iOS: Watch out for shadows
Quick tip … when working with CALayer shadows, its useful to set shouldRasterize to YES - this helps with performance (along with setting the shadowPath). The problem is that it also rasterises everything else in the layer, including all the text - which then looks awful. There are a couple of options …
set the rasterization scale (thus ensuring the rasterization is done at correct scale for the device - retina/non-retina):
layer.rasterizationScale = [[UIScreen mainScreen] scale]];
or move the shadow into its own layer and adding that as a sublayer.
Both options work - it depends on what your specific use case is, as to which is going to be better for your app.