Fast, coverage-optimized, resolution-independent and anti-aliased graphics processing

1. A computer-implemented method for stroking a curve comprising:

receiving, at a graphics processing unit, a plurality of vertices representing a control polygon of the curve, wherein the graphics processing unit maintains resolution independence from a central processing unit by:

expanding the control polygon of the curve in at least one location proximate at least one endpoint of the curve;

tessellating the control polygon into a plurality of tiles;

selecting a subset of tiles from the plurality of tiles based on each of the tiles of the subset satisfying a selection criterion;

rasterizing the curve into fragments using only the selected subset of tiles that satisfy the selection criterion, wherein the selection criteria requires a tile in the plurality of tiles to have a vertex within a threshold distance from the curve; and

rendering the curve based on the fragments.

2. The computer-implemented method of claim 1 , comprising discarding unselected tiles of the plurality of tiles.

3. The computer-implemented method of claim 1 , comprising interpolating texture coordinates of vertices of the plurality of tiles.

4. The computer-implemented method of claim 1 , wherein rendering the curve comprises anti-aliasing the curve.

5. The computer-implemented method of claim 1 , wherein the selection criterion requires that a tile in the plurality of tiles include a first vertex inside the curve and a second vertex outside the curve.

6. The computer-implemented method of claim 1 , wherein the threshold distance is at least a portion of a height of one of the plurality of tiles.

7. The computer-implemented method of claim 1 , wherein the curve is a quadratic Bezier curve or a cubic Bezier curve.

8. The computer-implemented method of claim 1 , wherein a width of the curve is less than a device pixel.

9. The computer-implemented method of claim 1 , comprising expanding the control polygon of the curve by a device pixel.

10. A system comprising:

a central processing unit;

a graphics processing unit; and

a memory coupled to the central processing unit and the graphics processing unit and storing instructions, which when executed, cause the graphics processing unit to perform operations comprising:

receiving a plurality of vertices representing a control polygon of a curve;

expanding, by maintaining resolution independence from the central processing unit, the control polygon of the curve in at least one location proximate at least one endpoint of the curve;

tessellating, by maintaining resolution independence from the central processing unit, the control polygon into a plurality of tiles;

selecting a subset of tiles from the plurality of tiles based on each of the tiles of the subset satisfying a selection criterion;

rasterizing the curve into fragments using only the selected subset of tiles that satisfy the selection criterion, wherein the selection criteria requires a tile in the plurality of tiles to have a vertex within a threshold distance from the curve; and

rendering the curve based on the fragments.

11. The system of claim 10 , wherein the instructions further cause the graphics processing unit to perform operations comprising discarding unselected tiles of the plurality of tiles.

12. The system of claim 10 , wherein the instructions further cause the graphics processing unit to perform operations comprising interpolating texture coordinates of vertices of the plurality of tiles.

13. The system of claim 10 , wherein the selection criterion requires that a tile in the plurality of tiles include a first vertex inside the curve and a second vertex outside the curve.

14. The system of claim 10 , wherein the threshold distance is at least a portion of a height of one of the plurality of tiles.

15. A non-transitory computer-readable medium storing a computer readable program, wherein the computer readable program when executed causes a graphics processing unit to perform operations comprising:

receiving a plurality of vertices representing a control polygon of a curve;

expanding, by maintaining resolution independence from a central processing unit, the control polygon of the curve in at least one location proximate at least one endpoint of the curve;

tessellating, by maintaining resolution independence from the central processing unit, the control polygon into a plurality of tiles;

selecting a subset of tiles from the plurality of tiles based on each of the tiles of the subset satisfying a selection criterion;

rasterizing the curve into fragments using only the selected subset of tiles that satisfy the selection criterion, wherein the selection criteria requires a tile in the plurality of tiles to have a vertex within a threshold distance from the curve; and

rendering the curve based on the fragments.

16. The non-transitory computer-readable medium of claim 15 , wherein the computer readable program further causes the graphics processing unit to perform operations comprising discarding unselected tiles of the plurality of tiles.

17. The non-transitory computer-readable medium of claim 15 , wherein the computer readable program further causes the graphics processing unit to perform operations comprising interpolating texture coordinates of vertices of the plurality of tiles.

18. The non-transitory computer-readable medium of claim 15 , wherein the selection criterion requires that a tile in the plurality of tiles include a first vertex inside the curve and a second vertex outside the curve.

19. The non-transitory computer-readable medium of claim 15 , wherein the threshold distance is at least a portion of a height of one of the plurality of tiles.