\chapter {PLPLOT Subroutine Reference} \label{reference} All the PLPLOT subroutines are listed below in alphabetical order. \bname{pladv(sub)}\label{pladv} \addcontentsline{toc}{subsection}{pladv} \descr{Advances to the next subpage if {\tt sub=0} or to the specified subpage if {\tt sub} is non-zero. This routine is called automatically (with {\tt sub=0}) by {\tt plenv}, but if {\tt plenv} is not used, {\tt pladv} must be called after {\tt plstar} but before defining the viewport.} \argu {{\tt sub} (PLINT, input)}{Specifies the subpage number (starting from 1 in the top left corner and increasing along the rows) to which to advance. Set to zero to advance to the next subpage.} \bname{plbeg(dev,nx,ny)}\label{plbeg} \addcontentsline{toc}{subsection}{plbeg} \descr{Alternative to {\tt plstar} for initializing the plotting package. The device number of the desired output device must be supplied as an argument. The mapping from device numbers to devices varies from one implementation to another, and so use of {\tt plstar} which prompts for the device type is recommended. The device codes are the same as those printed out by {\tt plstar}. This routine also divides the output device into {\tt nx} by {\tt ny} sub-pages, each of which may be used independently. The subroutine {\tt pladv} is used to advance from one subpage to the next.} \argu {{\tt dev} (PLINT, input)}{Device number of the required output device.} \argu {{\tt nx} (PLINT, input)}{Number of subpages to divide output page in the horizontal direction.} \argu {{\tt ny} (PLINT, input)}{Number of subpages to divide output page in the vertical direction.} \bname{plbin(nbin,x,y,cen)}\label{plbin} \addcontentsline{toc}{subsection}{plbin} \descr{Plots a histogram consisting of {\tt n} bins. The value associated with the {\tt i}'th bin is placed in {\tt x[i]}, and the number of points in the bin is placed in {\tt y[i]}. For proper operation, the values in {\tt x[i]} must form a strictly increasing sequence. If {\tt centre} is false, {\tt x[i]} is the left-hand edge of the {\tt i'th} bin, and if {\tt centre} is true, the bin boundaries are placed midway between the values in the {\tt x}~array. Also see {\tt plhist} for drawing histograms from unbinned data.} \argu {{\tt nbin} (PLINT, input)}{Number of bins (i.e., number of values in $x$ and $y$ arrays.)} \argu {{\tt x} (PLFLT *, input)}{Pointer to array containing values associated with bins. These must form a strictly increasing sequence.} \argu {{\tt y} (PLFLT *, input)}{Pointer to array containing number of points in bin. This is a PLFLT (instead of PLINT) array so as to allow histograms of probabilities, etc.} \argu {{\tt cen} (PLINT, input)}{Indicates whether the values in {\tt x} represent the lower bin boundaries ({\tt cen=0}) or whether the bin boundaries are to be midway between the {\tt x} values ({\tt cen=1}). If the values in {\tt x} are equally spaced and {\tt cen=1}, the values in {\tt x} are the centre values of the bins.} \bname{plbox(xopt,xtick,nxsub,yopt,ytick,nysub)}\label{plbox} \addcontentsline{toc}{subsection}{plbox} \descr{Draws a box around the currently defined viewport, and labels it with world coordinate values appropriate to the window. Thus {\tt plbox} should only be called after defining both viewport and window. The character strings {\tt xopt} and {\tt yopt} specify how the box should be drawn as described below. If ticks and/or subticks are to be drawn for a particular axis, the tick intervals and number of subintervals may be specified explicitly, or they may be defaulted by setting the appropriate arguments to zero.} \argu {{\tt xopt} (char *, input)}{Pointer to character string specifying options for horizontal axis. The string can include any combination of the following letters (upper or lower case) in any order: \begin{itemize} \item{{\tt a :}} Draws axis, X-axis is horizontal line {\tt y=0}, and Y-axis is vertical line {\tt x=0}. \item{{\tt b :}} Draws bottom (X) or left (Y) edge of frame. \item{{\tt c :}} Draws top (X) or right (Y) edge of frame. \item{{\tt g :}} Draws a grid at the major tick interval. \item{{\tt i :}} Inverts tick marks, so they are drawn outwards, rather than inwards. \item{{\tt l :}} Labels axis logarithmically. This only affects the labels, not the data, and so it is necessary to compute the logarithms of data points before passing them to any of the drawing routines. \item{{\tt m :}} Writes numeric labels at major tick intervals in the unconventional location (above box for X, right of box for Y). \item{{\tt n :}} Writes numeric labels at major tick intervals in the conventional location (below box for X, left of box for Y). \item{{\tt s :}} Enables subticks between major ticks, only valid if {\tt t} is also specified. \item{{\tt t :}} Draws major ticks. \end{itemize}} \argu {{\tt xtick} (PLFLT, input)}{World coordinate interval between major ticks on the x~axis. If it is set to zero, PLPLOT automatically generates a suitable tick interval.} \argu {{\tt nxsub} (PLINT, input)}{Number of subintervals between major x~axis ticks for minor ticks. If it is set to zero, PLPLOT automatically generates a suitable minor tick interval.} \argu {{\tt yopt} (char *, input)}{Pointer to character string specifying options for vertical axis. The string can include any combination of the letters defined above for {\tt xopt}, and in addition may contain: \begin{itemize} \item{{\tt v }}{: Write numeric labels for vertical axis parallel to the base of the graph, rather than parallel to the axis.} \end{itemize} } \argu {{\tt ytick} (real, input)}{World coordinate interval between major ticks on the y~axis. If it is set to zero, PLPLOT automatically generates a suitable tick interval.} \argu {{\tt nysub} (PLINT, input)}{Number of subintervals between major y~axis ticks for minor ticks. If it is set to zero, PLPLOT automatically generates a suitable minor tick interval.} \bname{ \begin{tabular}{l@{\strut}l} plbox3(&xopt,xlabel,xtick,nxsub,yopt,ylabel,ytick,nysub,\\ &zopt,zlabel,ztick,nzsub) \end{tabular} } \label{plbox3} \addcontentsline{toc}{subsection}{plbox3} \descr{Draws axes, numeric and text labels for a three-dimensional surface plot. See Section \ref{threed} on page \pageref{threed} for a more complete description of three-dimensional plotting.} \argu {{\tt xopt} (char *, input)}{Pointer to character string specifying options for the x~axis. The string can include any combination of the following letters (upper or lower case) in any order: \begin{itemize} \item{{\tt b :}} Draws axis at base, at height {\tt z=zmin} where {\tt zmin} is defined by call to {\tt plw3d}. This character must be specified in order to use any of the other options. \item{{\tt i :}} Inverts tick marks, so they are drawn downwards, rather than upwards. \item{{\tt l :}} Labels axis logarithmically. This only affects the labels, not the data, and so it is necessary to compute the logarithms of data points before passing them to any of the drawing routines. \item{{\tt n :}} Writes numeric labels at major tick intervals. \item{{\tt s :}} Enables subticks between major ticks, only valid if {\tt t} is also specified. \item{{\tt t :}} Draws major ticks. \item{{\tt u :}} If this is specified, the text label for the axis is written under the axis. \end{itemize} } \argu {{\tt xlabel} (char *, input)}{Pointer to character string specifying text label for the x~axis. It is only drawn if {\tt u} is in the {\tt xopt} string.} \argu {{\tt xtick} (PLFLT, input)}{World coordinate interval between major ticks on the x~axis. If it is set to zero, PLPLOT automatically generates a suitable tick interval.} \argu {{\tt nxsub} (PLINT, input)}{Number of subintervals between major x~axis ticks for minor ticks. If it is set to zero, PLPLOT automatically generates a suitable minor tick interval.} \argu {{\tt yopt} (char *, input)}{Pointer to character string specifying options for the y~axis. The string is interpreted in the same way as {\tt xopt}.} \argu {{\tt ylabel} (char *, input)}{Pointer to character string specifying text label for the y~axis. It is only drawn if {\tt u} is in the {\tt yopt} string.} \argu {{\tt ytick} (PLFLT, input)}{World coordinate interval between major ticks on the y~axis. If it is set to zero, PLPLOT automatically generates a suitable tick interval.} \argu {{\tt nysub} (PLINT, input)}{Number of subintervals between major y~axis ticks for minor ticks. If it is set to zero, PLPLOT automatically generates a suitable minor tick interval.} \argu {{\tt zopt} (char *, input)}{Pointer to character string specifying options for the z~axis. The string can include any combination of the following letters (upper or lower case) in any order: \begin{itemize} \item{{\tt b :}} Draws z~axis to the left of the surface plot. \item{{\tt c :}} Draws z~axis to the right of the surface plot. \item{{\tt d :}} Draws grid lines parallel to the x-y plane behind the figure. These lines are not drawn until after {\tt plot3d} or {\tt plmesh} are called because of the need for hidden line removal. \item{{\tt i :}} Inverts tick marks, so they are drawn away from the centre. \item{{\tt l :}} Labels axis logarithmically. This only affects the labels, not the data, and so it is necessary to compute the logarithms of data points before passing them to any of the drawing routines. \item{{\tt m :}} Writes numeric labels at major tick intervals on the right-hand verical axis. \item{{\tt n :}} Writes numeric labels at major tick intervals on the left-hand verical axis. \item{{\tt s :}} Enables subticks between major ticks, only valid if {\tt t} is also specified. \item{{\tt t :}} Draws major ticks. \item{{\tt u :}} If this is specified, the text label is written beside the left-hand axis. \item{{\tt v :}} If this is specified, the text label is written beside the right-hand axis. \end{itemize} } \argu {{\tt zlabel} (char *, input)}{Pointer to character string specifying text label for the z~axis. It is only drawn if {\tt u} or {\tt v} are in the {\tt zopt} string.} \argu {{\tt ztick} (PLFLT, input)}{World coordinate interval between major ticks on the z~axis. If it is set to zero, PLPLOT automatically generates a suitable tick interval.} \argu {{\tt nzsub} (PLINT, input)}{Number of subintervals between major z~axis ticks for minor ticks. If it is set to zero, PLPLOT automatically generates a suitable minor tick interval.} \bname{plclr()}\label{plclr} \addcontentsline{toc}{subsection}{plclr} \descr{Clears the graphics screen of an interactive device, or ejects a page on a plotter.} \bname{plcol(color)}\label{plcol} \addcontentsline{toc}{subsection}{plcol} \descr{Sets the color for subsequent lines.} \argu {{\tt color} (PLINT, input)}{Integer representing the color.} \bname{plcont(z,nx,ny,kx,lx,ky,ly,clevel,nlevel,pltr)}\label{plcont} \addcontentsline{toc}{subsection}{plcont} \descr{Draws a contour plot of the data in {\tt z[nx][ny]}, using the {\tt nlevel} contour levels specified by {\tt clevel}. Only the region of the array from {\tt kx} to {\tt lx} and from {\tt ky} to {\tt ly} is plotted out. A transformation routine {\tt tr} is used to map indicies within the array to the world coordinates (see Section \ref{contour} on page \pageref{contour}). } \argu {{\tt z} (PLFLT *, input)} {Pointer to a two-dimensional array containing data to be contoured.} \argu {{\tt nx, ny} (PLINT, input)} {Physical dimensions of array {\tt z}.} \argu {{\tt kx, lx} (PLINT, input)} {Range of {\tt x} indicies to consider.} \argu {{\tt ky, ly} (PLINT, input)} {Range of {\tt y} indicies to consider.} \argu {{\tt clevel} (PLFLT *, input)} {Pointer to array specifying levels at which to draw contours.} \argu {{\tt nlevel} (PLINT, input)} {Number of contour levels to draw.} \argu {{\tt pltr} (void *,input)} {Pointer to function that defines transformation between indicies in array {\tt z} and the world coordinates. The function should have the form \name{pltr(x,y,tx,ty)} \argu {{\tt x, y} (PLFLT, input)}{ Specifies the position in the array through which the contour runs in terms of the array indicies.} \argu {{\tt tx, ty} (PLFLT *, output)}{Pointers to the world coordinates corresponding to the point {\tt (x,y)}.} } A transformation function {\tt xform} is provided for simple linear mappings. See Section \ref{contour} for information. \bname{plend()}\label{plend} \addcontentsline{toc}{subsection}{plend} \descr{Ends a plotting session, tidies up all the output files, switches interactive devices back into text mode and frees up any memory that was allocated. Must be called before end of program.} \bname{plenv(xmin,xmax,ymin,ymax,just,axis)}\label{plenv} \addcontentsline{toc}{subsection}{plenv} \descr{Sets up plotter environment for simple graphs by calling {\tt pladv} and setting up viewport and window to sensible default values. {\tt plenv} leaves enough room around most graphs for axis labels and a title. When these defaults are not suitable, use the individual routines {\tt plvspa} or {\tt plvpor} for setting up the viewport, {\tt plwind} for defining the window, and {\tt plbox} for drawing the box.} \argu {{\tt xmin} (PLFLT, input)}{Value of~x at left-hand edge of window.} \argu {{\tt xmax} (PLFLT, input)}{Value of~x at right-hand edge of window.} \argu {{\tt ymin} (PLFLT, input)}{Value of~y at bottom edge of window.} \argu {{\tt ymax} (PLFLT, input)}{Value of~y at top edge of window.} \argu {{\tt just} (PLINT, input)}{If {\tt just=0}, the x~and~y axes are scaled independently to use as much of the screen as possible, but if {\tt just=1}, the scales of the x~and~y axes are made equal.} \argu {{\tt axis} (PLINT, input)}{Controls drawing of the box around the plot: \begin{itemize} \item{-2}: No box or annotation. \item{-1}: Draw box only. \item{0}: Draw box, labelled with coordinate values around edge. \item{1}: In addition to box and labels, draw the two axes {\tt x=0} and {\tt y=0}. \item{2}: As for {\tt axis=1}, but also draw a grid at the major tick interval. \item{10}: Logarithmic x axis, linear y axis. \item{11}: Logarithmic x axis, linear y axis and draw line {\tt y=0}. \item{20}: Linear x axis, logarithmic y axis. \item{21}: Linear x axis, logarithmic y axis and draw line {\tt x=0}. \item{30}: Logarithmic x and y axes. \end{itemize} } \bname{plerrx(n,xmin,xmax,y)}\label{plerrx} \addcontentsline{toc}{subsection}{plerrx} \descr{Draws a set of {\tt n} horizontal error bars, the {\tt i}'th error bar extending from {\tt xmin[i]} to {\tt xmax[i]} at y~coordinate {\tt y[i]}. The terminals of the error bar are of length equal to the minor tick length (settable using {\tt plsmin}).} \argu {{\tt n} (PLINT, input)}{Number of error bars to draw.} \argu {{\tt xmin} (PLFLT *, input)}{Pointer to array with x~coordinates of left-hand endpoint of error bars.} \argu {{\tt xmax} (PLFLT *, input)}{Pointer to array with x~coordinates of right-hand endpoint of error bars.} \argu {{\tt y} (PLFLT *, input)}{Pointer to array with y~coordinates of error bar.} \bname{plerry(n,x,ymin,ymax)}\label{plerry} \addcontentsline{toc}{subsection}{plerry} \descr{Draws a set of {\tt n} vertical error bars, the {\tt i}'th error bar extending from {\tt ymin[i]} to {\tt ymax[i]} at x~coordinate {\tt x[i]}. The terminals of the error bar are of length equal to the minor tick length (settable using {\tt plsmin}).} \argu {{\tt n} (PLINT, input)}{Number of error bars to draw.} \argu {{\tt x} (PLFLT *, input)}{Pointer to array with x~coordinates of error bars.} \argu {{\tt ymin} (PLFLT *, input)}{Pointer to array with y~coordinates of lower endpoint of error bars.} \argu {{\tt ymax} (PLFLT *, input)}{Pointer to array with y~coordinate of upper endpoint of error bar.} \bname{plexit(message)}\label{plexit} \addcontentsline{toc}{subsection}{plexit} \descr{This routine is called in case an error is encountered during execution of a PLPLOT routine. It prints the error message, tries to release allocated resources, calls {\tt pl\_exit} and then exits. If cleanup needs to be done in the driver program then the user may want to supply his/her own version of {\tt pl\_exit}.} \argu {{\tt message} (char *, input)}{Error message.} \bname{pl\_exit()}\label{plxexit} \addcontentsline{toc}{subsection}{pl\_exit} \descr{This routine does an immediate return. It is called by {\tt plexit} and is intended to be replaced by a user routine of the same name so that any user allocated resources can be released in the case of an error. See {\tt plexit} above.} \bname{plfill(n,x,y)}\label{plfill} \addcontentsline{toc}{subsection}{plfill} \descr{Fills the polygon defined by the {\tt n} points {\tt (x[i],y[i])} using the pattern defined by {\tt plpsty} or {\tt plpat}. The routine will automatically close the polygon between the last and first vertices. If multiple closed polygons are passed in {\tt x} and {\tt y} then {\tt plfill} will fill in between them.} \argu {{\tt n} (PLINT, input)}{Number of vertices in polygon.} \argu {{\tt x} (PLFLT *, input)}{Pointer to array with x~coordinates of vertices.} \argu {{\tt y} (PLFLT *, input)}{Pointer to array with y~coordinates of vertices.} \bname{plfont(font)}\label{plfont} \addcontentsline{toc}{subsection}{plfont} \descr{Sets the default character font for subsequent character drawing. Also affects symbols produced by {\tt plpoin}.} \argu {{\tt font} (PLINT, input)}{Specifies the font: \begin{itemize} \item{1}: Normal font (simplest and fastest) \item{2}: Roman font \item{3}: Italic font \item{4}: Script font \end{itemize} } \bname{plfontld(set)}\label{plfontld} \addcontentsline{toc}{subsection}{plfontld} \descr{Sets the character set to use for subsequent character drawing.} \argu {{\tt set} (PLINT, input)}{Specifies the character set to load: \begin{itemize} \item{0}: Standard character set \item{1}: Extended character set \end{itemize} } \bname{plgra()}\label{plgra} \addcontentsline{toc}{subsection}{plgra} \descr{Sets an interactive device to graphics mode, used in conjunction with {\tt pltext} to allow graphics and text to be interspersed.} \bname{plgspa(xmin,xmax,ymin,ymax)}\label{plgspa} \addcontentsline{toc}{subsection}{plgspa} \descr{Gets the size of the current subpage in millimetres measured from the bottom left hand corner of the output device page or screen. Can be used in conjunction with {\tt plsvpa} for setting the size of a viewport in absolute coordinates (millimetres).} \argu {{\tt xmin} (PLFLT *, output)}{Pointer to variable with position of left hand edge of subpage in millimetres.} \argu {{\tt xmax} (PLFLT *, output)}{Pointer to variable with position of right hand edge of subpage in millimetres.} \argu {{\tt ymin} (PLFLT *, output)}{Pointer to variable with position of bottom edge of subpage in millimetres.} \argu {{\tt ymax} (PLFLT *, output)}{Pointer to variable with position of top edge of subpage in millimetres.} \bname{plhist(n,data,datmin,datmax,nbin,oldwin)}\label{plhist} \addcontentsline{toc}{subsection}{plhist} \descr{Plots a histogram from {\tt n} data points stored in the array {\tt data}. This routine bins the data into {\tt nbin} bins equally spaced between {\tt datmin} and {\tt datmax}, and calls {\tt plbin} to draw the resulting histogram. Parameter {\tt oldwin} allows the histogram either to be plotted in an existing window or causes {\tt plhist} to call {\tt plenv} with suitable limits before plotting the histogram.} \argu {{\tt n} (PLINT, input)}{Number of data points.} \argu {{\tt data} (PLFLT *, input)}{Pointer to array with values of the {\tt n} data points.} \argu {{\tt datmin} (PLFLT, input)}{Left-hand edge of lowest-valued bin.} \argu {{\tt datmax} (PLFLT, input)}{Right-hand edge of highest-valued bin.} \argu {{\tt nbin} (PLINT, input)}{Number of (equal-sized) bins into which to divide the interval {\tt xmin} to {\tt xmax}.} \argu {{\tt oldwin} (PLINT, input)}{If one, the histogram is plotted in the currently-defined window, and if zero, {\tt plenv} is called automatically before plotting.} \bname{pljoin(x1,y1,x2,y2)}\label{pljoin} \addcontentsline{toc}{subsection}{pljoin} \descr{Joins the point {\tt (x1,y1)} to {\tt (x2,y2)}.} \argu {{\tt x1} (PLFLT, input)}{x~coordinate of first point.} \argu {{\tt y1} (PLFLT, input)}{y~coordinate of first point.} \argu {{\tt x2} (PLFLT, input)}{x~coordinate of second point.} \argu {{\tt y2} (PLFLT, input)}{y~coordinate of second point.} \bname{pllab(xlabel,ylabel,tlabel)}\label{pllab} \addcontentsline{toc}{subsection}{pllab} \descr{Routine for writing simple labels. Use {\tt plmtex} for more complex labels.} \argu {{\tt xlabel} (char *, input)}{Label for horizontal axis.} \argu {{\tt ylabel} (char *, input)}{Label for vertical axis.} \argu {{\tt tlabel} (char *, input)}{Title of graph.} \bname{plline(n,x,y)}\label{plline} \addcontentsline{toc}{subsection}{plline} \descr{Draws {\tt n-1} line segments joining points {\tt (x[i],y[i])}.} \argu {{\tt n} (PLINT, input)}{Number of points to join.} \argu {{\tt x} (PLFLT *, input)}{Pointer to array with x~coordinates of points.} \argu {{\tt y} (PLFLT *, input)}{Pointer to array with y~coordinates of points.} \bname{pllsty(n)}\label{pllsty} \addcontentsline{toc}{subsection}{pllsty} \descr {This sets the line style according to one of eight predefined patterns (also see {\tt plstyl}).} \argu {{\tt n} (PLINT, input)}{Integer value between 1 and 8.} \bname{plmesh(x,y,z,ly,nx,ny,opt)}\label{plmesh} \addcontentsline{toc}{subsection}{plmesh} \descr{Plots a surface mesh within the environment set up by {\tt plw3d}. The surface is defined by the two-dimensional array {\tt z[][ly]}, the point {\tt z[i][j]} being the value of the function at {\tt (x[i],y[j])}. Note that the points in arrays {\tt x} and {\tt y} do not need to be equally spaced, but must be stored in ascending order. The parameter {\tt opt} controls the way in which the surface is displayed. See Section \ref{threed} on page \pageref{threed} for further details.} \argu {{\tt x} (PLFLT *, input)}{Pointer to set of x~coordinate values at which the function is evaluated.} \argu {{\tt y} (PLFLT *, input)}{Pointer to set of y~coordinate values at which the function is evaluated.} \argu {{\tt z} (PLFLT *, input)}{Pointer to two dimensional array with set of function values.} \argu {{\tt ly} (PLINT, input)}{Declared second dimension of {\tt z}~array.} \argu {{\tt nx} (PLINT, input)}{Number of {\tt x}~values at which function is evaluated.} \argu {{\tt ny} (PLINT, input)}{Number of {\tt y}~values at which function is evaluated.} \argu {{\tt opt} (PLINT, input)}{Determines the way in which the surface is represented: \begin{itemize} \item{1}: Lines are drawn showing {\tt z} as a function of {\tt x} for each value of {\tt y[j]}. \item{2}: Lines are drawn showing {\tt z} as a function of {\tt y} for each value of {\tt x[i]}. \item{3}: Network of lines is drawn connecting points at which function is defined. \end{itemize} } \bname{plmtex(side,disp,pos,just,text)}\label{plmtex} \addcontentsline{toc}{subsection}{plmtex} \descr{Writes text at a specified position relative to the viewport boundaries. Text may be written inside or outside the viewport, but is clipped at the subpage boundaries. The reference point of a string lies along a line passing through the string at half the height of a capital letter. The position of the reference point along this line is determined by {\tt just}, and the position of the reference point relative to the viewport is set by {\tt disp} and {\tt pos}.} \argu {{\tt side} (char *, input)}{Specifies the side of the viewport along which the text is to be written. The string must be one of: \begin{itemize} \item{b}: Bottom of viewport. \item{l}: Left of viewport, text written parallel to edge. \item{lv}: Left of viewport, text written at right angles to edge. \item{r}: Right of viewport, text written parallel to edge. \item{rv}: Right of viewport, text written at right angles to edge. \item{t}: Top of viewport. \end{itemize} } \argu {{\tt disp} (PLFLT, input)}{Position of the reference point of string, measured outwards from the specified viewport edge in units of the current character height. Use negative {\tt disp} to write within the viewport.} \argu {{\tt pos} (PLFLT, input)}{Position of the reference point of string along the specified edge, expressed as a fraction of the length of the edge.} \argu {{\tt just} (PLFLT, input)}{Specifies the position of the string relative to its reference point. If {\tt just=0}, the reference point is at the left and if {\tt just=1}, it is at the right of the string. Other values of {\tt just} give intermediate justifications.} \argu {{\tt text} (char *, input)}{The string to be written out.} \bname{plot3d(x,y,z,ly,nx,ny,opt,side)}\label{plot3d} \addcontentsline{toc}{subsection}{plot3d} \descr{Plots a three dimensional surface plot within the environment set up by {\tt plw3d}. The surface is defined by the two-dimensional array {\tt z[][ly]}, the point {\tt z[i][j]} being the value of the function at {\tt (x[i],y[j])}. Note that the points in arrays {\tt x} and {\tt y} do not need to be equally spaced, but must be stored in ascending order. The parameter {\tt opt} controls the way in which the surface is displayed. See Section \ref{threed} on page \pageref{threed} for further details.} \argu {{\tt x} (PLFLT *, input)}{Pointer to set of x~coordinate values at which the function is evaluated.} \argu {{\tt y} (PLFLT *, input)}{Pointer to set of y~coordinate values at which the function is evaluated.} \argu {{\tt z} (PLFLT *, input)}{Pointer to two dimensional array with set of function values.} \argu {{\tt ly} (PLINT, input)}{Declared second dimension of {\tt z}~array.} \argu {{\tt nx} (PLINT, input)}{Number of {\tt x}~values at which function is evaluated.} \argu {{\tt ny} (PLINT, input)}{Number of {\tt y}~values at which function is evaluated.} \argu {{\tt opt} (PLINT, input)}{Determines the way in which the surface is represented: \begin{itemize} \item{1}: Lines are drawn showing {\tt z} as a function of {\tt x} for each value of {\tt y[j]}. \item{2}: Lines are drawn showing {\tt z} as a function of {\tt y} for each value of {\tt x[i]}. \item{3}: Network of lines is drawn connecting points at which function is defined. \end{itemize} } \argu {{\tt side} (PLINT, input)}{Flag to indicate whether or not ``sides'' should be draw on the figure. If {\tt side=0} no sides are drawn, otherwise the sides are drawn.} \bname{plpat(nlin,inc,del)}\label{plpat} \addcontentsline{toc}{subsection}{plpat} \descr{Sets the area fill pattern. The pattern consists of 1 or 2 sets of parallel lines with specified inclinations and spacings. The arguments to this routine are the number of sets to use (1 or 2) followed by two pointers to integer arrays (of 1 or 2 elements) specifying the inclinations in tenths of a degree and the spacing in micrometers. (also see {\tt plpsty})} \argu{{\tt nlin} (PLINT, input)}{Number of sets of lines making up the pattern, either 1 or 2.} \argu{{\tt inc} (PLINT *, input)}{Pointer to array with {\tt nlin} elements. Specifies the line inclination in tenths of a degree. (Should be between -900 and 900).} \argu{{\tt del} (PLINT *, input)}{Pointer to array with {\tt nlin} elements. Specify the spacing in micrometers between the lines making up the pattern.} \bname{plpoin(n,x,y,code)}\label{plpoin} \addcontentsline{toc}{subsection}{plpoin} \descr{Marks out a set of {\tt n} points at positions {\tt (x(i),y(i))}, using the symbol defined by {\tt code}. If {\tt code} is between 32 and 127, the symbol is simply the printable ASCII character in the default font.} \argu {{\tt n} (PLINT, input)}{Number of points to be marked.} \argu {{\tt x} (PLFLT *, input)}{Pointer to array with set of x~coordinate values for the points.} \argu {{\tt y} (PLFLT *, input)}{Pointer to array with set of y~coordinate values for the points.} \argu {{\tt code} (PLINT, input)}{Code number for the symbol to be plotted.} \bname{plprec(set,prec)}\label{plprec} \addcontentsline{toc}{subsection}{plprec} \descr {Sets the number of places after the decimal point in numeric labels.} \argu {{\tt set} (PLINT, input)}{ If {\tt set} is equal to 0 then PLPLOT automatically determines the number of places to use after the decimal point in numeric labels (like those used to label axes). If {\tt set} is 1 then {\tt prec} sets the number of places.} \argu {{\tt prec} (PLINT, input)}{The number of characters to draw after the decimal point in numeric labels.} \bname{plpsty(n)}\label{plpsty} \addcontentsline{toc}{subsection}{plpsty} \descr{Select one of eight predefined area fill patterns to use. (also see {\tt plpat})} \argu {{\tt n} (PLINT *, input)}{The desired pattern.} \bname{plptex(x,y,dx,dy,just,text)}\label{plptex} \addcontentsline{toc}{subsection}{plptex} \descr{Writes text at a specified position and inclination within the viewport. Text is clipped at the viewport boundaries. The reference point of a string lies along a line passing through the string at half the height of a capital letter. The position of the reference point along this line is determined by {\tt just}, the reference point is placed at world coordinates {\tt (x,y)} within the viewport. The inclination of the string is specified in terms of differences of world coordinates making it easy to write text parallel to a line in a graph.} \argu {{\tt x} (PLFLT, input)}{x coordinate of reference point of string.} \argu {{\tt y} (PLFLT, input)}{y coordinate of reference point of string.} \argu {{\tt dx} (PLFLT, input)}{Together with {\tt dy}, this specifies the inclination of the string. The baseline of the string is parallel to a line joining {\tt (x,y)} to {\tt (x+dx,y+dy)}.} \argu {{\tt dy} (PLFLT, input)}{Together with {\tt dx}, this specifies the inclination of the string.} \argu {{\tt just} (PLFLT, input)}{Specifies the position of the string relative to its reference point. If {\tt just=0}, the reference point is at the left and if {\tt just=1}, it is at the right of the string. Other values of {\tt just} give intermediate justifications.} \argu {{\tt text} (char *, input)}{The string to be written out.} \bname{plschr(def,scale)}\label{plschr} \addcontentsline{toc}{subsection}{plschr} \descr {This sets up the size of all subsequent characters drawn. The actual height of a character is the product of the default character size and a scaling factor.} \argu {{\tt def} (PLFLT, input)}{The default height of a character in millimetres, should be set to zero if the default height is to remain unchanged.} \argu {{\tt scale} (PLFLT, input)}{Scale factor to be applied to default to get actual character height.} \bname{plselect(ori,file)}\label{plselect} \addcontentsline{toc}{subsection}{plselect} \descr {This routine can be used to set the graph orientation and to select a file in which the graphics commands should be stored. These options are not supported by all graphics devices (in particular, most interactive screen drivers ignore both the orientation and the filename parameters). The use of this routine is optional. If a device driver needs orientation or filename information, it will prompt the user for it if this routine is not used. This routine, if used, must be called before {\tt plstar} or {\tt pladv}. } \argu {{\tt ori} (PLINT, input)}{The desired orientation. If {\tt ori} is equal to zero then use landscape (x axis is parallel to the longest edge of the page), otherwise use portrait orientation.} \argu {{\tt file} (char *, input)} {The device graphics commands are stored in this file. If this file does not exist, it is created. If it does exist, it is overwritten.} \bname{plsetup(xdpi,ydpi,xwid,ywid)}\label{plsetup} \addcontentsline{toc}{subsection}{plsetup} \descr {PLPLOT needs to know the graphics device resolution so that characters, tick marks, line styles, and fill patterns can be drawn correctly. The page size is required so that the graph can be scaled to fit on the page. The device resolution and page size are hard coded into most of the device drivers. Some devices (or psuedo-devices like an Interchange File Format (IFF) device) allow multiple resolutions and page sizes. This routine can be used to set up things as desired. This routine is optional. If a device driver requires this information and {\tt plsetup} is not used then the user will be prompted for it. This routine, if used, must be called before {\tt plstar} or {\tt pladv}.} \argu {{\tt xdpi} (PLFLT, input)}{The desired resolution in dots per inch in the x axis direction.} \argu {{\tt ydpi} (PLFLT, input)}{The desired resolution in dots per inch in the y axis direction.} \argu {{\tt xwid} (PLINT, input)}{The page width in pixels in the x axis direction.} \argu {{\tt ywid} (PLINT, input)}{The page width in pixels in the y axis direction.} \bname{plsmaj(def,scale)}\label{plsmaj} \addcontentsline{toc}{subsection}{plsmaj} \descr {This sets up the length of the major ticks. The actual length is the product of the default length and a scaling factor as for character height.} \argu {{\tt def} (PLFLT, input)}{The default length of a major tick in millimetres, should be set to zero if the default length is to remain unchanged.} \argu {{\tt scale} (PLFLT, input)}{Scale factor to be applied to default to get actual tick length.} \bname{plsmin(def,scale)}\label{plsmin} \addcontentsline{toc}{subsection}{plsmin} \descr {This sets up the length of the minor ticks and the length of the terminals on error bars. The actual length is the product of the default length and a scaling factor as for character height.} \argu {{\tt def} (PLFLT, input)}{The default length of a minor tick in millimetres, should be set to zero if the default length is to remain unchanged.} \argu {{\tt scale} (PLFLT, input)}{Scale factor to be applied to default to get actual tick length.} \bname{plssym(def,scale)}\label{plssym} \addcontentsline{toc}{subsection}{plssym} \descr {This sets up the size of all subsequent symbols drawn by {\tt plpoin} and {\tt plsym}. The actual height of a symbol is the product of the default symbol size and a scaling factor as for the character height. } \argu {{\tt def} (PLFLT, input)}{The default height of a symbol in millimetres, should be set to zero if the default height is to remain unchanged.} \argu {{\tt scale} (PLFLT, input)}{Scale factor to be applied to default to get actual symbol height.} \bname{plstar(nx,ny)}\label{plstar} \addcontentsline{toc}{subsection}{plstar} \descr{Initializing the plotting package. The program prompts for the device number of the desired output device. The output device is divided into {\tt nx} by {\tt ny} sub-pages, each of which may be used independently. The subroutine {\tt pladv} is used to advance from one subpage to the next.} \argu {{\tt nx} (PLINT, input)}{Number of subpages to divide output page in the horizontal direction.} \argu {{\tt ny} (PLINT, input)}{Number of subpages to divide output page in the vertical direction.} \bname{plstyl(nels,mark,space)}\label{plstyl} \addcontentsline{toc}{subsection}{plstyl} \descr {This sets up the line style for all lines subsequently drawn. A line consists of segments in which the pen is alternately down and up. The lengths of these segments are passed in the arrays {\tt mark} and {\tt space} respectively. The number of mark-space pairs is specified by {\tt nels}. In order to return the line style to the default continuous line, {\tt plstyl} should be called with {\tt nels=0}.(also see {\tt pllsty})} \argu {{\tt nels} (PLINT, input)}{The number of {\tt mark} and {\tt space} elements in a line. Thus a simple broken line can be obtained by setting {\tt nels=1}. A continuous line is specified by setting {\tt nels=0}.} \argu {{\tt mark} (PLINT *, input)} {Pointer to array with the lengths of the segments during which the pen is down, measured in micrometres.} \argu {{\tt space} (PLINT *, input)} {Pointer to array with the lengths of the segments during which the pen is up, measured in micrometres.} \bname{plsvpa(xmin,xmax,ymin,ymax)}\label{plsvpa} \addcontentsline{toc}{subsection}{plsvpa} \descr {Alternate routine to {\tt plvpor} for setting up the viewport. This routine should be used only if the viewport is required to have a definite size in millimetres. The routine {\tt plgspa} is useful for finding out the size of the current subpage. } \argu {{\tt xmin} (PLFLT, input)}{The distance of the left-hand edge of the viewport from the left-hand edge of the subpage in millimetres.} \argu {{\tt xmax} (PLFLT, input)}{The distance of the right-hand edge of the viewport from the left-hand edge of the subpage in millimetres.} \argu {{\tt ymin} (PLFLT, input)}{The distance of the bottom edge of the viewport from the bottom edge of the subpage in millimetres.} \argu {{\tt ymax} (PLFLT, input)}{The distance of the top edge of the viewport from the top edge of the subpage in millimetres.} \bname{plsym(n,x,y,code)}\label{plsym} \addcontentsline{toc}{subsection}{plsym} \descr{Marks out a set of {\tt n} points at positions {\tt (x[i],y[i])}, using the symbol defined by {\tt code}. The code is interpreted as an index in the Hershey font tables.} \argu {{\tt n} (PLINT, input)}{Number of points to be marked.} \argu {{\tt x} (PLFLT *, input)}{Pointer to array with set of x~coordinate values for the points.} \argu {{\tt y} (PLFLT *, input)}{Pointer to array with set of y~coordinate values for the points.} \argu {{\tt code} (PLINT, input)}{Code number for the symbol to be plotted.} \bname{pltext()}\label{pltext} \addcontentsline{toc}{subsection}{pltext} \descr{Sets an interactive device to text mode, used in conjunction with {\tt plgra} to allow graphics and text to be interspersed. This is not currently supported on the Amiga. All the labelling is drawn in vector mode.} \bname{plvpor(xmin,xmax,ymin,ymax)}\label{plvpor} \addcontentsline{toc}{subsection}{plvpor} \descr {Device-independent routine for setting up the viewport. This defines the viewport in terms of normalized subpage coordinates which run from 0.0 to 1.0 (left to right and bottom to top) along each edge of the current subpage. Use the alternate routine {\tt plsvpa} in order to create a viewport of a definite size.} \argu {{\tt xmin} (PLFLT, input)}{The normalized subpage coordinate of the left-hand edge of the viewport.} \argu {{\tt xmax} (PLFLT, input)}{The normalized subpage coordinate of the right-hand edge of the viewport.} \argu {{\tt ymin} (PLFLT, input)}{The normalized subpage coordinate of the bottom edge of the viewport.} \argu {{\tt ymax} (PLFLT, input)}{The normalized subpage coordinate of the top edge of the viewport.} \bname{plvsta()}\label{plvsta} \addcontentsline{toc}{subsection}{plvsta} \descr {Sets up a standard viewport, leaving a left-hand margin of seven character heights, and four character heights around the other three sides.} \bname{plw3s(basex,basey,height,xmin,xmax,ymin,ymax,zmin,zmax,alt,az)}\label{plw3d} \addcontentsline{toc}{subsection}{plw3d} \descr {Sets up a window for a three-dimensional surface plot within the currently defined two-dimensional window. The enclosing box for the surface plot defined by {\tt xmin}, {\tt xmax}, {\tt ymin}, {\tt ymax}, {\tt zmin} and {\tt zmax} in user-coordinate space is mapped into a box of world coordinate size {\tt basex} by {\tt basey} by {\tt height} so that {\tt xmin} maps to {\tt -basex/2}, {\tt xmax} maps to {\tt basex/2}, {\tt ymin} maps to {\tt -basey/2}, {\tt ymax} maps to {\tt basey/2}, {\tt zmin} maps to {\tt 0} and {\tt zmax} maps to {\tt height}. The resulting world-coordinate box is then viewed by an observer at altitude {\tt alt} and azimuth {\tt az}. This routine must be called before {\tt plbox3} or {\tt plot3d}. See Section \ref{threed} on page \pageref{threed} for a more complete description of three-dimensional plotting.} \argu {{\tt basex} (PLFLT, input)}{The x~coordinate size of the world-coordinate box.} \argu {{\tt basey} (PLFLT, input)}{The y~coordinate size of the world-coordinate box.} \argu {{\tt height} (PLFLT, input)}{The z~coordinate size of the world-coordinate box.} \argu {{\tt xmin} (PLFLT, input)}{The minimum user x~coordinate value.} \argu {{\tt xmax} (PLFLT, input)}{The maximum user x~coordinate value.} \argu {{\tt ymin} (PLFLT, input)}{The minimum user y~coordinate value.} \argu {{\tt ymax} (PLFLT, input)}{The maximum user y~coordinate value.} \argu {{\tt zmin} (PLFLT, input)}{The minimum user z~coordinate value.} \argu {{\tt zmax} (PLFLT, input)}{The maximum user z~coordinate value.} \argu {{\tt alt} (PLFLT, input)}{The viewing altitude in degrees above the xy~plane.} \argu {{\tt az} (PLFLT, input)}{The viewing azimuth in degrees. When {\tt az=0}, the observer is looking face onto the zx~plane, and as {\tt az} is increased, the observer moves clockwise around the box when viewed from above the xy~plane.} \bname{plwid(width)}\label{plwid} \addcontentsline{toc}{subsection}{plwid} \descr {Sets the pen width.} \argu {{\tt width} (PLINT, input)}{The desired pen width. The pen width must be between 1 and a device dependent maximum value.} \bname{plwind(xmin,xmax,ymin,ymax)}\label{plwind} \addcontentsline{toc}{subsection}{plwind} \descr {Sets up the world coordinates of the edges of the viewport.} \argu {{\tt xmin} (PLFLT, input)}{The world x~coordinate of the left-hand edge of the viewport.} \argu {{\tt xmax} (PLFLT, input)}{The world x~coordinate of the right-hand edge of the viewport.} \argu {{\tt ymin} (PLFLT, input)}{The world y~coordinate of the bottom edge of the viewport.} \argu {{\tt ymax} (PLFLT, input)}{The world y~coordinate of the top edge of the viewport.}