Re: [Fwd: Folow-up question regarding the linux-fb port of gtk]

[Abhishek Chitlangia <abhishek chitlangia jhu edu>]

Owen Taylor wrote:

> On Tue, 2003-07-08 at 14:22, Abhishek Chitlangia wrote:
>  
>
> > I'm in the process of porting gtk to a developmental OS that has its own 
> > basic windowing system that controls all memory and device accesses. 
> > This means that when I open a new display, the mmap call that maps the 
> > display's fb_mem pointer to the memory-mapped linux-fb (/dev/fb0) is 
> > replaces with a call to a function that returns a memory region that is 
> > to be assumed to be the linux fb. Hence, all operations that change the 
> > fb contents (like changing pixel contents) will now have to be followed 
> > up with a call to the windowing system to tell it to blit the contents 
> > onto the actual fb.
> >
> > My question is this:
> > Is there one file or set of files whose functions write directly to the 
> > linux fb?
> > gdkrender-fb.c is one: are there any others?
> >
> > appreciate any help. thanks.
> >    
>
> You probably should look at the --enable-shadow-fb configure option ...
> I'm not sure how finished it is, but it is meant to work exactly
> as you described, where rendering operations go to an intermediate
> frame buffer, then are blitted to the real fb.
Thanks for the suggestion. I spent some time looking at the shadow_fb 
stuff, but finally run into the same problem: In this OS, I don't have 
direct access to the linux-fb; so I need to make a  call to the window 
system with a special "capability" that allows me rights to request a 
blit onto the actual fb. The window system then does the actual 
blitting. I have changed the gdkrender-fb code to make that call 
whenever the fb contents change (set_pixel functions, fill_span 
functions, etc.), but I want to make sure that this is the only file 
that has functions that talk directly to the linux-fb itself (I know.. 
too many "that"s)

Thanks.
-Abhi