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import sys import Image from numpy import * def save(a, name): a = a[:,:, newaxis]*255 a = concatenate((a, a, a), 2) Image.fromarray(a).save(name) def adjacent(x,y, img): c = -1 for s,t in [(x-1, y-1), (x,y-1), (x+1, y-1), (x+1, y), (x+1, y+1), (x, y+1), (x-1, y+1), (x-1, y)]: if s < 0 or s >= img.shape[0] or t < 0 or t >= img.shape[1]: continue if img[s,t] == True: c+=1 return c def area_of(yx_1, yx_2, yx_3): y1, x1 = yx_1 y2, x2 = yx_2 y3, x3 = yx_3 return 1/2. * abs(-x2*y1 + x3*y1 + x1*y2 - x3*y2 - x1*y3 + x2*y3) def shapes_of(a): # return the seperate contiguous shapes of a. a = a.copy() while True: Y, X = a.nonzero() b = fill(a, (min(Y),min(X)), False) yield logical_xor(b, a) a = logical_xor(s,a) if not a.any(): break if __name__ == "__main__": i = Image.open(sys.argv[1]) a = asarray(i) # get a minimal polygon bounding the shape in a. a = a[:,:,0].astype(bool) Y, X = a.nonzero() minx, maxx = min(X)-1, max(X)+2 miny, maxy = min(Y)-1, max(Y)+2 b = a[miny:maxy, minx:maxx] save(b, "b.png") Y, X = b.nonzero() YX= zip(Y,X) first = min(YX) x,y = first last = (-1,-1) buf = [(x,y)] # Traverse the shape in a clockwise manner, recording all # pixels as we go. not_done = True while not_done: adj = [(y-1, x-1), (y-1, x ), (y-1, x+1), (y , x+1), (y+1, x+1), (y+1, x ), (y+1, x-1), (y , x-1)] adj = [(s,t) for s,t in adj if b[s,t] == True] scores = [adjacent(s,t, b) for s,t in adj] t = sorted([(scr, st) for scr, st in zip(scores,adj)]) adj = [st for scr, st in t if scr < 6] for s,t in adj: if (s,t) not in YX: continue elif (s,t) not in buf: buf.append((s,t)) y,x = s,t break if (y,x) == last: break if (y,x) == first: break last = (y,x) c = zeros(b.shape).astype(bool) for y,x in buf: c[y,x] = True save(c, "c.png") # simplify polygon min_area = 0.25 i = 0 while True: j,k,m = i, i+1, i+2 if area_of(buf[j], buf[k], buf[m]) < min_area: del buf[k] i = 0 continue else: i+=1 if i+2 >= len(buf): break html = file("c.html", 'w') html.write("<html><body>\n<map name='#c'>") html.write("<area shape='poly' href='www.google.com' coords=\"") html.write(", ".join("%i,%i" % (x,y) for y,x in buf)) html.write("\">\n</map><img src='c.png', usemap='#c'></body></html>") html.close() save(c, "c.png")