Mechanisms for more efficiently and accurately performing anti-aliasing techniques. A bounding box for a line can be generated that includes both a central region of the line and one or more boundary regions that have various levels of opacity. Vertices for the bounding box can be provided to any of a variety of appropriate entities to interpolate pixel locations within the bounding box and to determine various levels of opacity for pixels, such as vertex shaders and/or pixel shaders. Various techniques can be used to determine a pixel's membership value within one or more of the boundary regions of a bounding box, such as using a distance from an edge of a central region to a center of the pixel and/or an area of the pixel that is located inside the boundary region.