Quartz (graphics layer)
Quartz specifically refers to a pair of OS X technologies, each part of the Core Graphics framework: Quartz 2D and Quartz Compositor. It includes both a 2D renderer in Core Graphics and the composition engine that sends instructions to the graphics card. Because of this vertical nature, Quartz is often interchanged synonymously with Core Graphics.
In a more general sense, the term Quartz or Quartz technologies can refer to almost every part of the Mac OS X graphics model from the rendering layer down to the compositor. In this use, the term covers Core Image and Core Video as well because the term is applied to a wide range of graphics technologies provided by Apple:
- Quartz 2D
- Quartz Extreme
- Quartz 2D Extreme
- Quartz Compositor
- Quartz Core Framework
- Quartz Display Services
- Quartz Event Services
- Quartz Framework
Quartz 2D & Quartz Compositor 
Quartz 2D is the primary two-dimensional (2D) text and graphics rendering library: It directly supports Aqua by displaying two-dimensional graphics to create the user interface, including on-the-fly rendering and anti-aliasing. Quartz can render text with sub-pixel precision; graphics are limited to more traditional anti-aliasing, which is the default mode of operation but can be turned off. In Mac OS X v10.4, Apple introduced Quartz 2D Extreme, which allows Quartz 2D to use supported GPUs for rendering. In Mac OS X 10.4, Quartz 2D Extreme is not enabled by default, because it may lead to video redraw issues or kernel panics. As of Mac OS X v10.5 Quartz 2D Extreme has been renamed to QuartzGL. However, it still remains disabled by default, as there are some situations where it can degrade performance, or experience visual glitches; it is a per-application setting which can be turned on if the developer wishes.
Quartz Compositor is the compositing engine used by Quartz 2D and other renderers, such as OpenGL, Core Image, and QuickTime. In Mac OS X 10.2 and later, Quartz Compositor uses the processors (GPUs) on supported graphics cards to vastly improve composition performance. This technology is known as Quartz Extreme, and is enabled automatically on systems with supported graphics cards.
Use of PDF 
It is widely stated that Quartz "uses PDF" internally (notably by Apple in Quartz's early developer documentation), often by people making comparisons with the Display PostScript technology used in NeXTSTEP (of which Mac OS X is a descendant) and OPENSTEP. Quartz's internal imaging model correlates well with the PDF object graph, making it easy to output PDF to multiple devices.
See also 
- "Apple - Developer - Graphics & Imaging Overview". Retrieved 2007-02-12.
- "Apple - Developer - Graphics & Imaging Reference". Retrieved 2007-04-17.
- "Apple - Developer - Quartz Programming Guide for QuickDraw Developers: Drawing Destinations". Retrieved 2007-02-12.[dead link]
- "Apple - Info - Docs - About the Mac OS X 10.4.3 Update (Delta)". Retrieved 2007-09-20.
- "Mac OS X DP4 Inside Quartz". Retrieved 2011-09-07.
- Paquette, Mike. "Why Apple didn't use X for the window system". Retrieved 2006-12-23.
- Quartz in Tiger (from a review of Mac OS X 10.4 in Ars Technica)
- Apple's Quartz page for developers
- Introduction to OS X graphics APIs
- Cocoa Graphics with Quartz: Part 1
- Cocoa Graphics with Quartz: Part 2