如何从Python中的像素值列表创建PNG图像文件？ [英] How can I create a PNG image file from a list of pixel values in Python?

问题描述

我可以使用如下过程从现有图像文件生成像素值列表：

I can generate a list of pixel values from an existing image file using a procedure like the following:

from PIL import Image
image = Image.open("test.png")
pixels = list(image.getdata())
width, height = image.size
pixels = [pixels[i * width:(i + 1) * width] for i in xrange(height)]

如何将此像素值列表转换回图像文件？

How could I convert this list of pixel values back to an image file?

推荐答案

快速修复

首先，你需要将你的像素元组放在一个非嵌套列表中：

Quick fix

First, you need to have your pixel tuples in a single un-nested list:

pixels_out = []
for row in pixels:
    for tup in row:
        pixels_out.append(tup)

接下来，使用输入图像的属性制作一个新的图像对象，并将数据放入其中：

Next, make a new image object, using properties of the input image, and put the data into it:

image_out = Image.new(image.mode,image.size)
image_out.putdata(pixels_out)

最后，保存它：

image_out.save('test_out.png')

基本问题

列表推导生成列表列表，后者由切片生成（我*宽度：第（i + 1）*宽度）。您的理解可以更容易： pixels = [像素的像素数] 。显然，这会输出相同的列表 pixels ，但您可以使用这个想法对像素执行操作，例如 pixels = [像素的操作（像素）] 。

Fundamental issue

Your list comprehension generates a list of lists, the latter being generated by the slicing (i*width:(i+1)*width). Your comprehension can be much easier: pixels = [pixel for pixel in pixels]. Obviously this outputs the same list, pixels, but you can use the idea to perform an operation on the pixels, e.g. pixels = [operation(pixel) for pixel in pixels].

真的，你打败了它。您无需管理图像尺寸。获取列表中的像素，然后使用 putdata 将它们放入相同大小的图像中，因为它们按照PIL以相同的方式线性化。

Really, you overthought it. You don't have to manage the image dimensions. Getting the pixels in a list, and then putting them into an equal-sized image with putdata keeps the in order because they are linearized the same way by PIL.

简而言之，这就是你的原始代码片段：

In short, this is what your original snippet should have been:

from PIL import Image
image = Image.open("test.png")
image_out = Image.new(image.mode,image.size)

pixels = list(image.getdata())
image_out.putdata(pixels)
image_out.save('test_out.png')

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