Use of inversions in the near realtime control of selected functions in interactive buffered raster displays

• US 4,521,770 A
• Filed: 08/30/1982
• Issued: 06/04/1985
• Est. Priority Date: 08/30/1982
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Rhyne, James R.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/412,481
• Time in Patent Office: 1,009 Days
• Field of Search: 340/703, 340/701, 340/707, 340/721, 340/723, 340/724, 340/734, 340/747, 340/799, 364/521, 364/522
• US Class Current: 345/589
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables

Abstract

If object identity is written into pixel locations of the refresh buffer portion of a raster-driven display as objects are drawn or amended, and if such object identity is used to index color maps and tree-linked lists of multiple object displays, then editing functions, such as correlation and echoing, color mixing, and selective erasure, at the display level can be invoked and executed with a minimum of reprocessing of the display list at the host level.

Claims

1. A method for editing a display of multicolored objects exhibited by an interactive refresh buffer raster driven display system comprising the steps of:

(a) forming a first concordance of display position and object identity and storing said first concordance in the refresh buffer;

(b) forming a second concordance of object identity and color attributes and storing said second concordance in auxiliary memory;

(c) position selecting at least one display object and specifying an editing function; and

(d) executing the editing function by way of dynamic alteration of those attributes in the second concordance accessed through the position selection and object identity of the first concordance.

2. A method according to claims 1 or 3, wherein the editing function comprises selective erasure by way of removal of one or more overlapping color objects of dissimilar values, and further wherein the second concordance includes a tree structured linked list, each list entry being indexed by the object identity in the order in which drawn, each list entry includes the object erasure status, and the identity of the most and least recently drawn objects overlapping of the object indexing the entry, and still further wherein:

the position selecting and function specifying step includes the designation of the object to be erased;

the editing function execution step of selective erasure includes;

ascertaining whether an erasable object intersects any other drawn object and, if so, whether such intersection is with an object drawn prior or subsequent to the drawing of the erasable object;

and in the alternative either;

(a) deleting the object identity from counterpart display position entries in the first concordance if there be no overlap between erasable and other drawn objects;

(b) marking the erasable object as being deleted in the status field of the list indexed by its object identity if there be overlap with a subsequently drawn object;

or

(c) restoring the identity in counterpart display position entries in the first concordance of the most recently drawn object as expressed in the status field of the list indexed by the erasable object if there be overlap with a previously drawn object.

3. A method according to claim 1, wherein the position selecting and function specifying step includes selecting a function from the function set consisting of correlation and echoing, object mixing, and selective erasure.

4. A method for correlating and echoing selective multicolored objects within a display exhibited by an interactive refresh buffer raster driven display system comprising the steps of:

(a) forming a first concordance of display position and object identity and storing said first concordance in the refresh buffer;

(b) forming a second concordance of object identity and color attributes and storing said second concordance in auxiliary memory, said color attributes includes primary, secondary, and currently displayed color values and correlation markings, if any;

(c) position selecting at least one display object and instantaneously marking said object; and

(d) comparing the instantaneous and any previously recorded markings;

upon detection of a noncorrespondence therebetween, turning off any previously initiated echo by assigning the primary to the currently displayed object color value, recording the instantaneous markings, and turning the new echo on by assigning a secondary to the currently displayed object color value; and

upon detection of a correspondence therebetween, inhibiting change of the currently displayed object color value.

5. An apparatus for display editing comprising:

raster driven display means;

a buffer for storing a display position-object identity image;

a table of attributes indexed by object identity;

means for refreshing the raster display by reading the buffer content in serial order, ascertaining the counterpart attributes from the table and modulating the display means accordingly;

an intercoupling stored program controlled processor for executing graphical orders; and

means for externally interrupting said processor and for position selecting at least one displayed object and for designating an editing function to be performed thereon.

6. A method for color mixing by specification of an object intersection and overlap of colored objects within a display exhibited by an interactive refresh buffer raster driven display system, comprising the steps of:

(a) forming a first concordance of display position and object identity, and storing said first concordance in the refresh buffer;

(b) forming a second concordance including a tree structured linked list, each list entry being indexed by object identity in the order in which drawn, each list entry including a primary, secondary, and currently displayed color value, an invertible color mixing function, and identification of overlapped objects, and storing said second concordance in auxiliary memory;

(c) position selecting at least one display object and instantaneously marking said object; and

(d) accessing the first concordance to ascertain whether the location is empty or whether it is occupied by a previously drawn object--if unoccupied, the new object identity is written into that display buffer location--if occupied, accessing the second concordance indexed by the object identity obtained from the first concordance, upon the counterpart listing in the second concordance showing no overlap, assigning the currently displayed color value of said object to a value determined by a mixing function and the object primary color value;

upon the counterpart listing in the second concordance showing overlap, inhibiting the change of the currently displayed color value.

7. A method for selective erasure of one or more overlapping color objects of dissimilar value within a display exhibited by an interactive refresh buffer raster-driven display system, comprising the steps of:

(a) forming a first concordance of display position and object identity, and storing said first concordance in the refresh buffer;

(b) forming and storing in auxiliary memory a second concordance obtained from a tree-structured linked list, each list entry being indexed by the object identity in the order in which drawn in the refresh buffer, each list entry includes the object erasure status, and the identity of the most and least recently drawn objects overlapping the object indexing the entry;

(c) position selecting at least one display object and instantaneously marking said object for erasure; and

(d) ascertaining whether the marked erasable object intersects any other drawn object, and if so, whether such intersection is with an object drawn prior or subsequent to the drawing of the erasable object; and

in the alternative either;

(1) deleting the object identity from the counterpart display position entries in the first concordance if there be no overlap between erasable and other drawn objects;

(2) marking the erasable object as being deleted in the status field of the list indexed by its object identity if there be overlap with a subsequently drawn object;

or

(3) restoring the identity in the counterpart display position entries in the first concordance of the most recently drawn object as expressed in the status field of the list indexed by the erasable object if there be overlap with a previously drawn object.