1. A method for generating embroidery data based on image data that represents an image including a plurality of pixels, comprising: generating, based on the image data, a plurality of line segment data including respective angle components, respective length components and respective color components, each of the plurality of line segment data corresponding to one pixel group that includes at least one pixel therein and defines a line segment, the angular component indicating a direction in which the line segment extends, the length component indicating a length of the line segment, and the color component indicating a color of the line segment; and generating the embroidery data based on the plurality of line segment data, the embroidery data giving embroidery stitches along the line segments defined by the plurality of line segment data.