 to copy out the
current frame buffer contents from the part of memory that's optimized for
writing, and then needs to copy it back in once the previous render target
(layer) is restored.</p>
<p>See also:</p>
<ul>
<li><a href="../../dart-ui/Canvas/save.html">save</a>, which saves the current state, but does not create a new layer
for subsequent commands.</li>
<li><a href="../../dart-ui/BlendMode-class.html">BlendMode</a>, which discusses the use of <a href="../../dart-ui/Paint/blendMode.html">Paint.blendMod