The 3 first commands determines the kind of plots that will be performed by the plotting commands. The size of the plot will depend on the contexts CX and CY (in centimetres). ROTATE exchange X and Y axes on the plotter such that the drawings are rotated on the sheet. Two kinds of plotter can be connected to Gifa : a HP-GL plotter (usual for pen plotter) or a Postscript (usual for laser printers). The plotter is chosen with the PLOTTER command, you can tell for which plotter the program is currently connected to with the CONFIG command.
The PLOT command will plot whatever is currently on the screen. In 2D, the plot will be strictly equivalent to what is displayed by the CDISP2D mode; in 1D, the plot will be equivalent to what is displayed, but in a CX x CY format; in 3D the last extracted plane, as seen on the 2D display will be plotted.
PEN permits to change the active pen. In HP-GL, this is the number of the pen; in Postscript, 8 kind of lines are available :
PCOLOR permits to choose a colour when plotting on a colour Postscript printer. Only the 8 basic Gifa colours are thus available. If you wish to use more exotic colours, you should edit the plot file itself.
PAGE will send the page to the plotter, and eject the page on a plotter.
PLOTOFFSET is the constant offset on x and y axes which is applied for each plots. Each plotting command will see the point at coordinates 0;0 as actually being offsetted from the true 0;0 of the paper with the PLOTOFFSET values. PLOTOFFSET permits to stack different plots on a single sheet.
TITLE will plot the text following the command at coordinates x=0, y=CY+1.
PLOT? will prompt you for all the parameters currently used for plotting.
All these commands will prompt you for an output parameter, entering *PL (or *PLOTTER) will output the plot to the plotter. Entering a file-name will create a file containing the graphic commands for the plotter. If you send several plot commands to the same file, the following commands will be appended to the first one in the plot file, thus permitting to make composite plots on a single sheet. The PAGE command appends the order for page change, send the file to the plotter port, and makes Gifa "forget" about the plot file, thus plotting again on that file will erase the file and start a new plot. FORGET will only makes Gifa forget the file, without sending it to the plotter.
The plot file can also be sent to the plotter by typing at the operating system level :
$gifaplot plot_file plotter_type ( VMS or UNIX)
with plotter_type being either postscript or HP-GL, depending on the type of plot file you have created.
When working in postscript, it is very convenient to use a Display Postscript program to monitor the state of the current plot file.
The first command permits to draw an horizontal and/or vertical axis on the current plot. The graduation is done according to the current values of SPECW and OFFSET. PLOTAXIS? permits to configure the axes drawn by PLOTAXIS. GRID permits to draw a grid of CX by CY on the current plot, it will use the axes determined by PLOTAXIS?. Check the macros plotn and nice_plot for examples of these functions.
STPL will generate a stack plot either on the screen (*S), on the plotter (*PL) or in a file. The stack-plot depends on the value of the following contexts :
CX : length in centimetres of a line.
CY : maximum height of a peak in centimetres.
SCALE : scaling applied to the data before plotting, if scale=1 then the larger peak on the surface will be CY high, if scale>1 then clipping will occur.
STDY : each new line is offsetted by STDY centimetres in the Y axis.
STSKIP : every STSKIP line of the data-set will be drawn.
STSHIFT : each new line will be shifted right by STSHIFT points, if negative then the shift is done on the left. (May be fractional).
STSKEW : determines how the horizontal lines are skewed during plot, (if negative skewed to the left and to the right if positive.
STPL? permits to check all the parameters in one command.
On screen stack plots are currently limited to 256x128 points (larger plots generally crashes the graphic).