Screen capture without user interaction

I'm building an app that needs to be able to take intermittent screen captures of a target window while running in the background. That is, it needs to be able to screenshot a specific window without user in开发者_高级运维teraction.

Say for example I have Photoshop open, I'd like to capture a screenshot of my open Photoshop document every few minutes and save the capture to a file, essentially building a visual history of how the document has changed over time.

Currently I'm searching for a Unix/Mac solution but Window's suggestions are warmly welcomed.

Screencapture & Scrot both require mouse interaction to target a window & from what I've researched Imagemagick requires xwd to launch to get the id of the target window.

I'm looking for a lightweight solution (that I can bundle with my software) or ideally a solution already built into the OS to accomplish this.

Any suggestions would be very much appreciated. Cheers.

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xwd utility can dump particular X11 window content. It accepts window ID to dump as an argument and can be used in non-interactive mode.

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To capture the whole X-desktop on any unix/linux non-interactively you can call:

xwd -root > file

To display the dump:

xwud -in file