Hans Werner Strube wrote: > If X11 graphics programs request backing store, for instance, with > drawattr.backing_store = Always; > XChangeWindowAttributes(display, drawable, CWBackingStore, &drawattr); > this seems to have no effect. The same program works correctly in Solaris > (SPARC) and IRIX (MIPS). > The memory of my graphics card (8 MB, Rage Mobility) appears sufficient, > since the whole screen would only use 2.3 MB with 24 bits/pixel. It would > be desirable to have this possibility to avoid explicit redrawing after > a portion of the window has been covered or the window has been iconized > and reopened. >
Hans, The amount of memory on your video card is not relevant. All Cygwin/XFree86 graphics operations are computed in system memory and only the resulting pixels are transferred to the screen. Cygwin/XFree86 has support for backing store, but it is not enabled by default. You have to pass the ``+bs'' parameter to XWin.exe to enable backing store support: XWin +bs We have not confirmed whether the backing store actually performs to specification. I just ran XWin with the backing store enabled and xterm running under the mwm window manager failed to redraw its client area correctly when I moved one xterm over another xterm. I cannot tell you if this is a bug with general XFree86 code, with Cygwin-specific XFree86 code, with mwm, or with xterm. I have seen various posting that seem to indicate that backing store support is not trusted anymore... perhaps it is no longer being maintained. It is also possible that I have simply misread or misremembered things. Maybe backing store support is still fully maintained and perhaps we are simply not using it correctly. Harold
