Thanks, Mr. Kantor.
I did use Cartesian as the example. But I still not clear about some part of
your code. We decided to build our own using openGL to draw graphs, and fltk to
draw x and y axises.
I tried couple things, but nothing seems to work. Here is the simpler version
of my code.
#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/fl_draw.H>
#include <FL/Fl_Double_Window.H>
#include <FL/Fl_Box.H>
#include <FL/Fl_Button.H>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
class Axis;
class X_Axis;
static const int MAX_LABEL_FORMAT = 16;
static const int MAX_LABEL_LENGTH = 32;
enum Ca_Damage {CA_DAMAGE_ALL=1, CA_DAMAGE_ADD=2};
X_Axis *xAxis;
////////////////////////////////////////////////////////////////////////
class Axis: public Fl_Box
{
protected:
double min;
double max;
int minPosition;
int maxPosition;
int tickLength;
virtual int MinPosition()=0;
virtual int MaxPosition()=0;
public:
Axis(int x,int y,int w,int h,const char *l=0): Fl_Box(x,y,w,h,l)
{ tickLength = 5; }
double Minimum() const { return min; }
double Maximum() const { return max; }
void Minimum(double minimum) { min = minimum; }
void Maximum(double maximum) { max = maximum; }
void Axis::FindScientificValue(double val, int *mantisa, int *exponent)
{
for (*mantisa=(int)val, *exponent=0; *mantisa > 1; *mantisa =
*mantisa/10, *exponent += 1)
{
if (*mantisa < 10)
break;
}
}
};
////////////////////////////////////////////////////////////////////////
class X_Axis: public Axis
{
protected:
public:
int MinPosition() { return minPosition; }
int MaxPosition() { return maxPosition; }
void draw();
public:
X_Axis(int x, int y, int w, int h, const char * label=0) : Axis(x, y, w, h,
label)
{
minPosition = x;
maxPosition = x + w;
}
~X_Axis() {};
};
////////////////////////////////////////////////////////////////////////
void X_Axis::draw()
{
int i, mantisa, exponent, x0, x1, y0, y1, width1, height1, width2, height2,
j=-2, loop;
char labelFormat[MAX_LABEL_FORMAT];
char label1[MAX_LABEL_LENGTH];
char label2[MAX_LABEL_LENGTH];
float tickValue;
//Set line color and style, font for label
fl_color(0,0,0);
fl_line_style(FL_SOLID);
fl_font(0, 8);
//position of y0 and y1
y0 = y() + 1;
y1 = y() + 1 + tickLength;
j = -2; //tick starts from 0.01, 0.1, 1, 10, 100, ....
//tick at every 10^i with 0.01 <= i <= 10^exponent. max is in log value.
max = mantisa*10^exponent
FindScientificValue(pow(10,max), &mantisa, &exponent);
if (mantisa == 1)
tickValue = (float)1 / (exponent + 2) * w();
else
tickValue = 1 / ((float)mantisa / 10 + exponent + 2) * w();
for (i=0; i <= exponent+2; i++)
{
x0 = minPosition + (int)(tickValue * i);
x1 =
minPosition + (int)(tickValue * i);
fl_line(x0, y0, x1, y1);
//draw tick
if (i < 2)
//format label
0.01 and 0.1
sprintf(labelFormat,"%.2f",pow(10,j));
else
sprintf(labelFormat,"%.0f",pow(10,j));
//format label 1, 10, 100, etc.
sprintf(label1, labelFormat,pow(10,j));
fl_measure(label1, width1, height1);
//draw label at each tick
if (i == 0)
//display label
at first tick
fl_draw(label1, x0, y1 + tickLength + (height1 / 2));
else if (i == exponent+2)
//display the end of the label
at the tick
fl_draw(label1, x0-width1, y1 + tickLength + (height1 /
2));
else
//display
middle length of the label at the tick
fl_draw(label1, x0 - (width1 / 2), y1 + tickLength +
(height1 / 2));
j++;
}
}
///////////////////////////////////////////////////////////////////////////
void start_cb( Fl_Widget* o, void*)
{
xAxis->Maximum(log10(1000));
xAxis->Minimum(0.1);
xAxis->redraw();
}
///////////////////////////////////////////////////////////////////////////
int main(int argc, char **argv)
{
Fl_Double_Window window(1000,750, "Drawing Graphs");
window.begin();
xAxis = new X_Axis(643, 217, 348, 20,"");
xAxis->Maximum(log10(600));
xAxis->Minimum(0.01);
Fl_Button* start = new Fl_Button(12,370+320+5, 60, 25, "&Start");
start->callback( (Fl_Callback*) start_cb );
start->labelsize(13);
window.end();
window.show(argc, argv);
return Fl::run();
}
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