Thanx Mark, 1. In windows(OS), there is only one console session running, and hence effectively only one frame buffer. However in Linux we can multiple displays indentified by display numbers. Do each of the Displays have a framebuffer assosciated with them.
2. If there are 5 windows open in a Display:0, who is responsible for writing the display information generated by the windows into the Linux Framebufer(for display0).. 3. Is the region viewed at a window(of an application) level or at the screen level. Appreciate the help. Thanx, Preetham. Is there one frame buffer associated with one display. ----- Original Message ----- From: "Mark Vojkovich" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, July 18, 2002 12:08 PM Subject: Re: [Xpert]Regoin Screen n Framebufer > On Thu, 18 Jul 2002, Preetham wrote: > > > Hi all, > > I was going thru the docs and found a reference to a regoin. What > > exactly constitutes a region in a framebuffer. > > A Region is essentially a list of rectangles. See: > xc/programs/Xserver/include/regionstr.h > > > > Also, is there any information i could get on the Xserver\miext\shadow > > files. Is it to create another shadow frame buffer that other programs > > can read from. > > > I wrote the original shadowfb in xc/programs/Xserver/hw/xfree86/shadowfb. > Basically what it does is wraps all rendering functions and gives the > initializer a callback indicating that the framebuffer was touched and > reports a bounding box around the damaged area. This was written to > get X working on the 3Dfx Voodoo 1 and 2 cards. The idea was that > you could create a proxy framebuffer in system memory for the server > to render into, trap rendering into it with the shadow framebuffer layer > and then copy bounding regions from it into the real framebuffer. > This would allow running X on hardware that had complicated access > to the framebuffer. > > Keith Packard wrote the improved version that you are asking about. > It gives finer detail in its callback. It reports a region rather > than a bounding box. It also has a performance advantage that it > doesn't report after every access to the framebuffer, but rather > coaleses groups of requests and reports them when the X-server > goes back to waiting on its file descriptors. This is roughly > every 20 milliseconds or so. > > The generic use of the shadowfb is just to notify of changes > to windows and the original shadowfb code can do that. I'm not > sure if the new stuff is that generic anymore or if stuff has > creap into it that solidifies it with the intent of proxy > framebuffer operation, but if you have a custom project it probably > wouldn't be too much trouble to modify this for your needs. > > > Mark. > _______________________________________________ > Xpert mailing list > [EMAIL PROTECTED] > http://XFree86.Org/mailman/listinfo/xpert _______________________________________________ Xpert mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/xpert
