iPhone UIView Has Blurred Subview | markjnet
As the box is sized with an even number of pixels, 174 x 82, setting the origin relative to the center results in an origin at half pixels: 73.5, 69.5. Core Graphics goes ahead and renders at the half pixel position, but as the view is drawn at 100% it means every pixel in the view lies at half pixels on the screen, so each pixel is smeared between 4 neighboring pixels resulting in a big blur.
Interesting side-effect.