Converting an autopy bitmap to a Pillow image

Question

I'm developing a screen scraper in Python, using Autopy and Pillow.

Is it possible to convert a bitmap object to a Pillow image object?

My current solution is to save the bitmap object as an image file, and then use the path to create a Pillow image object. This approach is really slow because of harddrive I/O.

My current (very slow) solution:

from PIL import Image
import autopy

bitmap_object = autopy.bitmap.capture_screen()
bitmap_object.save('some/path.png') # VERY SLOW!
img = Image.open('some/path.png')

Question: Can the above functionality be achieved without saving the bitmap object to the harddrive?

Answer 1

Looks like now this has a solution from autopy:

import autopy
import PIL.Image

bmp = autopy.bitmap.capture_screen()
width, height = int(round(bmp.width * bmp.scale)), int(round(bmp.height * bmp.scale))
img = PIL.Image.frombytes('RGB', (width, height), bytes(bmp))

Answer 2

After looking through the source code it looks like there is not a way to directly access the raw bitmap. However, you can get an encoded copy.

First, get its encoded representation.

bitmap_encoded = bitmap_object.to_string()

This is encoded as "b", followed by the width, comma, height, comma, and a base64 encoding of zlib compressed raw bytes. Parse the encoded data:

import base64
import zlib

# b3840,1080,eNrsf...H1ooKAs=
#      ^    ^
first_comma = bitmap_encoded.find(',')
second_comma = bitmap_encoded.find(',', first_comma + 1)

# b3840,1080,eNrsf...H1ooKAs=
#  ^  ^
width = int(bitmap_encoded[1:first_comma])

# b3840,1080,eNrsf...H1ooKAs=
#       ^  ^
height = int(bitmap_encoded[first_comma+1:second_comma])

# b3840,1080,eNrsf...H1ooKAs=
#            ^
bitmap_bytes = zlib.decompress(base64.b64decode(bitmap_encoded[second_comma+1:]))

When I tested this on my machine, the red and blue channels were backwards so I'm assuming the bitmap from autopy is RGB encoded instead of the typical BGR encoding that BMP files use which is what PIL expects. Finally, load the image with PIL:

img = PIL.Image.frombytes('RGB', (width, height), bitmap_bytes, 'raw', 'BGR', 0, 1)

To load the image normally without swapping the red and blue channels, do:

img = PIL.Image.frombytes('RGB', (width, height), bitmap_bytes)