from PIL import Image, ImageFilter

import pcf

def edge_detection(image):
    image = image.filter(ImageFilter.GaussianBlur())
    # GaussianBlur is undocumented class, it might not work in future versions
    # of PIL
    image = Image.fromstring('L', image.size, pcf.edge(image.size, image.tostring()))
    return image

def peaks(image):
    image_l = image.load()
    new_image = Image.new('L', image.size)
    new_image_l = new_image.load()
    
    for x in range(2, image.size[0] - 2):
        for y in range(2, image.size[1] - 2):
            pix = (sum([sum([
                - image_l[a, b] 
                    for b in range(y - 2, y + 3)]) 
                    for a in range(x - 2, x + 3)])
                + (16 * image_l[x, y]))
            if pix > 255:
                pix = 255
            if pix < 0:
                pix = 0 
            new_image_l[x, y] = pix
    return new_image

def high_pass(image, height):
    image_l = image.load()
    new_image = Image.new('L', image.size)
    new_image_l = new_image.load()
    
    for x in xrange(image.size[0]):
        for y in xrange(image.size[1]):
            if image_l[x, y] < height:
                new_image_l[x, y] = 0
            else:
                new_image_l[x, y] = image_l[x, y]

    return new_image

def components(image):
    image_l = image.load()
    new_image = Image.new('L', image.size)
    new_image_l = new_image.load()

    components = [None]
    comp_counter = 1

    for y in xrange(1, image.size[1] - 1):
        for x in xrange(1, image.size[0] - 1):
            if image_l[x, y]:
                s = {0}
                s.add(new_image_l[x - 1, y - 1])
                s.add(new_image_l[x, y - 1])
                s.add(new_image_l[x + 1, y - 1])
                s.add(new_image_l[x - 1, y])
                if len(s) == 1:
                    components.append(set())
                    new_image_l[x, y] = comp_counter
                    components[comp_counter].add((x, y))
                    comp_counter += 1
                elif len(s) == 2:
                    s.remove(0)
                    c = s.pop()
                    new_image_l[x, y] = c
                    components[c].add((x,y))
                else:
                    s.remove(0)
                    c1, c2 = s.pop(), s.pop()
                    components[c2].add((x, y))
                    for (x1, y1) in components[c2]:
                        new_image_l[x1, y1] = c1
                    components[c1] = components[c1] | components[c2]
                    components[c2] = None

    new_image = Image.new('L', image.size)
    new_image_l = new_image.load()

    for component in components:
        if component:
            x_c = 0
            y_c = 0
            c = 0
            for (x, y) in component:
                x_c += x
                y_c += y
                c += 1
            new_image_l[int(round(float(x_c)/c)), int(round(float(y_c)/c))] = 255


    return new_image

def components2(image):
    image_l = image.load()
    new_image = Image.new('L', image.size)
    new_image_l = new_image.load()

    components = [None]
    comp_counter = 1

    for y in xrange(2, image.size[1] - 2):
        for x in xrange(2, image.size[0] - 2):
            if image_l[x, y]:

                s = {0}
                for (a, b) in [(a,b) for a in range(x - 2, x + 3) 
                          for b in range(y - 2, y + 1)]:
                    if not (b == y and a >= x):
                        s.add(new_image_l[a, b])

                if len(s) == 1:
                    components.append(set())
                    new_image_l[x, y] = comp_counter
                    components[comp_counter].add((x, y))
                    comp_counter += 1
                elif len(s) == 2:
                    s.remove(0)
                    c = s.pop()
                    new_image_l[x, y] = c
                    components[c].add((x,y))
                else:
                    s.remove(0)
                    c1 = s.pop()
                    components[c1].add((x, y))
                    new_image_l[x, y] = c1
                    for c2 in s:
                        for (x1, y1) in components[c2]:
                            new_image_l[x1, y1] = c1
                        components[c1] = components[c1] | components[c2]
                        components[c2] = None

    new_image = Image.new('L', image.size)
    new_image_l = new_image.load()

    for component in components:
        if component:
            x_c = 0
            y_c = 0
            c = 0
            for (x, y) in component:
                x_c += x
                y_c += y
                c += 1
            new_image_l[int(round(float(x_c)/c)), int(round(float(y_c)/c))] = 255


    return new_image