dispwin
Author: Graeme Gill

## spectro/dispwin

### Summary

This utility has several different but related functions. When given as a file argument an ICC profile containing vcgt "gamma" curves, or an Argyll video calibration .cal file, it will load that calibration into the chosen display. It can also install or uninstall a profile in the system for the chosen display, or set the display calibration to that in the currently installed system profile. By default it displays a test window the same as that used by dispcal and dispread, to test this functionality. It can also be used to test the ability to load video card LUT curves to each display, and to test how the console Bell will sound when used with some instruments (ie. Eye-One Pro).

### Usage

dispwin [options] [calfile]
-v Verbose mode
-display displayname [X11 only] Choose X11 display name
-d n[,m] [X11 only] Choose the display from the following list (default 1),
and optionally choose a different display m for Video LUT access.
-d n [Not X11] Choose the display from the following list (default 1)
-P ho,vo,ss Position test window and scale it
ho,vi: 0.0 = left/top, 0.5 = center, 1.0 = right/bottom etc.
ss: 0.5 = half, 1.0 = normal, 2.0 = double etc.
-F Fill whole screen with black background
-i Run forever with random values
-G filename Display RGB colors from CGATS file
-m Manually step through colors
-r Test just video LUT loading & Beeps
-n Test native display values (rather than through Video LUT)
-s filename.cal Save the currently loaded Video LUT to 'filename'
-c Load a linear display calibration (clear calibration)
-V Verify that calfile/profile cal. is currently loaded in LUT
-I Install profile for display and use it's calibration
-U Un-install profile for display
-S d Specify the install/uninstall scope for OS X [nlu] or Vista [lu]
d is one of: n = network, l = local system, u = user (default)
-L Load installed profiles cal. into Video LUT
-D [X11 only] Run in daemon loader mode for given X11 server
-E [level] Print debug diagnostics to stderr
calfile Load display calibration (.cal or .icm) into LUT, and exit.

### Comments

The -v flag makes the program more verbose..
display: When running on a UNIX based system that used the X11 Windowing System, dispwin will by default use the $DISPLAY environment variable to determine which display and screen to read from. This can be overridden by supplying an X11 display name to the -display option. Note that if Xinerama is active, you can't select the screen using $DISPLAY or -display, you have to select it using the -d parameter.
-d: By default the location of the test window will be the main display. If the system has more than one display or screen, an alternate display/screen can be selected with the -d parameter. If you invoke dispwin so as to display the usage information (i.e. "dispcal -?" or "dispcal --"), then the discovered displays/screens will be listed. Multiple displays may not be listed if they appear as a single display to the operating system (ie. the multi-display support is hidden in the video card driver). On UNIX based system that used the X11 Windowing System, the -d parameter will override the screen specified by the $DISPLAY or -display parameter.
Note that if the VideoLUTs for a display are not accessible, dispwin will fail when it attempts to access them. This could be because you are trying to access a remote display, and the remote display doesn't support the XF86VidMode extension, or perhaps you are running multiple monitors using NVidia TwinView, or MergedFB, and trying to access anything other than the primary monitor. TwinView and MergedFB don't properly support the XF86VidMode extension for multiple displays. Xinerama does properly support calibration of multiple displays. See also below, on how to select a different display for VideoLUT access. Also note that dispwin will fail if the Visual depth doesn't match the VideoLUT depth. Typically the VideoLUTs have 256 entries per color component, so the Visual generally needs to be 24 bits, 8 bits per color component.
-d n[,m]Because of the difficulty cause by TwinView and MergedFB in X11 based systems, you can optionally specify a separate display number after the display that is going to be used to present test patches, for accessing the VideoLUT hardware. This must be specified as a single string, e.g. -d 1,2 . Some experimentation may be needed on such systems, to discover what screen has access to the VideoLUT hardware, and which screens the test patches appear on. You may be able to calibrate one screen, and then share the calibration with another screen. Profiling can be done independently to calibration.
The -P parameter allows you to position and size the test patch window. By default it is places in the center of the screen, and sized appropriately for the type of instrument. The ho and vo values govern the horizontal and vertical offset respectively. A value of 0.0 positions the window to the far left or top of the screen, a value of 0.5 positions it in the center of the screen (the default), and 1.0 positions it to the far right or bottom of the screen. The ss parameter is a scale factor for the test window size. A value of 0.5 for instance, would produce a half sized window. A value of 2.0 will produce a double size window. Note that the ho,vo,ss numbers must be specified as a single string (no space between the numbers and the comma).
For example, to create a double sized test window at the top right of the screen, use -P 1,0,2 .
The -F flag causes the while screen behind the test window to be masked with black. This can aid black accuracy when measuring CRT displays or projectors.
By default dispwin will put a test window on the selected display, and display some test colors, before darkening then brightening the screen by loading video LUT values, test the bell sounds, then restore the original values and exit.
If the -i flag is set, then dispwin will display the preset sequence, then random test colors forever.
If the -G parameter is set, then dispwin will display the sequence of RGB color in the supplied CGATS file, e.g. a .ti1 file. Typically this might the used with the -m option to manually measure a set of test patches.
If the -m flag is set, then dispwin will display the preset sequence then exits, but advances manually after each return key.
If the -r flag is set, then dispwin will test just the loading of video LUT values by first darkening, then lightening the screen, before exiting.
If the -n flag is set, then dispwin will display the colors directly on the display, rather than having the color values translated through the currently loaded Video LUTs.
If a -s filename.cal option is used, then rather than displaying a test window, dispwin will save the currently loaded calibration curves to the given calibration file. Note that other functions such as clearing or loading a calibration can be performed after this action.
If a -c flag is used, then rather than displaying a test window, dispwin will load the selected display with a linear set of Video LUT curves, effectively clearing the calibration, and will then exit. Note that other functions such as loading a calibration can be performed after this action.
If a -V flag is used, then rather than loading the calibration specified as the final argument, the currently loaded calibration will be verified as being the same as the given calibration file. If this is combined with the -L flag, the currently loaded calibration will be verified as being the same as the installed system profile for the display.
-I: The ICC profile specified as the final argument will be installed as the default operating system profile for the chosen display, and the display calibration will be set to the calibration tag ('vcgt' tag, if any) in that profile.. On MSWindows and OS X this means that the profile will be copied to the appropriate color profile directory and registered with the operating system. For Linux X11 systems, the profile will be installed using the ucmm convention, and the X11 _ICC_PROFILE property in the root window, and also the the XrandR 1.2 X11 _ICC_PROFILE output property on systems that are running XrandR 1.2 or later. The latter is following this convention for allowing applications to locate the display profile for a particular X11 display, and expands it to accomodate XrandR 1.2. Note that for X11 systems, the properties are not persistent, and will need to be loaded each time the X11 server is started (see the -L flag).
-U: The ICC profile specified as the final argument will be un-installed as the default operating system profile for the chosen display. The display calibration will remain unchanged.
-S d: Some systems have more than one profile scope that an installed profile will apply to, and this parameter allows overriding the default scope. On OS X, there is a choice of three scopes: n: for network scope, if people are sharing profiles over a network, l: local system scope, which installs the profile for all users of a system, and the default u, which covers just the user installing the profile. On Linux or Microsoft Vista, just the local system l and user u scope are available. Note that you may need to run dispwin with elevated privileges to be able to successfully use network or local system scope. This option also applies to uninstalling a profile.
-L: This option fetches the current installed system profile for the chosen display, and sets the display to the calibration tag ('vcgt' tag, if any) in the profile. This is a convenient way of initializing the display on system startup from the installed display profile, if the system doesn't not do this automatically .
-D: Experimental. When running on a UNIX based system that used the X11 Windowing System, this option runs dispwin in a "daemon" mode where it monitors the given X11 server, waiting for any changes in monitors that may require loading a matching ICC profile (ie. such as re-configuring, plugging in a different monitor etc.) This only works if XRandR 1.2 is available on the server. By default dispwin runs silently, and will not terminate. If the -v option is given, it will emit messages to stdout to show what it is doing. When it is first invoked, it will load the installed profiles of all the screens of the given X11 server.
The -E flag causes diagnostics to be printed to stdout. A level can be set between 1 .. 9, that may give progressively more verbose information. This can be useful in tracking down why an operation fails.
The final optional parameter on the command line is the name of an ICC profile that contains a Video LUT vcgt tag, or an Argyll .cal format display calibration. If this parameter is provided, then the selected display will be loaded with the given calibration. If the -V flag was given, then it is verified that this calibration is the currently loaded one. This may be useful in initializing a system to the current calibration on system startup, although a better way may be to install the profile (-I option), and then just use -L. Note that the vcgt tag interpretation within Argyll is consistent with that of the originators of the tag. Other ICC profile vcgt implementations may not be so consistent.
NOTE that on an X11 system, if the environment variable ARGYLL_IGNORE_XRANDR1_2 is set (ie. set it to "yes"), then the presence of the XRandR 1.2 extension will be ignored, and other extensions such as Xinerama and XF86VidMode extension will be used. This may be a way to work around buggy XRandR 1.2 implementations.