EP0231061A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Improvements in or relating to graphic display systems
Assignee: International Business Machines Corp
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Filing: 1987-01-08
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Granted: —
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Expires: 2007-01-08
Abstract
Abstract A colour graphics display having a read/write control system for a buffer memory therein provides Line-on-Line and Underpaint mode operation, if selected and enabled, by reading the contents of a frame buffer storage location for which new pixel data is being provided, comparing those contents with data representing a display background characteristic or colour, and if the result of the comparison is positive, storing the new pixel data to the frame buffer storage location. If the result of the comparison is negative, a selected data value different from the new pixel data is stored to the frame buffer storage location.
Inventors
- 👤 Matthew Elsner
- 👤 Yoshio Iida
- 👤 Edward Yuman Kwong
- 👤 Omar Mahmoud Rahim
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 19:01
CPC Classifications
G; G09; G09G; G09G5/00; G09G5/36; G09G5/39; G09G5/393; G09G5/02; G09G5/026
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
170 words
A computer display system having a frame buffer which stores pixel data for display pixels at corresponding storage locations for each pixel and capable, inherently or when so enabled, of incorporating new data in an existing display under a selected one of plural modes, say, overwrite and underwrite or line-on-line, wherein the update processing is performed locally at the frame buffer in response to new pixel data for a particular storage location thereof by: reading the contents of a frame buffer storage location for which new pixel data is being provided; comparing the results of the data step of reading with data representing a display background characteristic; and if the result of the step of comparing is positive, storing the new pixel data to the frame buffer storage location; ELSE if the result of the step of comparing is negative and a mode is selected, storing a selected data value different, in a manner determined by the mode selected, from the new pixel data to the frame buffer storage location.
Claim 2
Dependent Claim
170 words
A computer display system having a frame buffer which stores pixel data for display pixels at corresponding storage locations for each pixel and capable, inherently or when so enabled, of incorporating new data in an existing display under a selected one of plural modes, say, overwrite and underwrite or line-on-line, wherein the update processing is performed locally at the frame buffer in response to new pixel data for a particular storage location thereof by: reading the contents of a frame buffer storage location for which new pixel data is being provided; comparing the results of the data step of reading with data representing a display background characteristic; and if the result of the step of comparing is positive, storing the new pixel data to the frame buffer storage location; ELSE if the result of the step of comparing is negative and a mode is selected, storing a selected data value different, in a manner determined by the mode selected, from the new pixel data to the frame buffer storage location.
Claim 3
Dependent Claim
57 words
A method as claimed in Claim 1 wherein the step of storing a selected data value different from the new pixel data comprises restoring the results of the step of reading, back to the frame buffer storage location, or leaving the buffer store location unchanged, if the store construction so permits, when "underpaint" is the mode selected.
Claim 4
Dependent Claim
48 words
A method as claimed in Claim 1 wherein the step of storing a selected data value different from the new data value comprises storing selected pixel data different from either the new pixel data or the results of the step of reading, to the frame buffer storage location.
Claim 5
Independent Claim
29 words
A method as claimed in any preceding claims including selectively masking mode selection for storage locations whereby no new data values are introduced into the display at such locations.
Claim 6
Dependent Claim
144 words
A computer display system having a frame buffer which stores pixel data for display pixels at corresponding storage locations for each pixel, having the capability of modifying, in a selectable mode, the frame buffer in response to new pixel data for those storage locations, comprising: means for reading the contents of a frame buffer storage location for which new pixel data is being provided; means for comparing the results of the step of reading with data representing a display background characteristic; means, responsive to the means for comparing, for storing the new pixel data to the frame buffer storage location, if the result of a comparison operation is positive; and means, responsive to the means for comparing, for storing a selected data value different from the new pixel data to the frame buffer storage location, if the result of a comparison operation is negative.
Claim 7
Dependent Claim
144 words
A computer display system having a frame buffer which stores pixel data for display pixels at corresponding storage locations for each pixel, having the capability of modifying, in a selectable mode, the frame buffer in response to new pixel data for those storage locations, comprising: means for reading the contents of a frame buffer storage location for which new pixel data is being provided; means for comparing the results of the step of reading with data representing a display background characteristic; means, responsive to the means for comparing, for storing the new pixel data to the frame buffer storage location, if the result of a comparison operation is positive; and means, responsive to the means for comparing, for storing a selected data value different from the new pixel data to the frame buffer storage location, if the result of a comparison operation is negative.
Claim 8
Dependent Claim
20 words
A computer display system as claimed in Claim 5 including mask register means settable to permit/inhibit mode determined display modification.
References Cited (Backward Citations)
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