US RE31,200 E · Raster scan display apparatus for dynamically viewing image elements stored in a random access memory array

Abstract

A computer graphics display system including random access raster memory for storing data to be displayed, a raster memory control unit for writing data into the raster memory, a video control unit for causing such information to be displayed on a CRT display screen, a micro control unit for controlling the function and timing of the raster memory control unit and the video control unit, and a computer adapter for facilitating data exchange between the micro control unit and a host computer. The displayed image can have extremely high complexity with essentially no problem of display flicker. Zoom and pan features allow the use of a very complex stored image in a flexible manner, and a split-screen technique enables an operator to work on a very complex picture at a detail level while still having an overview of the total picture, or any portion thereof, simultaneously presented before him. The split-screen feature also allows the simultaneous display of alphanumeric messages such as prompts, menus, or X-Y readouts added to the graphics display and a small area of the raster memory is usually reserved for this purpose. An XOR feature allows a selective erase that restores lines crossing or concurrent with erased lines. The XOR feature permits part of the drawing to be moved or "dragged" into place without erasing other parts of the drawing.

Claims21

Dependent claims

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;
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 any selected block of n rows and m columns of said storage sites, where n is an integer less than N and m is an integer less than M, and to use such data to generate a video signal for input to said display means whereby said display means is caused to display an image comprised of picture elements corresponding to the data obtained in the selected block of
storage sites.] 2. A computer graphics display system [as recited in claim 1 wherein said video control means includes,] 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;
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 any selected block of n rows and m columns of said storage sites, where n is an integer less than N and m is an integer less than M, and to use such data to generate a video signal for input to said display means whereby said display means is caused to display an image comprised of picture elements corresponding to the data obtained in the selected block of storage sites;
said video memory control means including:
a first control memory for storing a first set of readout control instructions received from said system control means;
a second control memory for storing a second set of readout control instructions received from said system control means;
readout means for reading out bits of graphics data stored in said raster memory means;
and
1ogic means for causing said readout means to read out data stored in a first selected block of storage sites of said raster memory means under control of said first set of instructions and to read out data stored in a second selected block of storage sites of said raster memory means under control of said second set of instructions, the data read out of said first and second blocks of storage sites being included in said video signal and said display means being caused to simultaneously display a first image corresponding to the data from said first block and a second
image corresponding to the data from said second block. 3. A computer graphics display system as recited in claim 2 wherein said video control means further includes,
cursor control logic for generating a cursor signal;
and
video mixer means for mixing said cursor signal and the data from said first and second blocks to develop said video signal.

24 more elements

[4. A computer graphics display system as recited in claim 1 wherein said video control means includes zoom control logic for controlling the number of times each bit of data is to be consecutively read out of said raster memory means by said readout means whereby data read out a first number of times will be displayed at a first scale and data read out a second number of times will

be displayed at a second scale different from said first scale.] 5. A computer graphics display system [as recited in claim 1 wherein said video control means includes,] 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;
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 any selected block of n rows and m columns of said storage sites, where n is an integer less than N and m is an integer less than M, and to use such data to generate a video signal for input to said display means whereby said display means is caused to display an image comprised of picture elements corresponding to the data obtained in the selected block of storage sites;
said video control means including:
grid generator means for generating grid signals for display by said display means;
and
video mixer means for mixing said grid signals with the data read out of said selected block to develop said video signal whereby the displayed image includes a background grid having a predetermined positional
relationship to the displayed graphics data. 6. A computer graphics display system [as recited in claim 1 wherein said video control means includes,] 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;
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 any selected block of n rows and m columns of said storage sites, where n is an integer less than N and m is an integer less than M, and to use such data to generate a video signal for input to said display means whereby said display means is caused to display an image comprised of picture elements corresponding to the data obtained in the selected block of storage sites;
said video control means including:
1ogic means for enabling the boundaries of said block of storage sites to be incrementally changed so as to cause the corresponding display to
appear to pan across the raster memory means. 7. A computer graphics display system as recited in claim 6 wherein said system control means includes means for limiting the area of said raster memory means over
which said boundaries may be incrementally changed. 8. A computer graphics display system as recited in claim 2 wherein said logic means includes ;
first means for determining when all data from said first block has been read out, [and] second means, cooperating with said first means, for causing said system control means to load a third set of read out control instructions into said first control memory , said logic means causing said readout means to read out data stored in a third selected block of storage sites of said raster memory means under control of said third set of instructions, and [for determining] third means, operative when all data from [a] said third block of storage sites has been read out, [and] for causing said system control means to reload said first set of control instructions back into said first control memory, said logic means thus causing said display means to simultaneously display first, second and third images corresponding to the first, second and third blocks of data.
. A computer graphics display system [as recited in claim 1 wherein said raster memory control means includes] 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;
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 any selected block of n rows and m columns of said storage sites, where n is an integer less than N and m is an integer less than M, and to use such data to generate a video signal for input to said display means whereby said display means is caused to display an image comprised of picture elements corresponding to the data obtained in the selected block of storage sites;
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.

36 more elements

[12. A computer graphics display system as recited in claim 1 wherein said raster memory control means includes zig-zag control logic for causing a block of data to be read into said raster memory means in a predetermined zig-zag pattern defined by a single set of coordinate points identifying one corner of the block of data.]

. A computer graphics display system [as recited in claim 1 wherein said raster memory control means includes] 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;
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 any selected block of n rows and m columns of said storage sites, where n is an integer less than N and m is an integer less than M, and to use such data to generate a video signal for input to said display means whereby said display means is caused to display an image comprised of picture elements corresponding to the data obtained in the selected block of storage sites;
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 graphics data appearing on said data bus from being stored in said raster memory
means. 14. A computer graphics display system as recited in claim 13 wherein said skip pattern control means includes 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. 15. A computer graphics display system as recited in claim 14 wherein said skip pattern control means further includes modulo arithmetic logic means for generating a second signal for perodically inhibiting said storage
operation. 16. A computer graphics display system [as recited in claim 1 wherein said video control means includes] 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;
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 datastored in any selected block of n rows and m columns of said storage sites, where n is an integer less than N and m is an integer less than M, and to use such data to generate a video signal for input to said display means whereby said display means is caused to display an image comprised of picture elements corresponding to the data obtained in the selected block of storage sites;
said video control means including:
sync generator means for generating a hashing pulse train and [a dot clock generator] hashing logic means responsive to said hashing pulse train [and operative to cause] for causing said video signal to be pulsed on and off to cause the display to
appear to have a matt background. 17. 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 in 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.

27 more elements

[19. A computer graphics system as recited in claim 18 and further comprising:

means for providing a second origin address signal for designating the origin site of a second n.times.m array of storage sites in said raster memory means;
means responsive to said second origin address signal and said first, second and third clock signals and
operative to start at the origin site of said second n.times.m array and read out data from m storage sites in each of the n rows of said second n.times.m array;
and
wherein said raster means also develops another raster scan signal from the data read out of said second n.times.m array and said display means also responds to said other raster scan signal to display the data contained in
said second n.times.m array.] 20. A computer graphics display system [as recited in claim 19] 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;
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;
means for providing a second origin address signal for designating the origin site of a second n.times.m array of storage sites in said raster memory means;
means responsive to said second origin address signal and said first, second and third clock signals and operative to start at the origin site of said second n.times.m array and read out data from m storage sites in each of the n rows of said second n.times.m array;
wherein said raster means also develops another raster scan signal from the data read out of said second n.times.m array and said display means also responds to said other raster scan signal to display the data contained in said second n.times.m array;
and wherein the data in said second n.times.m array is read out and displayed at a time subsequent to the reading out and display of the data in said first n.times.m array and means are provided for synchronizing the change in display with said third clock signal so that no displayed image includes data from both said first
n.times.m array and said second n.times.m array. 21. A computer grahics display system as recited in claim 20 and further comprising:
means for providing a series of other origin address signals identifying other n.times.m arrays of storage sites located between said first and second n.times.m arrays;
means responsive to each of said origin address signals and said first, second and third clock signals and operative to sequentially start at the origin site of each of said series of address signals and read out data from m storage sides in each of the n rows of each such array;
and
means for generating a pan clock signal that is a multiple of said third clock signal for synchronizing the change in read out from one n.times.m array to the other so as to create in the resulting display an illusion of smooth panning from said first n.times.m array through said other
n.times.m arrays to said second n.times.m array. 22. A computer graphics display system as recited in claim 20 or 21 wherein each of the said n.times.m arrays respectively contains data relating to phased still graphics of a cartoon to be animated, and said system further includes means for cyclically reading out in a predetermined series the data from said arrays so as to create in the display an illusion of
animated cartoon motion. 23. A computer graphics display system as recited in claim 20 or 21 wherein each of the said n.times.m arrays respectively contains data at variance with the data of the other arrays, and said system further includes means for cyclically reading out in a predetermined series the data from said arrays so as to create the illusion of a continuously varying image.

20 more elements

[24. 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.] 25. A computer grahics display system [as recited in claim 24] 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;
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;
and wherein said means for providing an origin address signal is synchronized with said third clock signal and is capable of sequentially providing other origin address signals in synchronism with said third clock signal so as to cause the display made by said display
means to create the illusion of a panning of said data storage array. 26. 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. 27. 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-l 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. 28. A computer graphics display system [as recited in claim 18 and further comprising:] 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 or 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;
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;
means for generating a grid signal including a series of pulses occurring in a series of regular timed intervals;
and
means for synchronously mixing said grid signals with the data read out of said n.times.m array so that the displayed image includes a background grid which has a predetermined positional relationship to the data
contained in said data storage array. 29. A computer graphics display system [as recited in claim 24 and further including] 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;
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;
and means for selectively inhibiting the readout of data from each storage site for one or more of the Z consecutive readout operations, and for inhibiting the corresponding repeat readout of each row of data whereby a zoomed display of a plurality of adjacent storage sites containing data will be displayed as an array of spaced apart dots rather than as a solid area so as to provide a visually perceptible
separation of adjacent bits of data. 30. 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. 31. 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.

71 more elements

An apparatus for generating a graphics display having the illusion of smooth panning across an image represented by a plurality of discrete picture elements, said image being larger than that which can be displayed at one time on a video display device, comprising:

a memory device;
means for entering in the storage sites of said memory device a set of digital data corresponding to the discrete picture elements of said image, selected subsets of said digital data being readable from said memory to produce a corresponding raster signal displayable by said video display device;
specifying means for specifying a first particular portion of said memory storage sites, said first particular portion containing a first subset of digital data corresponding to a first part of said image, said first part being displayable at one time on said video display device;
first selecting means for selecting a second particular portion of said memory storage sites, said second particular portion containing a second subset of digital data corresponding to a different, second part of said image, said second part also being displayable at one time on said video display device;
second selecting means for selecting a plurality of other portions of said memory storage sites, said other portions each containing a respective other subset of digital data corresponding to other parts of said image, said other parts being situated at contiguous spaced intervals in said image between said first part and said second part, each of said other parts also being displayable at one time on said video display device;
read-out means for reading out digital data in raster fashion from said memory device and for providing said corresponding raster signal in response thereto;
control means, cooperating with said read-out means, said specifying, means and said first and second selecting means, for directing said read-out means initially to read out in raster fashion said first subset of digital data contained in said first portion to develop a first raster signal, then sequentially to read out the other subsets of digital data in each of said other portions to develop a series of other raster signals, then to read out in raster fashion the second subset of digital data contained in said second portion to develop a second raster signal;
and
display production means, connected to said read-out means, for using said first raster signal, said other raster signals, and said second raster signal in the order that they are developed to produce on said video display device a raster display of the data contained in the various selected portions such that the produced display creates the illusion of smooth panning across said image from said first part to said second part.

6 more elements

An apparatus for implementing smooth panning in a computer graphics display system of the type having a memory storing digital data corresponding to picture elements of an image that is larger than can be displayed at one time, and in which a subset of said stored digital data is read out from said memory and supplied to a video display device in raster fashion to produce on said device a display of the portion of said image represented by said data subset, each such data subset being specified by a corresponding origin address within said memory, comprising:

pan clock means for generating a pan clock signal that is synchronized with the frame rate of said video display device;
first means for specifying a first data subset representing that first position of said image at which panning is to begin;
second means for specifying a second data subset representing the second portion of said image at which is panning is to terminate;
third means for specifying data subsets representing closely, sequentially contiguous portions of said image intermediate said first and second portions;
and
read-out means, cooperating with said pan clock means and with said first, second and third means, for sequentially reading out from said memory said first, said group of intermediate, and said second data subsets in raster fashion for supply to said video display device to produce corresponding sequential displays of the portions of said image represented thereby, each such sequential readout being synchronized with said pan clock signal, whereby the resultant display has the illusion of smooth panning in which each successive video frame synchronized display represents a portion of said image that is closely contiguous to the preceeding display.

3 more elements

Dependencies are inferred from the claim text.

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

Life of this patent

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

Life of this patent

Abstract

Claims21