crop_pictures.py

#!/usr/bin/env python
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# Copyright (c) 2012, Philipp Wagner
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import sys, math 
from PIL import Image

def Distance(p1,p2):
     dx = p2[0] - p1[0]
     dy = p2[1] - p1[1]
     return math.sqrt(dx*dx+dy*dy)

def ScaleRotateTranslate(image, angle, center = None, new_center = None, scale = None, resample=Image.BICUBIC):
     if (scale is None) and (center is None):
       return image.rotate(angle=angle, resample=resample)
     nx,ny = x,y = center
     sx=sy=1.0
     if new_center:
       (nx,ny) = new_center
     if scale:
       (sx,sy) = (scale, scale)
     cosine = math.cos(angle)
     sine = math.sin(angle)
     a = cosine/sx
     b = sine/sx
     c = x-nx*a-ny*b
     d = -sine/sy
     e = cosine/sy
     f = y-nx*d-ny*e
     return image.transform(image.size, Image.AFFINE, (a,b,c,d,e,f), resample=resample)

def CropFace(image, eye_left=(0,0), eye_right=(0,0), offset_pct=(0.2,0.2), dest_sz = (70,70)):
     # calculate offsets in original image
     offset_h = math.floor(float(offset_pct[0])*dest_sz[0])
     offset_v = math.floor(float(offset_pct[1])*dest_sz[1])
     # get the direction
     eye_direction = (eye_right[0] - eye_left[0], eye_right[1] - eye_left[1])
     # calc rotation angle in radians
     rotation = -math.atan2(float(eye_direction[1]),float(eye_direction[0]))
     # distance between them
     dist = Distance(eye_left, eye_right)
     # calculate the reference eye-width
     reference = dest_sz[0] - 2.0*offset_h
     # scale factor
     scale = float(dist)/float(reference)
     # rotate original around the left eye
     image = ScaleRotateTranslate(image, center=eye_left, angle=rotation)
     # crop the rotated image
     crop_xy = (eye_left[0] - scale*offset_h, eye_left[1] - scale*offset_v)
     crop_size = (dest_sz[0]*scale, dest_sz[1]*scale)
     image = image.crop((int(crop_xy[0]), int(crop_xy[1]), int(crop_xy[0]+crop_size[0]), int(crop_xy[1]+crop_size[1])))
     # resize it
     image = image.resize(dest_sz, Image.ANTIALIAS)
     return image

if __name__ == "__main__":
     image =  Image.open("arnie.jpg")