Options related to the page setup are changed in the p)age submenu.
It is possible to over-plot data from one file on top of data from another using the ``plot n steps on top of each other'' option from the p)age submenu. Setting $n$ to a number greater than one means that the page is not changed until $n$ steps have been plotted. Following the prompts, it is possible to change the colour of all particles between steps and the graph markers used and plot an associated legend (see below). Note that this option can also be used in combination with a multiplot (see §??) -- for example plotting the density vs x and pressure vs x in separate panels, then with $n > 1$ all timesteps will be plotted in each panel).
When more than one timestep is plotted per page with different markers/colours, an additional legend can be plotted (turn this on in the le(g)end submenu, or when prompted whilst setting the "plot n steps on top of each other" option). The text for this legend is just the filename by default (if one timestep per file) or just something dull like 'step 1' (if more than one timestep per file).
To change the legend text, create a file called
legend in the working directory, with one label per line. The position of the legend can be changed either manually via the ``legend and title options'' in the p)age submenu, or by positioning the mouse in interactive mode and pressing 'G' (similar keys apply for moving plot titles and the legend for vector plots -- press 'h' in interactive mode for a full list).
Note that this is slightly different to ``plotting more than one dump file on the same panel''
Axes settings can be changed in the p)age submenu, by choosing ``axes options''. The options are as follows:
-4 : draw box and major tick marks only; -3 : draw box and tick marks (major and minor) only; -2 : draw no box, axes or labels; -1 : draw box only; 0 : draw box and label it with coordinates; 1 : same as AXIS=0, but also draw the coordinate axes (X=0, Y=0); 2 : same as AXIS=1, but also draw grid lines at major increments of the coordinates; 3 : draw box, ticks and numbers but no axes labels; 4 : same as AXIS=0, but with a second y-axis scaled and labelled differently 10 : draw box and label X-axis logarithmically; 20 : draw box and label Y-axis logarithmically; 30 : draw box and label both axes logarithmically.
Plot axes can be turned off by choosing ``axes options'' in the p)age submenu or by deleting them using the backspace key in interactive mode. See §?? for more details.
Axes labels and numbering can be turned off via the ``axes options'' option in the p)age submenu or by deleting them using the backspace key in interactive mode. See §?? for more details.
Logarithmic axes (that is where the quantity plotted is logged) can be set via the ``apply log or inverse transformations'' option in the l)imits submenu or simply by pressing 'l' with the cursor over the desired axis (or the colour bar) in interactive mode. By default the axes labels reads $log(x)$ and the number next to the axis is $-4$ when $x$ is 10$^-4$. Logarithmic axes labels (i.e., where the label reads $x$ and the number next to the axis is $10^-4$ with a logarithmic scale) can be specified by choosing the ``axes options'' option in the p)age submenu and setting the axes option to 10, 20 or 30 as necessary (see §?? for more details).
A second y axis can be added by selecting the axis=4 option in the ``axes option'' in the p)age submenu (see §??). This will prompt for the scaling and alternative label:
enter axis option ([-4:30], default=0): 4 enter scale factor for alternative y axis ([0.000:], default=1.000): 10.0 enter label for alternative y axis (default=""): y [other units]
The physical size of the viewing surface used for plotting can be changed via the ``change paper size'' option in the p)age submenu. This affects the size of the X-window (if plotted to the screen) and the size of .png or images generated (if plotted to these devices). Several preset options are provided or the paper size in x and y can be explicitly specified in inches or pixels.
The plotting page can be divided into panels using the ``subdivide page into panels'' option in the p)age submenu. Note that for multiple plots per page (i.e., nacross $×$ ndown $> 1$) a more limited interactive mode applies (basically because the data used for the plots is no longer stored in memory if there is more than one plot on the same page meaning that functionality such as selecting particles must be turned off).
Plots with the same $x-$ and $y-$ axes are tiled if the tiling option from the (p)age options menu (§??) is set. Tiling means that only one axis is shown where multiple plots share the same x or y axis and that the plots are placed as close to each other as possible. For rendered plots a shared colour bar is plotted which spans the full length of the page.
By default if the x and y axes are both spatial coordinates, the axes are scaled proportionately. This can be changed via the ``spatial dimensions have same scale'' option in the p)age submenu.
The character height used for axes, labels and legends can be changed via the p)age setup options submenu. Note that the character height is relative to the paper size (which can also be changed -- see §??).
The line width used for axes and text can be changed via the p)age submenu. Note that line width changes are not always obvious when plotting to an interactive device (e.g. an X-window) but influence non-interactive devices strongly.
The background and foreground colour of a plot can be changed vie the ``set foreground/background colours'' option in the p)age submenu. Note that the background colour setting has no effect on postscript devices (see §?? for more details).
By default, axes, legends and titles are plotted in the foreground colour (e.g. black). However if the plot itself is also largely black (e.g. when rendering or when lots of particles are plotted) it can be useful to overplot those parts of the axes and labelling which lie on top of the plotting surface in the background colour (e.g. white). A prompt for this is given when setting the ``set foreground/background colours'' option in the p)age submenu.
The prompt appears as follows:
---------------- page setup options ------------------- ... 9) set foreground/background colours enter option ([0:8], default=0):9 Enter background colour (by name, e.g. "black") (default=""):white Enter foreground colour (by name, e.g. "white") (default=""):black Overlaid (that is, drawn inside the plot borders) axis ticks, legend text and titles are by default plotted in the foreground colour [i.e., black]. Do you want to plot these in background colour [i.e., white] instead ? (default=no):y
In the above I have selected a background colour of white, a foreground colour of black. Answering yes to the last question means that those parts of the axes which lie on top of the viewing surface (and any labels) will be plotted in white (the background colour) instead of the foreground colour (black).