Re: [Visualpython-users] Creating .png files in Linux

[<fre...@gb...>]

On mardi 15 janvier 2008, Bruce Sherwood wrote:

> The URL you give is not valid.

There is just a missing dot just before 'avi'... Sorry!

> Can you please explain the heart of your program, the function
> generateMovie? I don't understand what is involved in combining many png
> images into a movie. What is the format of the movie? How does one view
> such a movie?
>
> Also, I don't see where/how the povexport facility is invoked (povexport
> is a routine available on the home page of vpython.org). Maybe it's
> buried inside the module "Scene3D" which you don't include?

Ok. The povexport.pov() function is called in the scene.pov() method. It=20
generates the pov file with the given filename of the current scene. But=20
this method is call through __povexport(), which also call povray to=20
generate the png image.

The idea is to define some points where we go in straight line. This is=20
done in the move() method. By points I mean 2 things: the spectrometer=20
position, and the camera position (for zooms). All this is given in the=20
mvt dict. Most of keys are send to sub-objects, and are just angles of=20
differents spectro parts.

At each step in the move(), we call the draw method, which in turn refresh=
=20
all sub-objects and also generate a png image.

There is also a wait() method, which just to generate images at the same=20
position, with respect of the timing.

Last, there is a neutron object which can move along a pre-defined line,=20
and which also call the __povexport() method (through its newFrameSignal()=
=20
object, binded to that method).

At the end, we have all png images. The generateMove() method build a movie=
=20
from that, using mplayer (Don't ask me for all options; a friend gave them=
=20
to me!).

Hope this helps. Feel free to ask for more informations.

=2D-=20
   Fr=E9d=E9ric

   http://www.gbiloba.org