[syslinux] Using the cat.c32 sample as a functional equivalent to the FN keys in vesa mode

[H. Peter Anvin]

David W. Koeller wrote:
> I have been hacking around with the new vesa boot menus and I had a 
> couple questions.
> 
> Do you currently have a method to set the SHADOWING options that are 
> coded in menumain.c from within the menu config file?  I saw something 
> in readconfig that looked like you were parsing single characters to map 
> to SHADOW_NONE, etc. constants for these parameters, but I did not 
> follow it.  The default shadowing looked horrible on a white background 
> image I was using.  I managed to turn it off by recompiling the 
> menumain.c with different color schemes.
> 

Yes, but you have to get 3.31 to do that.  See MENU COLOR in README.menu 
in 3.31.

> I have modified the cat.c32 sample under com32 to invoke a vesa console 
> video mode and set the color table accordingly based on code from 
> menumain.c.  This can then be called from within vesamenu.c32 to cat a 
> file containing the help text for optional kernel parameters that could 
> be passed at the command prompt.  I would really like to add the 
> equivalent of a boot: prompt at the bottom of this code in the context 
> of vesa so it behaves similar to the traditional FN keys with .msg 
> files.  I currently just issue a get_key call at the end of the cat.c 
> file and inform the user to hit a key to get the boot: prompt which 
> works.  The only drawback is that the help is now gone when they go to 
> type since we are back in a different video mode.
> 
> On the same note, is there a return code or call sequence I can invoke 
> from within cat.c to reload the default calling vesamenu.c32 if the user 
> choses the cat.c32 help and then wants to return to the main menu 
> without first hitting enter through the boot: parameter?

Yes, there is an API call INT 22h AX=0004h Run default command.

> All in all, the new vesa menus are pretty awesome looking.  Great work.

Thank you :)

	-hpa