University of Minnesota Supercomputing Institute

Xfig

One of the main reasons for using xfig its compatibility with LaTeX. By using xfig, you can create pictures composed of lines, rectangles, circles, ellipses, splines and more, and then add text whose font will match that of a LaTeX document.

Xfig can also be used to annotate encapsulated postscript, X11 bit- and pixmap, GIF and JPEG images. Again the font can match the font of a LaTeX document.

Annotating Images

For more information on image annotation using of xfig, contact the graphics support coordinator, Barry Schaudt at schaudt@msi.umn.edu

Annotating Postscript Images

There are basically two types of PostScript files: Images and Objects. To compare the two, we will discuss how a line is stored in each. As an object, the endpoints of the line are stored. It is up to the PostScript interperter, such as Ghostview or a printer, to actually draw the line. When a line is stored as an ojbect, it is easy to modify the line. Scaling is a typical modification.

When a line is stored as an image, it is stored pixel by pixel along with the rest of the image. The PostScript interperter cannot distinguish the line from any other set of pixels. It isn't easy to modify an image. When an image is expanded, pixels must be interpolated. When an image is shrunk, pixels must be thrown away. Therefore, scaling an image often results in a loss of resolution and quality.

When xfig reads in a PostScript file, it converts it to a PostScript image. Lines, text and such are converted to pixels. This conversion often results in a loss of quality. If this quality is not acceptable, use other annotation tools: tgif or showcase. The tradeoff: These tools are not able to produce the fonts used in LaTeX. In this case, you will have to decide which is more important, the same font or image quality.

Use with LaTeX

For more information on using the output of xfig in a LaTeX document, contact the graphics support coordinator, Barry Schaudt at schaudt@msi.umn.edu

Last modified: Summer 1996