Access to text-mode screen captures... as text

Discussion about using the VirtualBox API, Tutorials, Samples.

Access to text-mode screen captures... as text

Postby bifferos » 18. Jun 2019, 11:02

Using VBoxManage I can get a capture of the screen, but I want to do some OS install automation without the benefit of the guest additions (wait for a screen, press a key, etc...). I wondered if there's a trick to getting the text-mode text from the screen before VirtualBox renders it into the frame buffer so I don't have to do OCR on the captured images.

I'm prepared to recompile VB to get this information out, I wondered if anyone knows how difficult it would be?

Thanks!
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Re: Access to text-mode screen captures... as text

Postby mpack » 18. Jun 2019, 11:47

The only place text is available is inside the app which generates it. VirtualBox has no knowledge of what pixels on a graphics display mean in the collective. And even if you're correct that you are using an actual text mode, and not graphics mode displaying a text font, it certainly isn't a stream: there is no requirement for the display to be updated in linear order.

So, no. I'm afraid not.
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Re: Access to text-mode screen captures... as text

Postby smailloux67 » 13. Oct 2021, 19:01

Hi,

Also want to do OS install automation!

It would have been nice to have that feature. It would solve my issue of selecting the correct boot in a EFI GRUB.

Right now, it is a shot in the dark and if the boot order changes for any reason my program wont work.

May be I could compare picture or go through OCR process... A lengthier process for sure.
Or use real HW with a KVM
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Re: Access to text-mode screen captures... as text

Postby scottgus1 » 13. Oct 2021, 19:04

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