This code helps to read data points from plots,
first you need to calibrate this tool so that it
can convert pixel information into useful values
from the plots.
It asks you to click on the origin of the plot and
enter the (x,y) value as shown on the plot. Then,
it wants the reference points on the x and y axes,
click on the division points and enter the values.
For the x-axis division, enter the x value only,
for the y-axis division, enter the y value only.
The code assumes the origin y value for the former
and origin x value for the latter. The calibration
is important, so if you are not satisfied with your
points, exit the program. Practise makes perfect,
you can play with it until you feel comfortable.
For the plots :
Open a '.pdf' version of the document, use the
'Image Selection' or 'Snapshot' tool to copy the graph,
using an image editing software such as Photoshop or
Microsoft Imaging, save the plot as a '.jpeg', '.tiff'
or '.bmp'. '.tiff' gives the best results based on the
observations. When the code asks for a filename, enter
the full name including the '.' and the extension,
example : IVplot.jpeg