Abstract: A chain code process for encoding or compressing contours of masks, objects, sprites, and other graphical features, limits the number of chain codes and defines them relative to the alignment of adjacent pairs of pixels. The chain code direction for a pair of contour pixels is defined relative to the alignment direction of an immediately adjacent pair of pixels. A three-point chain code of this invention includes chain codes that correspond to contour pixel alignments in a forward direction, a leftward direction, and a rightward direction. The forward direction indicates that the alignment direction for a pair of contour pixels is the same as the alignment direction of an immediately adjacent pair of pixels. The rightward and leftward alignment directions indicate that the alignment direction for a pair of contour pixels deviate to the right and left, respectively, from the forward direction.