Testing the software
 --------------------

 With the program there are two testdata files included, test1.png and
 test2.png. Their corresponding data can be found in test1.values and
 test2.values.

 To test the program start it with the command 'g3data test1.png' or with
 'g3data test2.png'. When the program has started click on the button
 labelled 'Set point 1 on X axis' and set out the corresponding point on
 the image by pressing on it. Do the same for point 2 on the X axis, point
 1 on the Y axis and point 2 on the Y axis. The axispoints can also be put
 out by pressing the middle mousebutton for xaxis and the right button for
 y axis. Fill out the entry boxes for the values of the axis points.
 Then continue by putting out the points on the graph itself.

 If you by accident put out an point where it doesn't belong you can
 remove it by pressing the 'Remove last point' button. To remove all
 put out points press the 'Remove all points' button. The axis points
 can be reset by pressing the corresponding button.

 After all the points been put out, press the 'Export point data' button 
 and the coordinates of the data will be printed out through stdout.
 If you'd like to write the data to a file, choose the 'Export data to file' 
 radio button, fill out the filename entry box and press the 'Export point 
 data' button.
 
 Remember to apply the logarithmic scale on x axis for test2.png.