The view is scaled to be as large as possible, without changing the aspect, within the bounds of the window.
On "retina" displays, or other displays where window units != pixels, the view should no longer draw incorrectly.
Screen contents are now displayed using textured quads. This can be updated to expose an FBO once an OpenGL backend for when Pica rendering is being worked on. That FBO's texture can then be applied to the quads.
Previously, FBO blitting was used in order to display screen contents, which did not work on OS X. The new textured quad approach is less of a compatibility risk.