How to plot arrow with data coordinates in Matlab?

I know there is a function named annotation can plot arrows or double arrows. But annotation can only plot in normalized unit. For example:

annotation('arrows',[x1 x2],[y1 y2])

Here, [x1, x2] should be a ratio number less than one.

So, my question is how can I plot arrows with a true value rather than a normalized value?

I wonder if there is any other function can approach this or is there any function I can get the axis value of the figure so that I can adjust the true value into a normalized value.

Solution

I've just discovered this method, since I don't want to have to bother with normalised units. Use the latex interpreter:

figure
plot([1:5],[1:5]*3,'.-')
%// Say I want to put an arrow pointing to the location, [3 9]    
text(2.94,8.3,'\uparrow','fontsize',20)
text(2.8,7.8,'point [3,9]')

To make the arrow longer, use a larger fontsize.

Pros

Easier, faster and quicker than using normalised units
Don't need to install any functions (good for us lazy people..)
making use of the LaTeX interpreter, there is a whole range of arrows (up, down, left, right and other angles (see Symbol list)

Cons

Definitely needs trial and error/tweaking to get the correct location of the arrow head relative to the POI.
There is limited control over the length of the arrow
Some latex commands aren't understood by the interpreter (boo).