I can add those angles easily. But do you know why I did not do it that way?
Because I think what students will get are just two numbers.  Is it really better that way?
I hope we can discuss: Is it better to show those two angles? Especially, you want it to be shown in degree.

The real physics meaning of refraction law is the ratio of those two distances is a constant.
That is why I draw those two lines and show their distance.  And I hope students to find out the relations (for reflection and refraction cases).
And I think this is more important than just showing two numbers.

It is more difficult for student to find relation between those two numbers , especially if there were shown in degree.
Even there were shown in radian, the relation between those two number is n[sub]1[/sub]*sin(c[sub]1[/sub]) =n[sub]2[/sub]*sin(c[sub]2[/sub]).
Can student find more physics meaning with those numbers shown in applet?

I think we should keep the current version:
The ratio of those two distances (horizontal displacement) is a constant. And this is the physics of the refraction law.

n[sub]1[/sub]*sin(c[sub]1[/sub]) =n[sub]2[/sub]*sin(c[sub]2[/sub]) is a mathematics relation.
L[sub]1[/sub] and L[sub]2[/sub] are the distances shown in the applet.
sin(c[sub]1[/sub])=L[sub]1[/sub]/R, and sin(c[sub]2[/sub])=L[sub]2[/sub]/R
So n[sub]1[/sub]*L[sub]1[/sub]=n[sub]2[/sub]*L[sub]2[/sub] is the result of refraction law.
Or  L[sub]1[/sub]/L[sub]2[/sub]=n[sub]2[/sub]/n[sub]1[/sub]  which is a constant.

This is the reason why the applet was designed this way, and  why I draw a circle to help students to find relation between those two distances when light is refracted (Law of refraction) ---  It is also the meaning of sin(c).