Normalized Coordinates for Annotations

This function returns normalized coordinates in plot, semilogx, semilogy and loglog plots.

Inspired by http://www.mathworks.com/matlabcentral/fileexchange/10656-data-space-to-figure-units-conversion, which featured coordinate normalization in regular plots, I wrote this quick function to offer the same functionality for logarithmically scaled axes. It can handle two-dimensional x-y plots in which either axis is logarithmic (plot, semilogx, semilogy and loglog plots).