Flash blend mode used for groups is a performance problem and can be avoided generally

What steps will reproduce the problem?
1. Run the lamb animation example from Issue 254, or run the wikipedia zoom
example in
tests/non-licensed/wikipedia/svgzoom/tux.html?svg.render.forceflash=true

What is the expected output? What do you see instead?

The animations run very slow. The pan function is quite herky/jerky.

A significant performance problem has been traced to the BlendMode used by
the group node to implement opacity correctly. This was first used to make
the clouds blend together properly in the SVG Open 2009 logo SVG file. The
clouds are objects in a group and the group needed to implement opacity as
a layer for the objects together. So, setting the group node Sprite to use
BlendMode.LAYER resolved the problem. 

Unfortunately, the BlendMode.LAYER setting appears to cause significant
rendering slowness. Therefore, this mode should only be used when the group
node actually has an opacity setting below 1.0 (which is thankfully a less
common case).

Original issue reported on code.google.com by grick23@gmail.com on 25 Oct 2009 at 10:00

Letractively / svgweb

Flash blend mode used for groups is a performance problem and can be avoided generally #367