Python PIL：如果照片区域不够，则使用黑色区域进行图像裁剪

Question

I want to make thumb and crop it to needed size. It works fine, but if my new thumb area is smaller than crop one, all empty space fills with black color. Code:

import os
from PIL import Image

def resize(file_path):
    file, ext = os.path.splitext(file_path)
    im = Image.open(file_path)
    size = (100, 'auto')
    new_path = file + "_.jpg"
    im.thumbnail(size, Image.ANTIALIAS)
    region = im.crop((0, 0, 100, 100))
    region.save(new_path, "JPEG")

Maybe there is some option like max_height for crop method or anything else?

Thanks!

Answer 1

You will need to apply some simple algorithm there instead of a blind cropping.

• Get the square of maximum size possible in the image with square center aligning with the center of the image. Square of maximum size would be having side equal to max of height or width of the image.

• After getting the square, resample it to the size of your thumbnail dimensions.

• This should work fine for most images, however if you are generating thumbnails for face images, this might not be a good method, and you might need some face recognition techniques for better output.

Answer 2

Are you trying to only conditionally crop the image if its LARGER than 100x100? If so,

def resize(file_path):
    file, ext = os.path.splitext(file_path)
    im = Image.open(file_path)
    size = (100, 'auto')
    new_path = file + "_.jpg"
    im.thumbnail(size, Image.ANTIALIAS)
    if im.size[1] > 100:
        im = im.crop((0, 0, 100, 100))
    im.save(new_path, "JPEG")

Answer 3

I would do it this way:

• If the image is wide, then scale it to be 100px tall. If it's tall, scale it to be 100px wide.

• Crop out the middle 100x100.

   def resize(file_path): file, ext = os.path.splitext(file_path) im = Image.open(file_path) w, h = im.size size = (100, 'auto') if h > w else ('auto', 100) new_path = file + "_.jpg" im.thumbnail(size, Image.ANTIALIAS) w, h = im.size region = im.crop((w/2 - 50, h/2 - 50, w/2 + 50, h/2 + 50)) region.save(new_path, "JPEG") 

Answer 4

I found solution:

import os
from PIL import Image

def resize(file_path):
    file, ext = os.path.splitext(file_path)
    im = Image.open(file_path)
    size = (100, 'auto')
    new_path = file + "_.jpg"
    im.thumbnail(size)
    (width, height) = im.size
    if height >= width: box = (0, 0, 100, 100)
    else: box = (0, 0, 100, height)
    region = im.crop(box)
    region.save(new_path, "JPEG")

Thanks for your responses!