如何在不写/读的情况下在 Python 中执行 JPEG 压缩
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How to perform JPEG compression in Python without writing/reading
提问by user1245262
I'd like to work directly with compressed JPEG images. I know that with PIL/Pillow I can compress an image when I save it, and then read back the compressed image - e.g.
我想直接使用压缩的 JPEG 图像。我知道使用 PIL/Pillow 我可以在保存图像时压缩图像，然后读回压缩图像 - 例如
from PIL import Image
im1 = Image.open(IMAGE_FILE)
IMAGE_10 = os.path.join('./images/dog10.jpeg')
im1.save(IMAGE_10,"JPEG", quality=10)
im10 = Image.open(IMAGE_10)
but, I'd like a way to do this without the extraneous write and read. Is there some Python package with a function that will take an image and quality number as inputs and return a jpeg version of that image with the given quality?
但是，我想要一种无需额外读写的方法。是否有一些带有函数的 Python 包可以将图像和质量数字作为输入并返回具有给定质量的该图像的 jpeg 版本？
采纳答案by sgammon
For in-memory file-like stuff, you can use StringIO.
Take a look:
对于类似内存文件的内容，您可以使用StringIO. 看一看：
from io import StringIO # "import StringIO" directly in python2
from PIL import Image
im1 = Image.open(IMAGE_FILE)
# here, we create an empty string buffer
buffer = StringIO.StringIO()
im1.save(buffer, "JPEG", quality=10)
# ... do something else ...
# write the buffer to a file to make sure it worked
with open("./photo-quality10.jpg", "w") as handle:
handle.write(buffer.contents())
If you check the photo-quality10.jpgfile, it should be the same image, but with 10% quality as the JPEG compression setting.
如果您检查该photo-quality10.jpg文件，它应该是相同的图像，但质量为 JPEG 压缩设置的 10%。
回答by Super Engine
Using BytesIO
使用 BytesIO
try:
from cStringIO import StringIO as BytesIO
except ImportError:
from io import BytesIO
def generate(self, image, format='jpeg'):
im = self.generate_image(image)
out = BytesIO()
im.save(out, format=format,quality=75)
out.seek(0)
return out
StringIO is missing in Python3.0, ref to : StringIO in python3
Python3.0 中缺少 StringIO，请参考：python3 中的 StringIO
