Problem with VNC Connect

[James (Wez) Weatherall]

> Yeah, it's all to do with the fact that the server has to read the video
> memory and decode everything into something that can be understood by the
> client.  The server is equipped to handle 8, 16 and 24-bit colour modes
> (which have integer byte-per-pixel counts) but not less than that.

Not true.  WinVNC can (theoretically under Win95 but in practice under
WinNT) use 1, 4, 8, 16, 24 and 32-bit displays correctly.  1, 4 and 8 are
all treated as 8-bits per pixel palettised as far as the protocol is
concerned.

> Given the number of Wintel boxes that potentially have to work with
> SVGA-only video, someone might like to put in code that converts 16-colour
> video into a standard 256-colour format?

The problem seems to be in the GetDIBits function in Windows - under Windows
9x it is incapable of translating the planar pixel format used by 1 and 4
bit displays into the chunky format used by 8 bit (and higher) displays.
Instead, it does something strange and trashes WinVNC's stack. :)  NT does
it properly, for some reason.

Cheers,

James "Wez" Weatherall
--
          "Xenophobes should go back to Xenophobia"
Laboratory for Communications Engineering, Cambridge - Tel : 766513
AT&T Labs Cambridge, UK                              - Tel : 343000




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