The .run xvis command compiles and loads the routines found in xvis.pro. By default, XVIS uses only those colors that are available in the current display. Setting the keyword parameter ALL_COLORS will cause XVIS to install its own 256-entry color table, overriding the default. Although this ensures that what you see is what you get, the downside to this method is the color- flashing problem when moving between the IDL viewing window and other windows on the desktop. This is an inherent feature of the X windows system and cannot be "fixed".
XVIS also uses a Courier font if one is available. This default behavior can be over-ridden by setting the keyword parameter FONT to a valid font name. Although variable-width fonts can be used, the fixed-width fonts provide a cleaner appearance. Fonts can be interactively selected using the XFONT function.
Listed below are a number of examples invoking XVIS. Assume that the variable FontName is a string that specifies a font name. Such a variable can be interactively selected by entering FontName = XFONT() within IDL.
XVIS
XVIS, /ALL_COLORS
XVIS, FONT=FontName
XVIS, FONT=FontName, /USE_AVAILABLE_COLORS
Once the program has been invoked, the main control window appears. Open a file using the Open... in the file menu and a window appears which displays the currently active image.