animated backgrounds

[Matthias Clasen <mclasen redhat com>]

A while ago Søren Sandmann did some work to support animated
backgrounds. The use case this feature was designed for is to
show pictures of the same scene (e.g. a city skyline) over the
course of the day (say, every 15 minutes), synchronized to the 
current time. 

Unfortunately, we didn't ever get around to take such a photo 
series. But it would be a shame to let this nice feature go 
unused and eventually bitrot away, so I ported it to the new 
appearance capplet last night, and I am sending out this email 
in the hope that maybe some artists will find this interesting 
enough to come up with some cool animated backgrounds. 

Here is how it works:

Instead of a jpeg or png, you create an xml file like the
following:

<background>
  <starttime>1184295694</starttime>
  <static>
    <duration>60.0</duration>
    <file>/path/to/image1</file>
  </static>	
  <transition>
    <duration>30.0</duration>
    <from>/path/to/image1</from>
    <to>/path/to/image2</to>
  </transition>
  <static>
    <duration>60.0</duration>
    <file>/path/to/image2</file>
  </static>
</background>

starttime is the time in seconds since the unix epoch, 
duration is in seconds. 


Matthias