working together with pillow?

[mokko]

Hi Leo,

thanks for a wonderful module and maintaining it!

Is there a way that I can open an image from pillow directly without writing it to the disk first?

Thanks!

[LeoHsiao1]

As far as I know, you can load the image into memory, then read and write the image from memory:

# Load the image into memory
import io
buf = io.BytesIO()
with open('1.jpg', 'rb') as f:
    buf.write(f.read())

# Open the image in pillow
from PIL import Image
with Image.open(buf) as img:
    img.load()[0, 0]

# Open the image in pyexiv2
import pyexiv2
buf.seek(0)
with pyexiv2.ImageData(buf.read()) as pyexiv2_img:
    pyexiv2_img.read_exif()

# Omit the write operation...

buf.close()

In addition, I found that Pillow lost metadata when it saved the image, for example by executing the following code:

with Image.open('1.jpg') as img:
    img.save('1.jpg', format="JPEG", quality=95)

To avoid losing metadata, you should back up the metadata before Pillow opens the image, and write the metadata after Pillow saves the image.

[LeoHsiao1]

io.BytesIO doesn't support modification, so Pillow should save the image like this:

saved_buf = io.BytesIO()
with Image.open(buf) as img:
    img.save(saved_buf, format="JPEG", quality=95)

[LeoHsiao1]

I was wrong, io.BytesIO supports modification, just truncate it:

buf.truncate(0)
buf.seek(0)

[mokko]

Thank you!

On Sat, Mar 13, 2021 at 9:44 AM LeoHsiao @.***> wrote:

I was wrong, io.BytesIO supports modification, just truncate it:

buf.truncate(0)buf.seek(0)

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