Patent EP0278526A2 successfully refreshed from Google Patents.
EP0278526A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Graphics diplay controller having clipping function
Assignee: NEC Corp
•
Filing: 1988-02-15
•
Granted: —
•
Expires: 2008-02-15
Abstract
Abstract A graphics display controller is disclosed. This controller has a function of transferring figure data of a source area to a destination area having a portion contained in a drawing-enable area defined by a clipping rectangle having a diagonal line define by first and second coordinate data. The coordinate data of each word in the destination area is compared with the first and second coordinate data to detect whether or not each word of the destination area is contained in the drawing-enable area. First information is generated in response to a comparison result, which designates bit or bits whose data are allowed to be rewritten in each word of the destination area. Second information is generated in response to a position of the word of the destination area, which designates bit or bits whose data are allowed to be rewritten in the associated word of the destination area. The data of the bit of bits designated by both of the first and second information are rewritten with the figure data. Only the portion of the destination area contained in the drawing-enable area is thus rewritten with the figure data.
Inventors
- 👤 Mitsurou C/O Nec Corporation Ohuchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 15:43
CPC Classifications
G; G09; G09G; G09G5/00; G09G5/36; G09G5/39; G09G5/393; G06; G06T; G06T15/00; G06T15/10; G06T15/30
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
202 words
A graphics display controller having a function of transferring figure data to a destination area including a portion contained in a drawing-enable area defined by a clipping rectangle having a diagonal line defined by first and second coordinate data, said controller comprising means for storing third coordinate data responsive to said first coordinate data and fourth coordinate data responsive to said second coordinate data, means for comparing coordinate data designating a predetermined bit of each word of said destination area with said third and fourth coordinate data to detect whether or not at least one bit of each word of said destination area is in said drawing-enable area, means responsive to a comparison result from said comparing means for generating first information designating bit or bits whose data are allowed to be rewritten in each word of said destination area, means responsive to a position of each word of said destination area for generating second information designating bit or bits whose data are allowed to be rewritten in each word of said destination area, and means for writing the figure data into the bit or bits designated by both of said first and second information in each word of said destination area.
Claim 2
Dependent Claim
202 words
A graphics display controller having a function of transferring figure data to a destination area including a portion contained in a drawing-enable area defined by a clipping rectangle having a diagonal line defined by first and second coordinate data, said controller comprising means for storing third coordinate data responsive to said first coordinate data and fourth coordinate data responsive to said second coordinate data, means for comparing coordinate data designating a predetermined bit of each word of said destination area with said third and fourth coordinate data to detect whether or not at least one bit of each word of said destination area is in said drawing-enable area, means responsive to a comparison result from said comparing means for generating first information designating bit or bits whose data are allowed to be rewritten in each word of said destination area, means responsive to a position of each word of said destination area for generating second information designating bit or bits whose data are allowed to be rewritten in each word of said destination area, and means for writing the figure data into the bit or bits designated by both of said first and second information in each word of said destination area.
Claim 3
Dependent Claim
48 words
The controller as claimed in claim 1, wherein said third coordinate data designates a starting bit of a word having a bit designated by said first coordinate data and said fourth data designates a starting bit of a word having a bit designated by said second coordinate data.
Claim 4
Dependent Claim
49 words
The controller as claimed in claim 1, wherein said first information designates at least one bit of the word of the destination area which is contained in said drawing-enable area, said first information designating no bit when the word of the destination are is out of said drawing-enable area.
Claim 5
Dependent Claim
18 words
The controller as claimed in claim 1, said first and second information are generated by a mask ROM.
Claim 6
Dependent Claim
209 words
A processor comprising a display memory including a plurality of words each consisting of a plurality of bits, each of said bits having individual coordinate data on a display screen, means for producing the coordinate data of a predetermined bit of a word to be controlled, means for storing first and second coordinate data which define a diagonal line on said display screen, said diagonal line defining a rectangular area on said display screen, means for comparing said coordinate data of said predetermined bit of said word to be controlled with said first and second coordinate data to detect that said word to be controlled is inside or outside of said rectangular area or contains a boundary of said rectangular area, means responsive to a comparison result from said comparing means for generating first mask information determinating which bit of said word to be controlled is changed, means responsive to figure data to be drawn on said display screen for generating second mask information determining which bit of said word to be controlled is changed, and means responsive to said first and second mask information for writing said figure data into the bit or bits of said word to be controlled designated by said first and second mask information.
Claim 7
Dependent Claim
209 words
A processor comprising a display memory including a plurality of words each consisting of a plurality of bits, each of said bits having individual coordinate data on a display screen, means for producing the coordinate data of a predetermined bit of a word to be controlled, means for storing first and second coordinate data which define a diagonal line on said display screen, said diagonal line defining a rectangular area on said display screen, means for comparing said coordinate data of said predetermined bit of said word to be controlled with said first and second coordinate data to detect that said word to be controlled is inside or outside of said rectangular area or contains a boundary of said rectangular area, means responsive to a comparison result from said comparing means for generating first mask information determinating which bit of said word to be controlled is changed, means responsive to figure data to be drawn on said display screen for generating second mask information determining which bit of said word to be controlled is changed, and means responsive to said first and second mask information for writing said figure data into the bit or bits of said word to be controlled designated by said first and second mask information.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.