~4Dgifts/toolbox/src/exampleCode/X/xshowcmap2 README
This extension to xshowcmap and this winfo script, can be very helpful
in debugging problems that occur when dealing with multiple colormaps
and/or visuals.
xshowcmap2 has been modified with three new optional arguments:
-visid allows specifying the visual id.
-cmap allows specifying the colormap id.
-windowid allows specifying a window id. The visual and
colormap IDs are obtained from the window.
-visid and -cmap are often used together. Neither of these should
be used with -windowid, which is an alternate way of providing the
same information.
Note xshowcmap2 is not particularly robust when given invalid values
for these arguments, and usually will exit with a cryptic X error.
The window ID's, visual ID's, and colormap ID's, can be obtained
using xwininfo and xprop. Alternatively, the enclosed script,
winfo, can be used to obtain the same information. Winfo, first
does an xprop on a selected window (which can be obtained either by
clicking on the window or with the -id argment). It looks for the
WM_COLORMAP_WINDOWS property on that window. If it finds that
property, it does an xwininfo on each window listed. If it does not
find it, it does an xwininfo on the top level window. In either
case, the output from xwininfo is filtered to only show the
information pertinant to colormaps and visuals. The returned values
can then be passed on to xshowcmap2.
As an example using this, consider the toolchest, which in addition
to the default colormap, also uses a visual in the popup planes for
its menus. Run the command winfo, and click on the toolchest. You
will see output something like this:
window 0x2c00039
colormap windows 0x2c00038 0x2c00039
xwininfo: Window id: 0x2c00038 (has no name)
Depth: 2
Visual id: 0x20
Visual Class: PseudoColor
Colormap: 0x2c00006 (installed)
xwininfo: Window id: 0x2c00039 "ToolChest"
Depth: 8
Visual id: 0x25
Visual Class: PseudoColor
Colormap: 0x32 (installed)
The first line gives you the window ID. The second line shows that
this window has a WM_COLORMAP_WINDOWS property, which includes two
windows. This is followed by information on each of the windows in
that property. The first, of depth 2, is the popup visual, and the
second, of depth 8, is the default visual. To look at the popup
colormap, you can issue the command:
xshowcmap2 -windowid 0x2c00038
or, alternatively,
xshowcmap2 -visid 0x20 -cmap 0x2c00006
When looking at colormaps, be aware the usual hardware limitations
on the number of colormaps apply. For example, if you were also
looking at the colormap of another application that also used the
popup planes, only one popup colormap could be in place at a given
time; when one is installed, it kicks the other out.
Documentation
OR, ...