##language:zh
'''
含有章节索引的中文 文章模板
'''

::-- hoxide [<<DateTime(2005-07-29T19:19:46Z)>>]
<<TableOfContents>>
== PIL ==
''简述''
Python的图像处理工具集, 功能比较很强大, 配合Numarray使用, 可以做图像处理.

官方页面: [[http://www.pythonware.com/products/pil/]]

=== 例子 ===
==== 用PIL+Numarray处理图像 ====
 建模竞赛题, 读入图像搜索边界, 重构三维模型. 使用了 [[PythonImagingLibrary|PIL]] [[NumArray]] [[GNUPlot]]

{{{
#!python
import Image
from numarray import array
from Gnuplot import Gnuplot
from math import ceil

imsize = (512, 512)
drt = (( 0,  1), (  1,  1), (  1,  0), (  1, -1),
       ( 0, -1), ( -1, -1), ( -1,  0), ( -1,  1))
drt = array(drt)

def dofile(file, z):
    im = Image.open(file)
    a = im.getdata()
    a = array(a).resize(*imsize)
    r = list()
    for i in xrange(imsize[0]):
        for j in xrange(imsize[1]):
            for dx, dy in drt:
                if ( i+dx>=0 and i+dx < imsize[0] and
                     j+dy>=0 and j+dy < imsize[1] and
                     a[i][j] != a[i+dx][j+dy]):
                    r.append((i, j, z))
    return r

def ddfile(file, z):
    im = Image.open(file)
    a = im.getdata()
    a = array(a).resize(*imsize)
    r = getedge(a, z)
    return r

def getedge(a, z):
    imsize = a.shape
    r = list()
    try:
        for i in xrange(imsize[0]):
            for j in xrange(imsize[1]):
                if (a[i,j] == 0):
                    #print i,j
                    raise StopIteration
    except StopIteration:
        r.append((i,j, z))
    if len(r)==0 :
        return None
    nd = 0
    x, y = i, j
    r.append((z, x, y))
    while True:
        for d in xrange(8):
            dd = (nd+d) %8
            if a[x+drt[dd][0], y + drt[dd][1]] == 0:
                r.append((x, y, z))
                x, y = (x, y) + drt[dd]
                nd = (dd + 4 +1) %8
                break
        if x == i and y == j:
            break
    return r
    

def out(ofp):
    np = 30
    for i in xrange(100):
        fname = 'abmp/'+str(i)+'.bmp'
        r = ddfile(fname, i)
        l = len(r)
        step = (l-1.0)/np
        for i in xrange(np):
            x, y, z = r[int(step*i)]
            ofp.write("%d\t%d\t%d\n"%(z, y, x))
        x, y, z = r[0]
        ofp.write("%d\t%d\t%d\n"%(z, y, x))
        ofp.write("\n")
            
def pointplot():
    g = Gnuplot()
    g('set pm3d')
    g('set hidden3d')
    g('splot [0:500] [0:500] [0:500] "oo.dat" w l')
    raw_input("Press Enter to continue...")
    
    
if __name__ == '__main__':
    ofp = open('oo.dat', 'w')
    out(ofp)
    ofp.close()
    pointplot()

}}}