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Atmospheric Administration
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X Windows Requirements and Use

X Windows Requirements and Use


What kind of X Windows environment do I need to run Ferret?


A compilation of notes from various sources in the Ferret documentation

From the Users Guide:

Ferret runs on most Unix systems, and uses X windows for display.

When installing or updating Ferret, check the installation guide for your system, from the FerretDownloads pages for requirements and instructions regarding the x window and x server configuration.

To get graphical output from Ferret at your workstation, you must have the X Windows environment variable DISPLAY defined properly. Set the variable to point to the workstation screen where you want Ferret graphical outputdisplayed. In the example below graphics output will be sent to the screen of workstation anorak.

% setenv DISPLAY anorak:0.0

If you are running X windows on the same system where Ferret is running,the setting is just :0.0

% setenv DISPLAY :0.0


Notes for Windows Systems:

You must have a running X server.

The X display must be set for indexed color (a.k.a. PseudoColor) -- maximum 65K colors. This is relevant to MAC X software and to systems that have 3D graphics hardware installed.

If a graphics window that was obscured by another window appears to be fully or partially blank after the obscuring window is moved, or if the graphics in a window are drawn incorrectly after the window is resized,then try typing:

yes? set mode refresh

and redrawing the graphic.

Some items from the Ferret v4.90 Release notes:

Ferret displays colors correctly on X window servers configured to use a 24 bit color display. If you use such a display, note the following:

Ferret can run in batch mode -- without an X server. Invoke  batch mode by starting up Ferret with the -gif option:

ferret -gif

Ferret can also generate PostScript files without an X server.This is an experimental feature and not fully supported. If you wish to use this mode, start Ferret with the -batch option:

% ferret -batch <file>.ps

24 bit system support

You may have to click on a Ferret window to correctly display the colors in  that window.Other windows may change color once the Ferret window becomes active.Clicking on the windows that change color will restore their original color.

The X server must support multiple visuals, and at least one PseudoColor, or indexed, visual. Unfortunately, the X server available on most Linux machines only supports one visual at a time; Ferret will not work with 24 bit color displays on such machines.

GIF mode - GIF output without X windows Graphical output is buffered, and can be stored in a GIF file by executing the FRAME command. For example:

yes? frame/file=picture.gif

sends the stored graphical output from Ferret to the GIF file picture.gif.

Please note the following when using batch mode:

* Window resizing only works if the window is cleared before resizing the window. For instance:

yes? set window/clear/size=0.25
yes? set mode meta
yes? set window/new

will resize the window while

yes? set window/size=0.25/clear

will cause an error.

* Avoid metafile commands when running in batch mode.

* Don't create new Ferret windows when running without an X server.


PostScript mode - PostScript output without X windows, where <file> is the name of the output file. Note that the filename must end with ".ps".

Please note the following when using PostScript mode:

* The PostScript output will not be fully written to the output file until you exit from Ferret.

* Window sizing commands do not have any effect on PostScript output.

* Avoid metafile commands when running in PostScript mode.

* Don't create new Ferret windows when running without an X server.