Datasheet

The Quartz Compositor was designed with modern best practices for graphics in mind. For example, the
drawing coordinate space uses floating-point values, allowing for sub-pixel precision and image smooth-
ing. Compositing operations can take advantage of available hardware, such as the G4’s Altivec vector
unit. Transparency is supported natively and naturally in all drawing operations.
Apple has been able to capitalize on this architecture to provide a number of exciting features, such as
Quartz Extreme and Exposé. Quartz Extreme allows graphic operations to take full advantage of the
graphics processing unit (GPU) found on modern video cards to provide hardware-accelerated drawing.
This has two benefits. The GPU is specially optimized for common drawing operations, so drawing is
much faster than when using the computer’s CPU. Second, by offloading drawing onto the GPU in the
video card, Quartz Extreme frees up the CPU for other tasks. Although in the past developers needed to
use OpenGL to do hardware-accelerated drawing, Quartz Extreme provides this support to Quartz 2D
as well, and ultimately to QuickTime. Exposé allows the user to quickly view all windows at once. It is a
very handy way to find a specific window that might be buried underneath a number of other windows,
as shown in Figure 1-5.
The Quartz Compositor is one of the most innovative features on Mac OS X. Although you will not be
working with it directly in this book, you will feel its influence in almost everything you do.
Figure 1-5
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The Mac OS X Environment
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