2D Graphics Release Notes for Mac OS X v10.5

This release note describes important changes for applications that use Core Image or Quartz 2D.

Contents:

Core Image Filters Behavior Changes
Performance Implications for Applications Using Garbage Collection

Core Image Filters Behavior Changes

Two Core Image filters—CILinearGradient and CILineScreen—behave differently on Mac OS X v10.5 as compared to Mac OS X v10.4. These changes are implemented in a backwards compatible way. For applications compiled on Mac OS X v10.4, these filters continue to behave on Mac OS X v10.5 as they did previously. However, for applications compiled on Mac OS X v10.5 or later, these filters adopt the new behavior:

• CILinearGradient. On Mac OS X v10.4, the gradient incorrectly renders inputColor0 at inputPoint1 and inputColor1 at inputPoint0. On Mac OS X v10.5, the gradient renders inputColor0 at inputPoint0.

• CILineScreen. The inputSharpness parameter on Mac OS X v10.4 reaches maximal sharpness at 0.0, which is inconsistent with all other halftone filters (CICircularScreen, CIDotScreen, CIHatchedScreen). On Mac OS X v10.5, all halftone filters reach maximal sharpness at 1.0.

Performance Implications for Applications Using Garbage Collection

Garbage collection introduces slight overhead in code execution that is typically not significant for most applications; however, graphically intensive applications may see some performance impact.

There is a known issue with garbage-collected applications using Core Image to process frames from Core Video; the frame memory does not get collected, and the process eventually runs out of address space. If your application processes video frames using Core Image, enabling garbage collection is not recommended.