Khan/khan-exercises — pull request #8913 by stchangg (2011-12-18 10:47:23+00:00)
Title: Interactive telling time

What it is: New exercise, an interactive version of "Telling time"

Corresponding Trello bug: "Telling time, interactive" in "Queued up"

#### telling_time_interactive.html
* "Set the clock to 3:45". User moves clock hands accordingly.
* Probably has whitespace issues, sorry.
* Hints might be overkill/unclear... I tried. =/

#### time.js
* Copied and extended analogClock from graphie-helpers.js to an addAnalogClock() function inside time.js
* NOTE: several functions (coordToDegrees, degreesToCoord) may belong in other packages. Any ideas where?
* NOTE: roundToNearest() belongs in math.js

#### interactive.js
* Added a snapPoints option to constraints.fixedDistance to allow snapping around a circle (fixedDistance says the point can move in a circle). snapPoints is the number of points that can be snapped to around the circle.
* NOTE: to implement this functionality, there is a bit of redundancy with functions in angles.js and time.js, but this might be unavoidable since interactive.js may be used without the others.

#### telling_time.html & telling_time_0.5.html
* No change currently
* NOTE: should be updated using new time.js package (if accepted)

#### angle.js
* Added toDegrees() function

#### math.js
* No change currently
* NOTE: I tried to add roundToNearest (currently in time.js) to math.js but for some reason I couldn't get it to work. Something about how math.js is compiled? Is it a special file compared to the others?

#### graphie-helpers.js
* No intentional change
* NOTE: if time.js is accepted and telling_time.html & telling_time_0.5.html are updated, we should remove the analogClock() function from here.