Extensions

Most interesting X functionality lives in protocol extensions. node-x11 loads them at runtime with X.require(name, callback). The callback receives an extension object carrying the extension's requests, enums and version info; any extension events are registered on the client automatically:

X.require('randr', (err, Randr) => {
  if (err) throw err; // extension missing on this server
  Randr.GetScreenResources(display.screen[0].root, (err, res) => {
    console.log(res.outputs);
  });
});

name is the module name below (the file in lib/ext/), not the on-the-wire extension name. Requiring an extension twice returns the cached instance.

Available extensions

module	X name	what it does
apple-wm	Apple-WM	XQuartz window-manager integration
big-requests	BIG-REQUESTS	requests larger than 256 KiB (enabled automatically at connect)
composite	Composite	redirect window rendering off-screen
damage	DAMAGE	be notified when drawables change
dbe	DOUBLE-BUFFER	flicker-free double buffering
dpms	DPMS	monitor power management
fixes	XFIXES	regions, cursor names, selection tracking
ge	Generic Event Extension	framing for extensions with large events
glx	GLX	OpenGL rendering over the X protocol
present	Present	vsynced pixmap presentation
randr	RANDR	outputs, CRTCs, modes, rotation
record	RECORD	record/replay of the protocol stream
render	RENDER	anti-aliased compositing, gradients, glyphs
res	X-Resource	per-client server resource usage
screen-saver	MIT-SCREEN-SAVER	screen-saver control and notification
shape	SHAPE	non-rectangular windows
shm	MIT-SHM	shared-memory images
sync	SYNC	counters, alarms, fences
xc-misc	XC-MISC	XID range recycling
xinerama	XINERAMA	multi-head screen layout
xinput	XInputExtension	input devices beyond core pointer/keyboard
xkb	XKEYBOARD	keyboard maps, controls, indicators
xtest	XTEST	synthesize input events for testing
xv	XVideo	video output adaptors

Each extension has its own reference page with every request, event and enum — see the Extensions section of the API reference.