Patent ID: 7006110
Filing Date: 2006-02-28
Classification: G06T

Abstract:
1. A method for determining for a pixel a coverage mask reflecting an orientation of an original edge vector, which pixel is to be employed for displaying at least a part of a geometric primitive on a display, wherein said original edge vector represents an oriented edge of said geometric primitive, said method comprising: a) determining one of four quadrants of a Cartesian coordinate system to which said original edge vector belongs due to its orientation; b) transposing said original edge vector into a predetermined one of said four quadrants; c) fetching a stored coverage mask which is associated at least indirectly to said transposed edge vector; d) transforming said fetched coverage mask to said quadrant to which said original edge vector belongs; and defining representative edge vectors having different, predetermined orientations, said representative edge vectors being distributed by said predetermined orientations in a rotationally symmetric manner to said four quadrants of said Cartesian coordinate system, such that if the set of representative edge vectors defined for one quadrant is rotated in steps of 90°, the resulting edge vectors correspond exactly to the set of representative edge vectors defined for another quadrant, said method further comprising after step b) selecting one of said representative edge vectors in said predetermined quadrant, which representative edge vector has a similar orientation as said transposed edge vector, wherein step c) comprises fetching a stored coverage mask which is associated to said selected representative edge vector and thereby indirectly to said transposed edge vector; and wherein a first representative edge vector of said predetermined quadrant lies on a first border to a first neighboring quadrant of said predetermined quadrant, wherein a representative edge vector lying on a second border to a second neighboring quadrant of said predetermined quadrant constitutes a first representative edge vector of said second neighboring quadrant, wherein in case said transposed edge vector has a similar orientation as said first representative edge vector of said second neighboring quadrant, said method comprises as an exceptional additional step after step b) selecting said first representative edge vectors of said predetermined quadrant as representative edge vector, wherein step c) comprises fetching a stored coverage mask which is associated to said selected representative edge vector, and as an exceptional additional step after step c) correcting said fetched coverage mask.