Gnuplot Question:

This depends on the terminal type you use.

* X11 toolkits: You can use the terminal type fig and use the xfig drawing program to edit the plot afterwards. You can obtain the xfig program from its web site http://www.xfig.org. More information about the text-format used for fig can be found in the fig-package.

You may use the tgif terminal, which creates output suitable for reading within tgif (http://bourbon.cs.umd.edu:8001/tgif/), an interactive 2-D drawing tool under X11.

* You may use the svg terminal (scalable vector graphics), which can be further edited by a svg editor, e.g. Inkscape (http://www.inkscape.org), Sodipodi (http://sodipodi.sourceforge.net), Sketch (http://sketch.sourceforge.net) or Dia (http://www.lysator.liu.se/ alla/dia), or loaded into OpenOffice.org with an on-fly conversion into OO.o Draw primitives.

* PostScript or PDF output can be edited directly by tools such as Adobe Illustrator or Acrobat, or can be converted to a variety of other editable vector formats by the pstoedit package. Pstoedit is available at http://www.pstoedit.net.