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X Windows Requirements and Use

X Windows Requirements and Use

Question:

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

Explanation:

A compilation of notes from various sourcesin the Ferret documentation

From the Users Guide:

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

When installing or updating Ferret, check the installation guide foryour system, from theFerretDownloads pages for requirements and instructions regarding the x windowand x server configuration.

To get graphical output from Ferret at your workstation, you must havethe X Windows environment variable DISPLAY defined properly. Set the variableto point to the workstation screen where you want Ferret graphical outputdisplayed. In the example below graphics output will be sent to the screenof 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. Thisis relevant to MAC X software and to systems that have 3D graphicshardware installed.

If a graphics window that was obscured by another window appears tobe fully or partially blank after the obscuring window is moved, or ifthe 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:

  • 24 bit system support
  • Ferret displays colors correctly on X window servers configuredto use a 24 bit color display. If you use such a display, note the following:

    • You may have to click on a Ferret window to correctly display the colorsin that window.
    • Other windows may change color once the Ferret window becomes active. Clickingon 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 Linuxmachines only supports one visual at a time; Ferret will not work with24 bit color displays on such machines.
  • GIF mode - GIF output without X windows
  • Ferret can now run in batch mode -- without an X server. Invokebatch mode by starting up Ferret with the -gif option:

ferret -gif

Graphical output is buffered, and can be stored in a GIF file by executingthe 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 thewindow. For instance:
yes? set window/clear/size=0.25

will resize the window while

yes? set window/size=0.25/clear

will cause an error.

  • Avoid metafile commands when running in batch mode. In particular,
  • yes? set mode meta

    may cause problems.

  • Don't create new Ferret windows when running without an X server. The followingcommand:
  • yes? set window/new

    will result in an error.

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

    % ferret -batch <file>.ps

    where <file> is the name of the output file. Note that the filenamemust end with ".ps".

    Please note the following when using PostScript mode:

    • The PostScript output will not be fully written to the output file untilyou 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. The followingcommand:
    yes? set window/new

    will result in an error.