Alpha channel not captured

[zhichaoh]

Hello,

RGBA values are ones sent by the underlying layer (the OS). MSS does not alter that data, so if that does not work for you, I am afraid there is nothing that can be done on the MSS level.

Originally posted by @BoboTiG in #151 (comment)

In the windows.py, the following comments seems to strip off the alpha channel data:

python-mss/mss/windows.py

Lines 237 to 242 in 229bd0b

	[2] bmi.bmiHeader.biBitCount = 32
	image_data = create_string_buffer(height * width * 4)
	We grab the image in RGBX mode, so that each word is 32bit
	and we have no striding, then we transform to RGB.
	Inspired by https://github.com/zoofIO/flexx

What is the consideration here?

[BoboTiG]

You could use the bgra attribute. It keeps alpha values.