Point containment for quadratic Bèzier strokes
First Claim
Patent Images
1. A method of stroking quadratic Bè
- zier path segments, the method comprising;
receiving a quadratic Bè
zier path segment and a stroke width that defines a stroke region of the quadratic Bezier path segment;
generating a hull geometry that bounds the quadratic Bè
zier path segment;
computing a set of parameters for the quadratic Bè
zier path segment;
for each sample point within the hull geometry, writing a result to a stencil buffer indicating whether the sample point is within the stroke region of the quadratic Bè
zier path segment by evaluating a sample point-specific cubic equation based on the set of parameters; and
filling, via a processing unit, the stroke region by writing a color buffer based on the stencil buffer.
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Abstract
One embodiment of the present invention sets forth a technique for stroking rendered paths. Path rendering may be accelerated when a graphics processing unit or other processor is configured to identify pixels that are within half of the stroke width of any point along a path to be stroked. The path is represented by quadratic Bèzier segments and a cubic equation is evaluated to determine whether or not each point in a conservative hull that bounds the quadratic Bèzier segment is within the stroke width.
42 Citations
20 Claims
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1. A method of stroking quadratic Bè
- zier path segments, the method comprising;
receiving a quadratic Bè
zier path segment and a stroke width that defines a stroke region of the quadratic Bezier path segment;generating a hull geometry that bounds the quadratic Bè
zier path segment;computing a set of parameters for the quadratic Bè
zier path segment;for each sample point within the hull geometry, writing a result to a stencil buffer indicating whether the sample point is within the stroke region of the quadratic Bè
zier path segment by evaluating a sample point-specific cubic equation based on the set of parameters; andfilling, via a processing unit, the stroke region by writing a color buffer based on the stencil buffer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- zier path segments, the method comprising;
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12. A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to stroke quadratic Bè
- zier path segments, by performing the steps of;
receiving a quadratic Bè
zier path segment and a stroke width that defines a stroke region of the quadratic Bè
zier path segment;generating a hull geometry that bounds the quadratic Bè
zier path segment;computing a set of parameters for the quadratic Bè
zier path segment;for each sample point within the hull geometry, writing a result to a stencil buffer indicating whether the sample point is within the stroke region of the quadratic Bè
zier path segment by evaluating a sample point-specific cubic equation based on the set of parameters; andfilling the stroke region by writing a color buffer based on the stencil buffer. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
- zier path segments, by performing the steps of;
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20. A system for stroking quadratic Bè
- zier path segments, the system comprising;
a memory that is configured to store data indicating whether sample points are within a stroke region of a path; and a processor that is coupled to the memory and configured to; receive a quadratic Bè
zier path segment and a stroke width that defines the stroke region;generate a hull geometry that bounds the quadratic Bè
zier path segment;compute a set of parameters for the quadratic Bè
zier path segment;for each sample point within the hull geometry, write a result to a stencil buffer indicating whether the sample point is within the stroke region of the quadratic Bè
zier path segment by evaluate a sample point-specific cubic equation based on the set of parameters; andfilling the stroke region by writing a color buffer based on the stencil buffer.
- zier path segments, the system comprising;
Specification