Tiger Field Guide

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Web & communication software

Adding to the Core

If you think back to the release of Panther—Apple’s last major, cat-themed OS X update from October 2003—you might recall the arrival of Core Audio and Core MIDI. These two technologies introduced low-level architectural changes which sound applications, such as Logic, could exploit.

Apple pulls off the same trick in Tiger, only this time with graphics. OS X 10.4 adds Core Image technology, which gives developers easier access to pixel level effects than they had in previous versions of OS X while offering a new way to create such effects.

Core Image lets applications enjoy the power of the speedy, programmable graphics processing units, or GPUs, in today’s video cards from ATI and Nvidia. Core Image is powered by floating-point calculations, which produce highly-accurate color on an individual pixel basis. That, in turn, helps achieve great quality and color range that’s scalable to your system.

Prior to Core Image, Mac developers needed to know a lot about pixel-level programming to benefit from fast image processing without rendering delays. But now, it’s much easier and quicker to create effects and transitions because Core Image handles most of the work. (If your video card doesn’t have a programmable GPU, Core Image makes more efficient use of your CPU by adjusting for Velocity Engine and dual-processors.)

Core Image uses Image Units, its plug-in architecture for accessing filters, transitions, and effects. There are about 100 Image Units included with Tiger, including blurs, color blends, sharpeners, gradients, tilers, transitions, halftones, and distortions. Developers can tap into these includes filters without having to write their own, or create new ones that will work across applications.

Although Apple’s Core technologies (Core Audio, Core Data, Core Image, and Core Video) exist to help people develop applications for OS X that tap into the operating system’s under-the-hood work, you’ll ultimately benefit from them as well. Core Image creates a new standard for graphics plug-ins that many of your apps will be able to enjoy, and makes better use of the fast new graphics cards included in Macs, leading to more responsiveness applying filters and effects.

Currently, Core Image is supported on the ATI Mobility Radeon 9700, and Radeon 9600 XT, 9800 XT, and X800 XT models, as well as on Nvidia’s GeForce FX Go 5200, GeForce FX 5200 Ultra, and GeForce 6800 Ultra DDL and 6800 GT DDL cards. Look for Core Image-support to appear in other cards with programmable GPUs in the future.

[ Jonathan Seff is the Senior News Editor at Macworld . ]

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