16-Bit Channels

Color Conversion

Masking

PICT Files

QuarkXPress

QuickTime Movies

QuickTime Still Images

Spatial Transformation: Scaling, Reflection, Rotation

QuickTime Still Images

The biggest news in PhotoJazz 2 is the addition of support for QuickTime™. The all-new PhotoJazz QT takes advantage of new Graphic Import and Export functionality in QuickTime 4 to bring the power of BitJazz perfect-fidelity image compression to dozens of new applications that subscribe to the QuickTime Still Image interface. These QuickTime-savvy applications can automatically open and save PhotoJazz image files without directly supporting the BitJazz interface.

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QuickTime Movies

PhotoJazz isn't just for still images anymore. The QuickTime Compressor and Decompressor components in PhotoJazz QT let you use PhotoJazz for perfect-fidelity archival of QuickTime movies using any of dozens of applications that support QuickTime's Movie interface. In a PhotoJazz movie, the individual frames are in PhotoJazz format, and the movie as a whole is in QuickTime format, so any application that can open or save QuickTime movies can automatically handle PhotoJazz movies.

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PICT Files

For older Macintosh applications that don't yet support the QuickTime Still Image interface directly, PhotoJazz QT lets you package a PhotoJazz image as an ordinary QuickDraw Picture (PICT) file, which can be opened by just about any program on the Macintosh! For simple instructions on how to do this, see the section on PictureViewer.

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QuarkXPress

Another major new feature is the addition of support for QuarkXPress™. The all-new PhotoJazz XT lets you bring your PhotoJazz images right into QuarkXPress and view and manipulate them just like TIFF images.

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Spatial Transformation: Scaling, Reflection, Rotation

PhotoJazz QT will automatically scale, reflect, and rotate an image on the fly as it is displaying its tiles. The scaling feature lets you enlarge or reduce the image to any size, horizontally, vertically, or both, independently. Reflection allows you to flip the image around sideways or upside-down, or both. With the rotation feature, you can turn the image around in quarter circles clockwise or counterclockwise. Reflection and rotation are always perfect-fidelity transformations. PhotoJazz QT performs the scaling with an analytical box filter to minimize degradation while maximizing quality, and only maintains perfect fidelity (and theoretically can only do so) when enlarging by an exact integer multiple. PhotoJazz QT's scaling filter uses a special fast algorithm for seamless tiling of the image. By incorporating these common spatial transformation features in the PhotoJazz QT decompressor, you see the transformed tiles displayed immediately, instead of having to wait for the entire image to get buffered up and transformed. The spatial transformations even work in conjunction with masking and color conversion.

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Masking

If you're zoomed in on part of a PhotoJazz image, or if part of the displayed image is covered up by other windows, controls, or other user-interface elements, PhotoJazz QT will automatically mask off the hidden parts of the image as it is displaying the tiles, no matter how complicated the shape of the obscuring elements. As a result, you see the partially obscured tiles immediately, instead of having to wait for the application or QuickTime to buffer up the entire image and mask off the hidden parts. In fact, since PhotoJazz QT only converts the visible pixels, masking can actually speed it up. Moreover, PhotoJazz now supports selective decompression, so that tiles which are completely hidden won't even be decompressed at all. When viewing small parts of a huge image, this results in a huge speed-up. The masking feature even works in conjunction with spatial transformations and color conversion.

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Color Conversion

On decompression, PhotoJazz QT will automatically convert the image on the fly from the original pixel format in the file to that of the display for most image and display color spaces. For example, you can display a 32-bit RGBA image on a 16-bit color display and still have PhotoJazz QT progressively display the tiles. The color conversion feature even works in conjunction with spatial transformations and masking. Here is a table of the pixel-format conversions built into PhotoJazz QT:

Source	Display
	8-bit Gray 256 grays	16-bit RGB1 thousands of colors	24-bit RGB1 millions of colors	32-bit RGB+Alpha1 millions of colors +
8-bit Gray* 256 grays	•	•	•	•
16-bit Gray+Alpha* 256 grays +	•	•	•	•
16-bit Gray* thousands of grays	•	•	•	•
32-bit Gray+Alpha* thousands of grays +	•	•	•	•
16-bit RGB* thousands of colors		•	•	•
24-bit RGB* millions of colors		•	•	•
32-bit RGB+Alpha* millions of colors +		•	•	•
48-bit RGB* trillions of colors		•	•	•
64-bit RGB+Alpha* trillions of colors +		•	•	•
32-bit CMYK billions of colors		•	•	•
40-bit CMYK+Alpha* billions of colors +		•	•	•
64-bit CMYK* quintillions of colors		•	•	•
80-bit CMYK+Alpha* quintillions of colors +		•	•	•

* With any number of additional channels, which are ignored on display.
¹ Including the Macintosh format and all the most common IBM-PC formats.

Whenever converting from higher precision to lower precision, information is of course lost. To properly view 24-bit RGB images, for example, you need a good 24-bit display system. Likewise, information is lost whenever converting from CMYK to RGB.

For applications which do not support CMYK, PhotoJazz QT uses a quick general-purpose algorithm to convert from CMYK to RGB. Similarly, for applications which do not support multitone, PhotoJazz QT converts duotone and other multitone images to grayscale.

Neither QuickTime nor PhotoJazz QT yet handles L*a*b* images, multichannel images, multiple alpha channels, or spot colors.

PhotoJazz QT supports embedded ICC profiles to permit ICC-enabled applications to take into account the ICC color profiles of the source image and the display to reproduce the image colors accurately.

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16-Bit Channels

PhotoJazz now supports a channel precision of up to 16 bits, so you can use it for high-precision images. Channel depths greater than 8 bits are important for high-end digital photography, medical imaging, and remote sensing imagery. This new feature has been added to the entire suite of BitJazz Tools to take advantage of support for high-precision pixels in both the QuickTime 4 Still Image interface and the Photoshop File Format interface.

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