Hey Duoas (or whoever else): how do you draw trees?

[Catfish666]

I noticed the Heapsort article of the C++ FAQ, and it has nice animations of trees.
I am interested to know what software was used to create those animations.

http://www.cplusplus.com/faq/sequences/sequencing/sort-algorithms/heapsort/

I ask mainly because I consider writing a big Data Structures article, covering all the good stuff that beginners sometimes post about.

Of course, I still have much studying to do, so even if I decide to write the article, it won't be completed very soon. (The "beginners shouldn't teach beginners" saying comes to mind, yes?)

Edit: grammar.

[giblit]

You could make something like that using GIMP or Photoshop since it looks to be one set image and then each frame has different highlights/text added, just save it as a .gif. Though there might be better software out there for simple 2d animations.

[htirwin]

It looks like a pretty popular question on Google.

http://cstheory.stackexchange.com/questions/1677/what-is-the-recommended-software-for-drawing-data-structures-such-as-graphs-and

http://cs.brown.edu/~rt/gdhandbook/chapters/trees.pdf