Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
115 words
A method of polygon filling in a by-line, pel driven data processing output in which a polygon to be filled is defined by a multiple line boundary which can be defined by a plurality of selectable pels per scan line, in which a general polygon fill routine is used unless a once round test performed on the vertices of the polygon shows that the sign of the difference between ordinates transverse to the scan line direction of successive vertices of the polygon changes sign exactly two or three times in one circuit of the polygon is satisfied, in which case a faster fill routine is used, possibly with other tests having to be additionally satisfied.
Claim 2
Independent Claim
115 words
A method of polygon filling in a by-line, pel driven data processing output in which a polygon to be filled is defined by a multiple line boundary which can be defined by a plurality of selectable pels per scan line, in which a general polygon fill routine is used unless a once round test performed on the vertices of the polygon shows that the sign of the difference between ordinates transverse to the scan line direction of successive vertices of the polygon changes sign exactly two or three times in one circuit of the polygon is satisfied, in which case a faster fill routine is used, possibly with other tests having to be additionally satisfied.
Claim 3
Dependent Claim
49 words
A method as claimed in claim 1, wherein there are two possible alternative faster fill routines, the slower of which is dependent on the once round test only, the other being dependent on an additional test, the polygon being filled by the fastest fill routine permitted by the tests.
Claim 4
Dependent Claim
49 words
A method as claimed in claim 2, wherein the tests are embedded in the routines and the fastest fill routine is attempted until either test fails, whereat it is exited to the next slower routine, and if the test thereof fails, it is exited to the general fill routine.
Claim 5
Dependent Claim
87 words
A method as claimed in claim 2 or claim 3, wherein the additional test is a conventional turning test determining that the angles subtended by adjacent boundary lines of the polygon have the same sign, the fastest fill routine traversing each boundary line in turn and compiling a single table of maximum and minimum ordinate pairs for selectable pels for each of the scan lines traversing the polygon and, thereafter, using the table to switch the pels defined by such ordinate pairs together with all intervening pels.
Claim 6
Independent Claim
78 words
A method as claimed in any of claims 2 to 4, wherein the slower fast fill routine compiles two tables of maximum and minimum ordinate pairs for the selectable pels of the respective ends of the scan lines traversing the polygon and, thereafter, using the combination of the two tables to determine the absolute maximum and minimum ordinate pairs for each scan line and to switch the pels defined by such ordinate pairs together with all intervening pels.
Claim 7
Dependent Claim
25 words
A method as claimed in either claim 5 or claim 6, wherein the table/tables is/are compiled whilst traversing the boundary lines of the polygon sequentially.
Claim 8
Dependent Claim
240 words
A method as claimed in claim 6, wherein the maximum/minimum selection logic is dependent on the octant of the boundary line being traversed - the octants being referenced I through VIII, anticlockwise, with the scan line direction being parallel to the I/VIII - IV/V octant boundaries - and the lines of the polygon are traversed sequentially while conceptually stepping repetitively from a previous scan line to a next scan line during said sequential traverse: and. if the current line is in octant I, a last selectable pel on the previous scan line is selected after stepping from the previous scan line to the next scan line, and the last selectable pel on the next scan line is selected if the next scan line is a last scan line; if the line is in octant V, the last selectable pel on the previous scan line is selected after stepping from the previous scan line to the next scan line while the last selectable pel on the next scan line is selected if the next scan line is a last scan line; if the line is in octant II or octant III or octant VI or octant VII, the selectable pel on said next scan line is selected; and if the line is in octant IV or octant VIII, the first selectable pel on the next scan line is selected after stepping from the previous scan line to the next scan line.