Patent ID: 8269788

Claim:
A processor unit for anti-aliasing of a vector graphics image including at least one primitive having at least one edge, wherein the vector graphics image is rasterized into a group of pixels having a first dimension and a second dimension, the rasterization is performed in a rasterization direction parallel to the first dimension, multiple sub-pixel sampling points are associated with each pixel, and a counter value is associated with each sub-pixel sampling point, the processor unit comprising: a counter value calculator configured to calculate counter values for each pixel by one of incrementing and decrementing the counter values based on the positions in said first and second dimensions of the respective sub-pixel sampling points relative to said at least one edge, wherein the counter value calculation is performed for one edge at a time and pixel-by-pixel in the rasterization direction; a counter value recorder configured to store the calculated counter values in an edge buffer; and a pixel coverage value calculator configured to calculate pixel coverage values based on the stored counter values, wherein the calculated pixel coverage values are utilized to produce an alpha value for a pixel for anti-aliasing the vector graphics image, while rasterizing the vector graphics image into the group of pixels, wherein the counter value calculator is further configured to perform the counter value calculation by: one of incrementing and decrementing a counter value associated with a current sub-pixel sampling point inside a current pixel, when the current sub-pixel sampling point intersects a current edge having one of a first vectorial direction and a second vectorial direction, respectively, wherein the first and second vectorial directions are non-parallel with the rasterization direction; one of incrementing and decrementing the counter value associated with the current sub-pixel sampling point inside the current pixel, when the current sub-pixel sampling point is located, in the rasterization direction, behind the current edge having one of the first vectorial direction and the second vectorial direction, respectively; and one of incrementing and decrementing a counter value associated with another sub-pixel sampling point inside a pixel next to the current pixel in the rasterization direction, when the current sub-pixel sampling point is located, in the rasterization direction, before the current edge having one of the first vectorial direction and the second vectorial direction, respectively, and when the current sub-pixel sampling point and the another sub-pixel sampling point are correspondingly positioned inside their respective pixels.