We need to examine how Prism can better support webnode to improve rendering performance.

Peter Zhelezniakov's reply to the above question:

Webkit sometimes requests us to create an offscreen surface and paint
something on it. So we create an RTTexture. Then I can think of three
things (in fact there may be more) this surface can be used for:

1) The surface may be simply rendered upon another surface. In this case
we can take a shortcut and skip texture-to-image conversion. Though I
believe this rarely happens, if ever.

2) Webkit may request to fill some area using what's painted on the
surface as a pattern. In this case we convert texture to image and
create a pattern from that image. I don't know if a shortcut is possible
here.

3) Finally Webkit may explicitly request bytes to be read from the
surface into a byte array. This is needed to support Canvas'
getImageData() method. In this case we have no choice.