Top Up Prev Next Bottom Contents Index Search

11.5 XGraph, an interface to the xgraph program

The XGraph class provides an interface for the xgraph program for plotting data on an X window system display. The modified xgraph program provided with the Ptolemy distribution should be used, not the contributed version from the X11R5 tape. The constructor for XGraph does not completely initialize the object; initialization is completed by the initialize() method:

void initialize(Block* parent, int noGraphs,
const char* options, const char* title,
const char* saveFile = 0, int ignore = 0);
The parent argument is the name of a Block that is associated with the XGraph object; this Block is used in Error::abortRun messages to report errors. noGraphs specifies the number of data sets that the graph will contain. Each data set is a separate stream and is plotted in a different color (a different line style for B/W displays). options is a series of command line options that will be passed unmodified to the xgraph program. It is subject to expansion by the Unix shell. title is the title for the graph; it can contain special characters (it is not subjected to expansion by the Unix shell). saveFile is the name of a file to save the graph data into, in ASCII form. If it is not given, the data are not saved, and a faster binary format is used. ignore specifies the number of initial points to ignore from each data set.

void setIgnore(int n);
Reset the "ignore" parameter to n.

void addPoint(float y); 
Add a single point to the first data set whose X value is automatically generated (0, 1, 2, 3... on successive calls) and whose Y value is y.

void addPoint(float x,float y);
Add the point (x, y) to the first data set.

void addPoint(int dataSet,float x,float y);
Add the point (x, y) to the data set indicated by dataSet. Data sets start with 1.

void newTrace(int dataSet = 1);
Start a new trace for the nth dataset. This means that there will be no connecting line between the last point plotted and the next point plotted.

void terminate();
This function flushes the data out to disk, closes the files, and invokes the xgraph program. If the destructor is called before terminate, it will close and delete the temporary files.

Top Up Prev Next Bottom Contents Index Search

Copyright © 1990-1997, University of California. All rights reserved.