How to run XQuartz in 16-bit color mode Is it possible to run XQuartz in 16-bit color mode on macOS High Sierra?  I tried the suggestions in this question but they didn't seem to work for 16-bit color.

First, I tried setting the color depth in XQuartz preferences:



When I restarted X and checked the color depth using xwininfo -root it showed Depth: 24.

Next, I tried specifying the color depth inline when starting XQuartz:

xquartz -depth 16


This caused XQuartz to crash with the error: Xquartz: start_x11_server: (ipc/mig) server died

Last, I tried setting the color depth with defaults

defaults write org.macosforge.xquartz.X11 "depth" -int 16


This also resulted in a color depth of 24.

However, setting the color mode to 8-bit using any of the above techniques worked just fine.  XQuartz started up, and xwininfo -root showed Depth: 8.

Any ideas what I might be doing wrong?  I'm running macOS High Sierra and XQuartz 2.7.11 (xorg-server 1.18.4).

Edit: I tried with a value of 15, but xwininfo is still reporting a color depth of 24.
Valid values for "depth" in defaults write org.macosforge.xquartz.X11 "depth" -int n where n is one of the following:


From Display: -1
256 Colors: 8
Thousands: 15
Millions: 24


These values were obtained using defaults read org.macosforge.xquartz.X11 depth after selecting each of the options in the menu.





Here is the output of the defaults (read/write) and xwininfo -root commands:

$ defaults read org.macosforge.xquartz.X11 depth
24
$ defaults write org.macosforge.xquartz.X11 "depth" -int 15
$ defaults read org.macosforge.xquartz.X11 depth
15
$ xwininfo -root

xwininfo: Window id: 0xf1 (the root window) (has no name)

  Absolute upper-left X:  0
  Absolute upper-left Y:  0
  Relative upper-left X:  0
  Relative upper-left Y:  0
  Width: 2560
  Height: 1418
  Depth: 15
  Visual: 0x22
  Visual Class: TrueColor
  Border width: 0
  Class: InputOutput
  Colormap: 0x21 (installed)
  Bit Gravity State: ForgetGravity
  Window Gravity State: NorthWestGravity
  Backing Store State: NotUseful
  Save Under State: no
  Map State: IsViewable
  Override Redirect State: no
  Corners:  +0+0  -0+0  -0-0  +0-0
  -geometry 2560x1418+0+0

$