[Bug 46257] New: PrintWindow returns black image

https://bugs.winehq.org/show_bug.cgi?id=46257

Bug ID: 46257
           Summary: PrintWindow returns black image
           Product: Wine
           Version: 3.17
          Hardware: x86
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: user32
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

On Windows I can get an image of a win32 window using PrintWindow, on Wine it
just returns a black image of the size of the window.

I ran this code

https://stackoverflow.com/questions/19695214/python-screenshot-of-inactive-w...

And changed the app from Calculator (which is Universal in Windows now) to
Notepad.

[Bug 46257] PrintWindow returns black image

https://bugs.winehq.org/show_bug.cgi?id=46257

--- Comment #1 from Nikolay Sivov  ---
Could you attach a test program to reproduce this?

[Bug 46257] PrintWindow returns black image

https://bugs.winehq.org/show_bug.cgi?id=46257

--- Comment #2 from Stuart Axon  ---
Here's the code I use to grab the screenshot
https://gist.github.com/stuaxo/70e00c1535d4348196969af6dd4d731d

It's python though, it might take a bit longer to get something together with
C/C++ as I don't really know what I'm doing when it comes to that or windows
development.

[Bug 46257] PrintWindow returns black image

https://bugs.winehq.org/show_bug.cgi?id=46257

--- Comment #3 from Nikolay Sivov  ---
Ok, what do I need to install in Wine prefix to run this?

[Bug 46257] PrintWindow returns black image

https://bugs.winehq.org/show_bug.cgi?id=46257

--- Comment #4 from Stuart Axon  ---
I'm having a go at something in C++, I'll try and come back with the detailed
python install instructions and a single file you can run, it got complicated
by a few bugs.

The short version is, installing python3.5 or 3.6. then using pip to install
pywin32.

(I would recommend python2.7, but there seemed to be a bug in pywin32 that
prevented this).

I had to use wine-staging as there was a bug stopping install of 3.5 or 3.6.

Once it's installed use pip to install pywin32.

...

Except this may not work, I managed to make a patch to pip that made this able
to work in Wine.

I'll do it again and document it here, but if you manage to get any version of
python installed under wine with pywin32, let me know - alternately just wait
for further info :)

[Bug 46257] PrintWindow returns black image

https://bugs.winehq.org/show_bug.cgi?id=46257

--- Comment #5 from Stuart Axon  ---
Hi,
   Here is some CPP code that grabs a screenshot of a window.
It's not the same as the python code, but grabbing screenshots does fail under
Wine.

Thought I had an MFC version (a port of the python code) working before, Xmas
.. but definitely isn't working now, so I've commented that out (and probably
broken more things).

https://gist.github.com/stuaxo/cba5921832201c93a0de1da28aeffcff

Code is a bit of a mishmash of C/C++ idioms as it's code-by-googling

You can run notepad then capture it like

capture-window -l Notepad

[Bug 46257] PrintWindow returns black image

https://bugs.winehq.org/show_bug.cgi?id=46257

--- Comment #6 from Stuart Axon  ---
Replaced the example code with something slightly better

https://github.com/stuaxo/capture_window/