Does x11vnc support the X DAMAGE Xserver extension to find modified regions of the screen quickly and efficiently?
Yes, as of Mar/2005 x11vnc will use the X DAMAGE extension by default if it is available on the display. This requires libXdamage to be available in the build environment as well (recent Linux distros and Solaris 10 have it.) The DAMAGE extension enables the X server to report changed regions of the screen back to x11vnc. So x11vnc doesn’t have to guess where the changes are (by polling every pixel of the entire screen every 2-4 seconds.) The use of X DAMAGE dramatically reduces the load when the screen is not changing very much (i.e. most of the time.) It also noticeably improves updates, especially for very small changed areas (e.g. clock ticking, cursor flashing, typing, etc.) Note that the DAMAGE extension does not speed up the actual reading of pixels from the video card framebuffer memory, by, say, mirroring them in main memory. So reading the fb is still painfully slow (e.g. 5MB/sec), and so even using X DAMAGE when large changes occur on the screen the bulk of the time is still
Yes, as of Mar/2005 x11vnc will use the X DAMAGE extension by default if it is available on the display. This requires libXdamage to be available in the build environment as well (recent Linux distros and Solaris 10 have it.) The DAMAGE extension enables the X server to report changed regions of the screen back to x11vnc. So x11vnc doesn’t have to guess where the changes are (by polling every pixel of the entire screen every 2-4 seconds.) The use of X DAMAGE dramatically reduces the load when the screen is not changing very much (i.e. most of the time.) It also noticeably improves updates, especially for very small changed areas (e.g. clock ticking, cursor flashing, typing, etc.) Note that the DAMAGE extension does not speed up the actual reading of pixels from the video card framebuffer memory, by, say, mirroring them in main memory. So reading the fb is still painfully slow (e.g. 5MB/sec), and so even using X DAMAGE when large changes occur on the screen the bulk of the time is still
