an integer less than N and m is an integer less than M;
• clock generating means for generating first, second and third clock signals, said first clock signal including Zm signal pulses for each signal pulse of said second clock signal, and said second clock signal including Zn signal pulses for each signal pulse of said third clock signal, where Z is any positive integer;
• means responsive to said first origin address signal and said first, second and third clock signals and operative to start at the origin site of said first n .times. m array and read out data from m storage sites in each of the n rows of said first n .times. m array;
• raster means for developing a raster scan signal from the data read out of said first n .times. m array;
• and
• display means responsive to said raster scan signal and operative to display an image corresponding to the data contained in said first n .times. m array.

A computer graphics system for displaying in an n .times. m array of picture elements a magnified image of data contained in a zoomed portion of an N .times. M memory array, comprising:

• raster memory means including a data storage array having N rows and M columns of data storage sites;
• means for providing an origin address signal for designating the origin site of an n/Z .times. m/Z array of storage sites in said raster memory means where Z is an integer, n/Z is an integer equal to or less than N, and m/Z is an integer equal to or less than M;
• clock generating means for generating first, second and third clock signals, said first clock signal including m signal pulses for each signal pulse of said second clock signal, and said second clock signal including n signal pulses for each signal pulse of said third clock signal;
• means for generating a zoom signal having a zoom factor of Z;
• means responsive to said origin address signal, said first, second and third clock signals, and said zoom signal and operative to start at the origin site of said n/Z .times. m/Z array and read out data from m/Z storage sites in each row thereof, the data contained in each site in each row being read out Z consecutive times before the data contained in the next adjacent site is read out, and the data read out of each row being repeated Z consecutive times before data is read out from the next row;
• raster means for developing a raster scan signal from the data read out;
• and
• display means responsive to said raster scan signal and operative to display an image corresponding to the data contained in said n/Z .times. m/Z array.

A computer graphics display system comprising:

• raster memory means including a data storage array having N rows and M columns of data storage sites;
• first means for providing a first origin address signal for designating the origin site of a first r .times. m array of storage sites in said raster memory means;
• second means for providing a second origin address signal for designating the origin site of a second s .times. m array of storage sites in said raster memory means, where n is an integer equal to or less than N, m is an integer equal to or less than M, and r and s are integers selected to satisfy the equation r .times. s = n;
• clock generating means for generating first, second and third raster clock signals, said first raster clock signal including m signal pulses for each signal pulse of said second raster clock signal, and said second clock signal including n signal pulses for each signal pulse of said third clock signal;
• means responsive to said first origin address signal, said second origin address signal and said first, second and third raster clock signals and operative to start at the origin site of said first array and to read out data from m storage sites in each of the r rows thereof and then start at the origin site of said second array and read out data from m storage sites in each of the s rows thereof;
• raster means for developing a raster scan signal from the data read out from said first and second arrays;
• and
• display means responsive to said raster scan signal and operative to display a split image containing the data from both said first array and said second array.

A computer graphics display system comprising:

• raster memory means including a data storage array having N rows and M columns of data storage sites;
• first means for providing a first origin address signal for designating the origin site of a first n .times. u array of storage sites in said raster memory means;
• second means for providing a second origin address signal for designating the origin site of a second n .times. v array of storage sites in said raster memory means, where n is an integer equal to or less than N, m is an integer equal to or less than M, and u and v are integers selected to satisfy the equation u + v = m;
• clock generating means for generating first, second and third raster clock signals, said first raster clock signal including m signal pulses for each signal pulse of said second raster clock signal, and said second clock signal including n signal pulses for each signal pulse of said third clock signal;
• means responsive to said first origin address signal, said second origin address signal and said first, second and third raster clock signals and operative to start at the origin site of said first array and read out data from u storage sites in the first row of said first array and then read out data from v storage sites in the first row of said second array followed by a series of similar split readouts of data from the next n - 1 rows of said first and second arrays;
• raster means for developing a raster scan signal from the data read out from said first and second arrays;
• and
• display means responsive to said raster scan signal and operative to display a split image containing the data from both said first array and said second array.

A computer graphics display system for use in association with a host computer to provide a visual display of graphics information contained therein, comprising:

• a data bus;
• an address bus;
• display means for developing a visible image corresponding to video signals input thereto;
• channel adapter means for providing an interface for communicating information including bits of graphics data between the host computer and said data bus and said address bus;
• system control means communicatively coupled to said data bus and said address bus and operative to generate first and second control signals;
• raster memory means including an array of N rows and M columns of storage sites each capable of storing a bit of graphics data corresponding to a picture element of a graphics image to be formed by said display means;
• raster memory control means communicatively coupled to said address bus, said data bus, said raster memory means and said system control means, said raster memory control means being responsive to said first control signal and operative to cause bits of graphics data input from the host computer to be stored in said raster memory means, said raster memory control means including means for inputting data into selected ones of said storage sites and for causing such data input to sites presently occupied by other data to be logically exclusive ORed;
• and
• video control means communicatively coupled to said address bus, said data bus, said raster memory means, said display means, and said system control means, said video control means being responsive to said second control signal and operative to read out in raster fashion data stored in said raster memory means and to use such data to generate a video signal for input to said display means.

A computer graphics display system for use in association with a host computer to provide a visual display of graphics information contained therein, comprising:

• a data bus;
• an address bus;
• display means for developing a visible image corresponding to video signals input thereto;
• channel adapter means for providing an interface for communicating information including bits of graphics data between the host computer and said data bus and said address bus;
• system control means communicatively coupled to said data bus and said address bus and operative to generate first and second control signals;
• raster memory means including an array of N rows and M columns of storage sites each capable of storing a bit of graphics data corresponding to a picture element of a graphics image to be formed by said display means;
• raster memory control means communicatively coupled to said address bus, said data bus, said raster memory means and said system control means, said raster memory control means being responsive to said first control signal and operative to cause bits of graphics data input from the host computer to be stored in said raster memory means, said raster memory control means including skip pattern control means for periodically inhibiting a storage operation in a predetermined manner so as to prevent certain bits of the data from being stored in said raster memory means, said skip pattern control means including a skip pattern memory for storing a plurality of predetermined skip pattern commands, and logic means controlled by said system control means and operative to select one of said skip pattern commands and to generate a first signal in accordance therewith for periodically inhibiting said storage operation, said skip pattern control means further including modulo arithmetic logic means for generating a second signal for periodically inhibiting said storage operation;
• and
• video control means communicatively coupled to said address bus, said data bus, said raster memory means, said display means, and said system control means, said video control means being responsive to said second control signal and operative to read out in raster fashion data stored in said raster memory means and to use such data to generate a video signal for input to said display means.