Parameters
Description
This function calculates the x and y range of the plot and returns it in the variables passed. For an image chart, if either the x or y axes are not set up, then the dimensions of the data are used as the axis limits.
In future versions of CPlot, I may extend the functionality of the image chart to have separate plotting and variable axes which would allow for plotting a portion of an image. But for now, I'm not doing that. =)