png2palette.py
1c48bdde7c9cmaster

png2palette.py
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			#!/usr/bin/env python


			import sys
			import Mtools as mt
			import Ptools as pt
			from numpy import *

			n = -100

			file = sys.argv[1]

			img = mt.img_open(file)


			r,g,b = img.split()

			sizex,sizey= img.size

			# get
			ra = array(r.getdata())
			ga = array(g.getdata())
			ba = array(b.getdata())


			#ra.shape=img.size
			#ra = ra.transpose()
			#ra = ra.mean(axis=1)
			#ra = ra[:n]

			#ga.shape=img.size
			#ga = ga.transpose()
			#ga = ga.mean(axis=1)
			#ga = ga[:n]

			#ba.shape=img.size
			#ba = ba.transpose()
			#ba = ba.mean(axis=1)
			#ba = ba[:n]

			# plot


			dx = float(255.5)/len(ra)
			x = arange(0,255+dx,dx)


			pt.plot(x,ra,c='r')
			pt.plot(x,ga,c='g')
			pt.plot(x,ba,c='b')


			# interpolate

			from scipy import interpolate
			sfact = 1.
			k = 2
			n=len(x)
			s1 = n-sqrt(2*n)
			s2 = n+sqrt(2*n)
			s = s1*sfact

			tckr = interpolate.fitpack.splrep(x,ra,s=s,k=k)
			tckg = interpolate.fitpack.splrep(x,ga,s=s,k=k)
			tckb = interpolate.fitpack.splrep(x,ba,s=s,k=k)

			i = arange(0,256)
			r = interpolate.fitpack.splev(i,tckr)
			g = interpolate.fitpack.splev(i,tckg)
			b = interpolate.fitpack.splev(i,tckb)



			pt.plot(i,r,c='r')
			pt.plot(i,g,c='g')
			pt.plot(i,b,c='b')
			pt.show()


			# write palette
			name = 'gnedin1'
			f = open(name,'w')
			f.write("# table rgb (%s)\n"%name)

			for i in range(256):
			f.write("%3d %3d %3d\n"%(r[255-i],g[255-i],b[255-i]))

			f.close()