WHAT IS CLAIMED IS :

1. In a graphics subsystem having framebuffer storage organized for storing signals specifying the pixels (x,y) of an X x Y raster framebuffer, said storage being sequentially addressable as a plurality of framebuffer pixel update arrays, the set of said update arrays tiling the framebuffer,

each said update array having a determined origin with respect to said framebuffer and

comprising storage sites for specifications of a plurality of contiguously positioned framebuffer pixels, each said storage site being specifiable by an offset with respect to said update array origin, the pixel specifications of a said update array being concurrently updatable in a parallel memory

transaction,

a method of selecting framebuffer pixels for drawing, comprising the steps:

(1) specifying a directed line with

respect to said framebuffer,

(2) accessing a said update array,

(3) concurrently for all pixel sites of said accessed array,

(a) evaluating the sidedness of the

framebuffer pixel whose specification is

stored at said pixel site with respect to

said directed line to derive a one-bit

discriminant signal for each said accessed array pixel site, and

(b) using a first value of said

discriminant signal to prevent writing to

said accessed array pixel site.

2. In a graphics subsystem having framebuffer storage organized for storing signals specifying the pixels (x,y) of an X x Y raster framebuffer, said storage being sequentially addressable as a plurality of framebuffer pixel update arrays, the set of said update arrays tiling the framebuffer,

each said update array having a determined origin with respect to said framebuffer and

comprising storage sites for specifications of a plurality of contiguously positioned framebuffer pixels, each said storage site being specifiable by an offset with respect to said update array origin, the pixel specifications of a said update array being concurrently updatable in a parallel memory

transaction,

a method of drawing a convex geometric figure to said framebuffer storage comprising the steps:

(1) specifying a figure to be drawn to

said framebuffer storage by specifying with

respect to said framebuffer a set of directed lines such that the segments of said lines

between their mutual intersections comprise the boundary of said figure, the directions of said lines being specified such that said segments perambulate said boundary in a single sense,

(2) accessing a said update array,

(3) concurrently for all pixel sites of said accessed array, concurrently for each

directed line of said set,

(a) evaluating the sidedness of the

framebuffer pixel whose specification is

stored at said pixel site with respect to

said directed line to derive a one-bit

discriminant signal for each said accessed array pixel site, and

(b) ANDing said discriminant signals for said set of directed lines to derive a result discriminant signal

(c) using a first value of said

result discriminant signal specifying outsidedness of the framebuffer pixel with respect to the figure to be drawn to

prevent writing to said accessed array

pixel site,

(4) repeating steps 1-3 for further arrays to tile said figure to be drawn.

3. In a graphics subsystem having framebuffer storage organized for storing signals specifying the pixels (x,y) of an X x Y raster framebuffer, said storage being sequentially addressable as a plurality of framebuffer pixel update arrays, the set of said update arrays tiling the framebuffer,

each said update array having a determined origin with respect to said framebuffer and

comprising storage sites for specifications of a plurality of contiguously positioned framebuffer pixels, each said storage site being specifiable by an offset with respect to said update array origin, the pixel specifications of a said update array being concurrently updatable in a parallel memory

transaction,

a method of drawing a geometric figure to said framebuffer comprising the steps:

(1) decomposing said figure to be drawn into a set of convex geometric figures,

(2) for each said convex geometric figure, specifying with respect to said framebuffer a set of directed lines such that the segments of said lines between their mutual intersections comprise the boundary of said figure, the

directions of said lines being specified such that said segments perambulate said boundary in a single sense,

(3) accessing a said update array, (4) concurrently for all pixel sites of said accessed array, concurrently for each

directed line of said set,

(a) evaluating the sidedness of the

framebuffer pixel whose specification is

stored at said pixel site with respect to

said directed line to derive a one-bit

discriminant signal for each said accessed array pixel site, and

(b) ANDing said discriminant signals for said set of directed lines to derive a result discriminant signal

(c) using a first value of said

result discriminant signal specifying

outsidedness of the framebuffer pixel with respect to the figure to be drawn to

prevent writing of the pixel specification stored at said accessed array pixel site,

(5) repeating steps 1-4 for further arrays to tile said convex geometric figure,

(6) repeating steps 1-5 for each said

convex geometric figure into which said figure to be drawn was decomposed.

4. In a graphics subsystem having framebuffer storage organized for storing signals specifying the pixels (x,y) of an X x Y raster framebuffer, said storage being sequentially addressable as a plurality of framebuffer pixel update arrays, the set of said update arrays tiling the framebuffer,

each said update array having a determined origin (origin_{x}, originy) with respect to said framebuffer and comprising storage sites for

specifications of a plurality of contiguously

positioned framebuffer pixels, each said storage site being specifiable by an offset (offset_{x}, offsety) with respect to said update array origin, the pixel specifications of a said update array being

concurrently updatable in a parallel memory

transaction,

a method of selecting framebuffer pixels for drawing, comprising,

(1) specifying a directed line with

respect to said framebuffer as (x_{l f} y-_{\} ) , (x ,

(2) calculating for said line

(χ_{2} - _{Xl}) ._{yι} - (y_{2} - y_{λ}) « ! = C,

(3) accessing a said update array,

(4) calculating for said line and array

(x_{2} - xi) • originy - (y_{2} - y ) -origin_{x} = B,

(5) concurrently for each pixel site of said accessed array,

(a) calculating (x_{2} - X_{j}) • offsety - (y2 - yi) * offset_{x} = A

(b) comparing A with (B + C) to

derive a one-bit discriminant signal for

each said accessed array pixel site, and

(c) using a first value of said

discriminant signal to prevent writing of

the pixel specification stored at said

accessed array pixel site.

5. In a graphics subsystem having framebuffer storage organized for storing signals specifying the pixels (x,y) of an X x Y raster framebuffer, said storage being sequentially addressable as a plurality of framebuffer pixel update arrays, the set of said update arrays tiling the framebuffer,

each said update array having a determined origin (origin_{x}, originy) with respect to said framebuffer and comprising storage sites for

specifications of a plurality of contiguously

positioned framebuffer pixels, each said storage site being specifiable by an offset (offset_{x}, offsety) with respect to said update array origin, the pixel specifications of a said update array being

concurrently updatable in a parallel memory

transaction,

a method of drawing a convex geometric figure to said framebuffer storage comprising the steps:

(1) specifying a figure to be drawn to

said framebuffer storage by specifying with

respect to said framebuffer a set of directed lines such that the segments of said lines

between their mutual intersections comprise the boundary of said figure, the directions of said lines being specified such that said segments perambulate said boundary in a single sense, specifying each line as ( ^, y^) , (X2, y2)

(2) for each directed line of said set, calculating (x_{2} - Xi) *yι - (y_{2} - yi) '- ι = C,

(3) accessing a said update array,

(4) calculating for said array and each said line (x - _{T}.) •originy - (y2^{_}yι) *origin_{x} =

B,

(5) concurrently for each said line,

concurrently for each said pixel site of said accessed array,

(a) calculating (x - Xi.) Offsety - (Y2 " Yl)*offset_{x} ^{«} A,

(b) comparing A with (B + C) to

derive a one-bit discriminant signal for

each said accessed array pixel site with

respect to a line,

(c) for each said pixel site, ANDing said discriminant signals for said set of

directed lines to derive a result

discriminant signal

(d) using a first value of said

result discriminant signal specifying

outsidedness of the framebuffer pixel with respect to the figure to be drawn to

prevent writing of the pixel specification stored at said accessed array pixel site, (6) repeating steps 1 - 5 for further

arrays to tile said figure to be drawn.

6. In a graphics subsystem having framebuffer storage organized for storing signals specifying the pixels (x,y) of an X x Y raster framebuffer, said storage being sequentially addressable as a plurality of framebuffer pixel update arrays, the set of update arrays tiling the framebuffer,

each said update array having a determined origin with respect to said framebuffer and

comprising storage sites for specifications of a plurality of contiguously positioned framebuffer pixels, each said storage site being specifiable by an offset with respect to said update array origin, the pixel specifications of a said update array being concurrently updatable in a parallel memory

transaction,

means for selecting framebuffer pixels for drawing, comprising:

addressing means for accessing a said update array,

write enable means for enabling or preventing writing of a said storage site in said accessed update array,

means for evaluating, concurrently for all pixel sites of said accessed array, the sidedness of the framebuffer pixel whose specification is stored at said pixel site with respect to a directed line specified with respect to said framebuffer, and for deriving a one-bit discriminant signal for each said accessed array pixel site, said write enable means being responsive to a first value of said discriminant signal for

preventing writing to said accessed array pixel site.