Read Me

Read Me — HyperDither 1.3 May 17, 2009 http://www.tinrocket.com/software/hyperdither/ Author: John Balestrieri, Tinrocket, LLC Introduction What does HyperDither do? Short Answer: HyperDither implements the "Atkinson" dithering matrix as an OS X application. Long Answer: HyperDither is an OS X image processing utility that converts color or grayscale images to 1 bit black & white using a sophisticated dithering routine. Specifically, HyperDither implements the “Atkinson” dithering filter. Years ago, during the development of the first Macintosh, Bill Atkinson (of HyperCard, QuickDraw, MacPaint & now nature photography fame) discovered a very elegant dithering filter to convert greyscale image data to the 1 bit black & white Mac video display. The dithering produced by this routine was much higher quality than the now-a-days ubiquitous Floyd-Steinberg or “Error-diffusion” filter (used by QuickTime, PhotoShop). The dither matrix was implemented as an option in Appleʼs long-lost HyperScan software (A HyperCard stack with some XCMDs/XFCNs) that would connect an early Mac to a flatbed scanner. HyperScan, and hence the most-excellent Atkinson dithering routine, has been unavailable for many, many years — but not forgotten! I was able to email Bill Atkinson in January, 2003 and inquire about the details of the algorithm; he was kind enough to respond with a brief write up of the routine — 15 minutes later I had it up and running. Itʼs taken a few spare afternoons since 2003 to pack everything into a nice little application with documentation and an icon — better late than never! *The implementation is not as efficient as the original assembly language code, since it was written in a higher-level language and compiled without optimizations. That said, it should still be plenty fast enough. Pricing The cost of HyperDither is $0.00. (Free to use and own, but not in the public domain) System Requirements HyperDither was developed on OS X 10.4.10 through 10.5.7 — earlier system versions back to OS X 10.3 should work, but have not been tested. HyperDither is a Universal application, which means it will run natively on PowerPC and Intel Macs. Installation Drag the HyperDither application icon to your Applications folder. Usage HyperDither is pretty straight-forward to use. Launch it and drag or paste an image into the main window! If the picture you've pasted in is bigger than the window, the mouse cursor will turn to a hand cursor and let you scroll the image. A few menu options will now be available: File Menu: New Window — Makes a new HyperDither window for you to paste/drag images or a drag folder into. Open — Select an image for processing Batch Process a Folder — Select a folder for batch dithering. Once you select your folder, you will be prompted for the save location. The batch processed images will be placed into a new folder. Save — Saves the current HyperDither image as a PNG file in the location of your choosing. Options m…