The setPalette method changes the color scheme for Tk.
It does this by modifying the colors of existing widgets and by changing
the option database so that future widgets will use the new color scheme.
If setPalette is invoked with a single argument, the
argument is the name of a color to use as the normal background
color; setPalette will compute a complete color palette
from this background color.
Alternatively, the arguments to setPalette may consist of any number
of name-value pairs, where the first argument of the pair
is the name of an option in the Tk option database and the second
argument is the new value to use for that option. The following
database names are currently supported:
activeBackground foreground selectColor activeForeground highlightBackground selectBackground background highlightColor selectForeground disabledForeground insertBackground troughColorsetPalette tries to compute reasonable defaults for any options that you don't specify. You can specify options other than the above ones and Tk will change those options on widgets as well. This feature may be useful if you are using custom widgets with additional color options.
Once it has computed the new value to use for each of the color options, setPalette scans the widget hierarchy to modify the options of all existing widgets. For each widget, it checks to see if any of the above options is defined for the widget. If so, and if the option's current value is the default, then the value is changed; if the option has a value other than the default, setPalette will not change it. The default for an option is the one provided by the widget (($w->configure('option'))) unless setPalette has been run previously, in which case it is the value specified in the previous invocation of setPalette.
After modifying all the widgets in the application, setPalette adds options to the option database to change the defaults for widgets created in the future. The new options are added at priority widgetDefault, so they will be overridden by options from the .Xdefaults file or options specified on the command-line that creates a widget.
The method bisque is provided for backward compatibility: it restores the application's colors to the light brown (``bisque'') color scheme used in Tk 3.6 and earlier versions.
The use of option database names rather than the configure names is understandable given the mechanism (copied from Tcl/Tk), but is potentially confusing.
The interpolation of different 'shades' of color used for 3D effects in 'RGB' space can lead to undesirable changes in 'hue'. Interpolation in 'HSV' (as used in Tk::ColorEditor) would be more robust and X11R5's color support probably even more so.