The line's offset. For linear features, a positive value offsets the line to the right, relative to the direction of the line, and a negative value to the left. For polygon features, a positive value results in an inset, and a negative value results in an outset.
Name of image in sprite to use for drawing image lines. For seamless patterns, image width must be a factor of two (2, 4, 8, ..., 512). Note that zoom-dependent expressions will be evaluated only at integer zoom levels.