Devices

Three kinds of graphic devices are known by funct : a X11-window, Postscript files and PNG files. Postscript files are created by the command defgraph_PS... and PNG files by the command defgraph_PNG.... These commands will create the files (cf. 3.7). For example,

defgraph_PNG W2 imag.png 600 350

will create a PNG image of width 600 and height 350 named W2 that will be stored in the file imag.png in the result directory. The name W2 will be used in funct to denote this image. The X11-window will be created if it is not present each time the object X is invoked. For example, the command

 - funct -> clear X

will clear the X11 window if it is present, and create a blank one if not. So the name X is reserved for the X11 window.

There are two ways of drawing on a graphic object :

1. By using absolute coordinates (i.e. pixels). This is done by the commands
   graphplot... and graphline...
2. By using frames. This will determine a rectangular region in the windows and plots using frames will be possible only in this region. In this case also the coordinates are considered relatively to the extremal values of $x$ and $y$ for the frame (cf. 3.5.3).