Comments on: Blurred drawing with quartz http://www.dpompa.com/blog/code/blurred-drawing-with-quartz dPompa Blog Sat, 22 May 2010 04:48:49 +0200 http://wordpress.org/?v=2.9.2 hourly 1 By: Ofri Wolfus http://www.dpompa.com/blog/code/blurred-drawing-with-quartz/comment-page-1#comment-5 Ofri Wolfus Thu, 12 Nov 2009 22:10:21 +0000 http://www.dpompa.com/blog/?p=38#comment-5 You're absolutely right. This is just a function I hacked up when I noticed the blurred drawing. I actually discovered about CGRectIntegral() slightly later, and recommend using that. You’re absolutely right. This is just a function I hacked up when I noticed the blurred drawing. I actually discovered about CGRectIntegral() slightly later, and recommend using that.

]]> By: QC http://www.dpompa.com/blog/code/blurred-drawing-with-quartz/comment-page-1#comment-4 QC Thu, 05 Nov 2009 08:47:22 +0000 http://www.dpompa.com/blog/?p=38#comment-4 I am not sure how this is better than CGRectIntegral(). This code could move the right and bottom edges by up to a whole pixel, but it would never move the left or top edges by more than half a pixel. That is a strange bias to have. Finally, there’s a lot of potentially costly type conversion going on: first from double to long double, and then from long to double. Using rint() (and rintf() for 32-bit) would avoid that. Using round() and roundf() would also avoid the dependency on the prevailing rounding mode. I am not sure how this is better than CGRectIntegral().

This code could move the right and bottom edges by up to a whole pixel, but it would never move the left or top edges by more than half a pixel. That is a strange bias to have.

Finally, there’s a lot of potentially costly type conversion going on: first from double to long double, and then from long to double. Using rint() (and rintf() for 32-bit) would avoid that. Using round() and roundf() would also avoid the dependency on the prevailing rounding mode.

]]>