openlayers/openlayers — pull request #796 by iacovlev-pavel (2012-12-12 13:37:04+00:00)
Title: Canvas graphic rotation support and canvas graphic redraw optimizations 

#1
Added canvas graphic rotation support (style.rotation), at the moment works only with SVG (did not test VML).

#2
With the current implementation every time a graphic is drawn a new image is created, then the onload handler is attached and the render process is executed in this handler's success result.
This has some performance implication (flickering) - if many features have the same graphic (typical in maps), or when the graphic is redrawn often with a rotation, offset, position etc. I added a quick fix which caches the last image, it did get rid of flicking in all of my use cases.