Patent ID: 7274370

Claim:
A system for rendering application windows, comprising: a primary frame buffer for providing window data for output to a display device; a classic application program configured to paint content of at least one window associated with the classic application program directly to a display frame buffer that provides output to a display device; a classic frame buffer, configured to receive the painted content of the windows associated with the classic application program from the classic application program; a compositor application program configured to paint content of at least one window associated with the compositor application program to a back buffer; a plurality of back buffers, each back buffer configured to receive painted content of a window from a compositor application program; a compositor configured to: receive from the classic frame buffer the contents of the classic frame buffer, including geometry of each of the windows associated with the classic application program, and to determine a first visible region for each of the windows with respect to the other windows associated with the classic application program; receive from each back buffer the painted content and geometry of the window stored in the back buffer; determine for each of the windows associated with the classic application program and for each of the windows associated with the compositor application program a second visible region, the second visible region determined with respect to the geometry of each of the windows stored in the back buffer and the classic frame buffer; and to output to the primary frame buffer the second visible region for each of the windows associated with the classic application program and each of the windows associated with the compositor application program.