切出三角形并混合

Question

您好，请给我一些有关如何从图像中切出4个三角形并将它们混合在一起的技巧，以便它们看起来像这样：

我想使用python来实现此目的。

Answer 1

从这张图片（dog.jpg）开始：

您可以执行以下操作：

#!/usr/bin/env python3

from PIL import Image, ImageDraw

# Open image, generate a copy and rotate copy 180 degrees
im1 = Image.open('dog.jpg')
im2 = im1.copy().rotate(180)
# DEBUG: im2.save('im2.png')

# Get dimensions of image
w, h = im1.size

# Create an alpha layer same size as our image filled with black
alpha = Image.new('L',(w,h))

# Draw 2 white (i.e. transparent) triangles on the alpha layer
draw  = ImageDraw.Draw(alpha)
draw.polygon([(0, 0), (w, 0), (w/2, h/2)], fill = (255))
draw.polygon([(0, h), (w, h), (w/2, h/2)], fill = (255))
# DEBUG: alpha.save('alpha.png')

# Composite rotated image over initial image while respecting alpha
result = Image.composite(im1, im2, alpha)
result.save('result.png')

中间步骤（在代码中带有#DEBUG:的注释）如下：

im2.png

和alpha.png：