Determining a coverage mask for a pixel
First Claim
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.
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Accused Products
Abstract
The invention relates to a method, a device, a system and a software program product for determining for a pixel a coverage mask reflecting an orientation and possibly a distance from the pixel center of an original edge vector. The pixel is to be employed for displaying at least a part of a geometric primitive on a display, and the original edge vector represents an oriented edge of the geometric primitive. The method comprises as a first step determining one of four quadrants of a Cartesian coordinate system to which the original edge vector belongs due to its orientation. The original edge vector is then transposed into a predetermined one of the four quadrants. Next, a stored coverage mask is fetched, which is associated at least indirectly to the transposed edge vector. Finally, the fetched coverage mask is transformed to the quadrant to which the original edge vector belongs.
44 Citations
17 Claims
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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:
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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; andwherein 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A device 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 device comprising:
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a computing portion for determining one of four quadrants of a Cartesian coordinate system to which an original edge vector belongs due to its orientation; a quadrant disambiguation portion for transposing an original edge vector into a predetermined one of said four quadrants; a coverage mask look-up portion for fetching a stored coverage mask, which coverage mask is associated at least indirectly to a transposed edge vector provided by said transposing portion; a transformation portion for transforming a coverage mask provided by said coverage mask look-up portion to a quadrant determined by said computing portion; means for 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; andmeans for 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 the coverage mask look-up portion for fetching a stored coverage mask fetches a stored coverage mask which is associated to said selected representative edge vector and thereby indirectly to said transposed edge vector; 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 device further comprises means for selecting said first representative edge vectors of said predetermined quadrant as representative edge vector; wherein the coverage mask look-up portion for fetching a stored coverage mask, fetches a stored coverage mask which is associated to said selected representative edge vector; and wherein said device further comprises means for correcting said fetched coverage mask. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A graphic presentation system 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 graphic presentation system comprising said display device and a processing device, said processing device including:
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a computing portion for determining one of four quadrants of a Cartesian coordinate system to which an original edge vector belongs due to its orientation; a quadrant disambiguation portion for transposing an original edge vector into a predetermined one of said four quadrants; a coverage mask look-up portion for fetching a stored coverage mask, which coverage mask is associated at least indirectly to a transposed edge vector provided by said transposing portion; a transformation portion for transforming a coverage mask provided by said coverage mask look-up portion to a quadrant determined by said computing portion; a combining portion for combining transformed coverage masks provided by said transformation portion for a specific pixel and for modifying the color of said pixel for display by said display device based on combined coverage mask; means for 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; andmeans for 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 the coverage mask look-up portion for fetching a stored coverage mask fetches a stored coverage mask which is associated to said selected representative edge vector and thereby indirectly to said transposed edge vector; 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 device further comprises means for selecting said first representative edge vectors of said predetermined quadrant as representative edge vector; wherein the coverage mask look-up portion for fetching a stored coverage mask, fetches a stored coverage mask which is associated to said selected representative edge vector; and wherein said device further comprises means for correcting said fetched coverage mask.
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17. A software program product with a program code 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, which program code is stored on a machine readable carrier, for
determining one of four quadrants of a Cartesian coordinate system to which an original edge vector belongs due to its orientation; -
transposing an original edge vector into a predetermined one of said four quadrants; fetching a stored coverage mask which is associated at least indirectly to a transposed edge vector; and transforming said fetched coverage mask to said quadrant to which an original edge vector belongs due to its orientation; wherein said program code is for execution by a signal processing component; means for 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; andmeans for 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 the coverage mask look-up portion for fetching a stored coverage mask fetches a stored coverage mask which is associated to said selected representative edge vector and thereby indirectly to said transposed edge vector; 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 device further comprises means for selecting said first representative edge vectors of said predetermined quadrant as representative edge vector; wherein the coverage mask look-up portion for fetching a stored coverage mask, fetches a stored coverage mask which is associated to said selected representative edge vector; and wherein said device further comprises means for correcting said fetched coverage mask.
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Specification