1. A computer-implemented method, comprising: identifying a bit-mapped image of a line or polygon shape, the image including a plurality of pixels; mapping the bit-mapped image to a texture map that is larger in at least one dimension than the bit-mapped image; overlaying the bit-mapped image and the texture map; computing pixel shading for pixels between an outer edge of the bit-mapped image and the texture map by measuring a distance from particular ones of the pixels to a line near an edge of the bit-mapped image; and displaying the bit-mapped image with the pixels between an edge of the bit-mapped image and an edge of the texture map at its edge shaded according to the computed pixel shading, wherein the texture map is an integer number of pixels larger than the bit-mapped image in the at least one dimension.