From: Roland Exler <R DOT Exler AT jk DOT uni-linz DOT ac DOT at>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: data plotting library?
Date: Mon, 16 Sep 1996 08:55:49 -0700
Organization: Institute for el. Measurement, University of Linz, Austria
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Message-ID: <323D7885.5EF2@jk.uni-linz.ac.at>
References: <slrn53b05b DOT mk DOT drosos AT pcdrosos DOT abrdr DOT dreo DOT dnd DOT ca> <51ckuc$a8_001 AT gn5 DOT noord DOT bART DOT nl>
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To: djgpp AT delorie DOT com
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Douglas Eleveld wrote:
> >Is there a data plotting library for simple 2d plots that one can use from
> >within the djgpp code? I am aware of gnuplot, in fact I'm using it now, but
> >I wanted something callable from within my C programs that could give me a
> >quick look at my data. Any pointers/suggestions/advice welcome.

We've written a library for plotting data as a student's-project which runs fine 
and is easy to use. It's written in C++ using GRX2.0 for doing the graphics.

The sources are about 120k, the docs with examples (texinfo) about 85k. The library 
supports plots with more than one graph in a chart, automatic and manual scaling, 
more than one x- and/or y-axis, linear and logarithmic scaling, ...

As this may look a little bit too complicated, take a look at the example below, 
which is Example1 included in the docs.

If anybody is interested in this library, send me personal EMAIL including which 
format (BINHEX or UU-Encoded) you want the ZIP. If someone is interested in more 
details, I could also send the .inf-file (98k uncompressed, ?? zipped).

Hope this helps, 
  Roland

+---------------------------------------+---------------------------+
I Roland Exler                          I EMAIL:                    I
I Universitaet Linz                     I R DOT Exler AT jk DOT uni-linz DOT ac DOT at I
I Institut fuer Elektrische Messtechnik I                           I
I Altenbergerstr. 69                    I Phone:                    I
I A-4040 Linz, AUSTRIA                  I + 43 732 2468 9205        I
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#include "../plot/plot.h"
#include <grx.h>
#include <mousex.h>
#include <math.h>

// just as example
const int maxSize  = 1001;                     // Length of measurementseries
const float timeStep = 13./maxSize;            // scanperiode
float time = 0;                                // timer

// Simulates the reading or calculation of measurements
float readValue() {
  float value;

  value=sin(time/2+timeStep)*sin(time*(10+2*sin(2*time)));
  time+=timeStep;
  return value;
};

int main() {
   float              yDat[maxSize];           // data-array reserved memory

   GrSetMode(GR_default_graphics);
   
   DvLinScale         timeScale(timeStep);
   DvIndexVec         xVec;                    // generate index-vector
   DvScaleData<float> xTimeVec(timeScale,xVec);// generate time-vector
   DvScaleData<float> yVec(yDat,maxSize);      // generate data-vector
   DvXAxis            xAxis("Index");          // generate x-axis
   DvXAxis            xTimeAxis("t / s");      // generate x-time-axis
   DvYAxis            yAxis(0.2,10.1,"I / A");// generate y-axis
   DvNoPoint          noPoint;                 // generate point
   DvGraph            graph(xVec,xAxis,yVec,yAxis,noPoint,"Graph");
   DvPlot             plot("Simple Plot-Demo",0,2,2);
   
   plot.add(graph);             // insert graph in plot
   plot.add(xTimeAxis);         // insert time-axis

   for(int i=0;i<maxSize;i++) { // reading measurements
     yDat[i]=readValue();
     //wait timer
   };

   xTimeAxis.gridOn();          // enable grid
   yAxis.gridOn();
   // set userdefined bounds to time-axis
   xTimeAxis.setNewScale(xTimeVec[0],xTimeVec[yVec.getSize()-1]);
   plot.show();                 // show plot on screen
   getkey();

   GrSetMode(GR_default_text);
  
  return 0;
};