The procedure tk_chooseColor pops up a dialog box for the user to select a color. The following
option-value pairs are possible as command line arguments:
-initialcolorcolor
Specifies the color to display in the color dialog when it pops up. color must be in a form
acceptable to the Tk_GetColor function.
-parentwindow
Makes window the logical parent of the color dialog. The color dialog is displayed on top of its
parent window.
-titletitleString
Specifies a string to display as the title of the dialog box. If this option is not specified,
then a default title will be displayed.
If the user selects a color, tk_chooseColor will return the name of the color in a form acceptable to
Tk_GetColor. If the user cancels the operation, both commands will return the empty string.