ikatake

require 'rmagick'
iclude Math

def annotate_on_arc(img, str, wc, r, x0, y0, theta0, font, fill, stroke, size)
# img 		rmagick draw Macick::Image object
# str		annotate string
# wc		width of one charator[px]
# r, x0 ,y0	radius and center point[px] of circle(arc)
# theta0	angle at center of string[rad]
# font, size	font familiy and font size[pt?]