"Blitter" in X11?
 

RPi-2B w/ 32GB RAM, 1 TB USB drive, 1920x1080 Touch Monitor, running Raspbian:

I need to save and restore rectangles in an X11 window quickly in order to use dialog boxes. Does graphic support for Linux generally (and the RPi specifically) include the "blitter" found on graphics for the Intel PC family -- that is, hardware that supports DMA transfer between graphics and main RAM?

I know that X11 was designed for servers and clients that lie at either ends of networks, so maybe the better question is, Does X11 define a call to move raster data between a screen window and malloc'd RAM?

Thanks for your attention.

can you not just use double buffering and offscreen bitmaps both of which x11 supports?
if xserver is running on older hardware you should check that x11 is supported on that system first.

Keith,

You wrote,
>... just use double buffering and offscreen bitmaps ...

Guessing that "bitmap" was a key word -- always the top problem in discovering something about Linux, especially in graphics: guessing the keywords -- I Googled up

http://www.x.org/releases/X11R7.7/do...x.html#pixmaps

and believe xcb_copy_area() may do the job. Will report after further investigation.

in xlib look at xcopyarea to copy a pixmap from/to a window or other pixmap, use xcopyplane to only copy a 1 bit bitmap, see the manpages for more details