Question

I have a UILabel on which I perform a CGAffineTransformConcat to tilt the text for some degrees. Instruments CA analysis tells me that the view has misaligned pixels now (leave out the transformation and the label is fine).

I wonder if there is any way to get rid of the misaligned pixels in this label or if that would be not possible since the transformation causes fractional values in the coordinates anyway.

I did a CGRectIntegral call on the frame which has fractional values but for some reason the view is still misaligned.

Answer 1

When a layer is rotated by an angle that is not a multiple of 90° it cannot be pixel-aligned.

If you want to present tilted text and nevertheless need aligned pixels the only way is to draw the layer (view) yourself. You would align the layer and instead do the rotation using Quartz.

Note after edit: You cannot use the frame when a transform is set:

Warning If the transform property is not the identity transform, the
value of this property is undefined and therefore should be ignored.