Windows application screenshot

[smallfish06]

windows 10 supports built-in virtual desktop. But when I change desktop from A to B while Pillow process takes screenshot in A, then I get B's screenshot.

The thing i want to know is, was this intended? Cause i don't know well about pillow's goal.
If this is not intended, i'm planning to improve window screen grabber

https://github.com/nulano/Pillow/blob/3c311f5619b1b82e2b91cd2a42e3a44b9526755c/src/display.c#L323

[radarhere]

I don't understand the situation you're describing. Could you rephrase?

Depending on what you're talking about, you may find the 'all_screens' argument helpful - https://pillow.readthedocs.io/en/stable/reference/ImageGrab.html#PIL.ImageGrab.PIL.ImageGrab.grab

Also, be aware that you've linked to code from a fork of Pillow, not the main Pillow repository itself.

[smallfish06]

Sorry for linked to code from a fork of Pillow

https://community.windows.com/en-us/stories/virtual-desktop-windows-10

Windows 10 supports virtual desktop itself. Not the Hyper-V function that we used before.

If i run a script that take a screen shot after 5 seconds, using imagegrab at desktop3
And i change immediately to desktop2

In this case the screenshot is taken in desktop2 even it's running in desktop3

unfortunately even if i use include_layered_windows, all_screens it only takes screenshots of desktop3

[nulano]

Unfortunately, I don't think it is possible to do what you are trying to do. Windows seems to only draw the current desktop, see this Stack Overflow question.

[smallfish06]

Then I think this problem can be solved with 'screenshot of a specific application'

https://stackoverflow.com/questions/19695214/python-screenshot-of-inactive-window-printwindow-win32gui

i successed capturing specific image in other desktop by using this win32gui method. But only if it is visible.

capture from desktop1

How do you think of implementing 'screenshot of a specific application'?

[nulano]

PrintWindow uses a different mechanism not involving the Desktop Window Manager (which is AFAIK the layer implementing virtual desktops on Windows), so it makes sense that it works for this.

I can see two options for where this could be implemented: ImageGrab (which currently deals with desktop screenshots and the clipboard for Windows and macOS) and ImageWin (according to the docs, it seems to be used to draw images directly to HDCs -- Windows Device Contexts). Either way, I expect that the new function would take HWND as a parameter. This would probably be best implemented in C, not with win32gui.

[smallfish06]

Is it possible for me to add such C extension on specific part?
I mean are there any extension guide or C code repository? I have no idea where to add those codes

[nulano]

Display related Windows C code is in the display.c file.

[smallfish06]

thanks:) I'll submit pull request when done with display.c and ImageWin

[radarhere]

I've created #8516 to resolve this by adding a handle argument to ImageGrab.grab() that accepts a HWND.