Sharp characters step up e-book campaign

October 1, 1999

Microsoft and Adobe are battling to establish a

readable alternative to the printed book. Tony

Durham reports Microsoft has revived interest in e-books - book-sized machines for reading electronic literature - by unveiling a program intended to make reading from screens easier and more enjoyable.

Microsoft Reader has tools for bookmarking, highlighting and annotation, a built-in dictionary, and a system to prevent illegal copying. It also incorporates Microsoft's ClearType technology, which is claimed to improve readability on colour screens.

ClearType uses individual dots of colour to define letterforms at three times the screen's nominal resolution. But there have been arguments over the originality of Microsoft's technology. Computer technologist Steve Gibson claims that the designers of the Apple II computer used a similar idea more than 20 years ago.

The colour LCD screens used on most laptop computers consist of hundreds of thousands of square picture elements or pixels. Each pixel is subdivided into three tiny vertical strips, which emit the colours red, green and blue. Normally it is assumed that the eye will blend the colours, and the fact that each colour comes from a slightly different place on the screen is ignored. But ClearType turns this fact to advantage.

The idea is that an edge between light and darkness can be positioned precisely on the screen by controlling individual colour dots rather than whole pixels. This method, known as sub-pixel rendering, effectively multiplies the screen's resolution by three, at least in the horizontal direction.

There is no improvement in vertical resolution, but horizontal precision is precisely what is needed for displaying text and typography.

It means that the thickness of vertical strokes can be very precisely controlled, while the slanting strokes of italics and letters like A, V and X appear less jagged.

When Bill Gates demonstrated the ClearType technology in Las Vegas last November, Microsoft's chief technology officer Nathan Myhrvold said: "We have overcome a major obstacle to ubiquitous on-screen reading - bad readability."

But Mr Gibson, a graphics technologist and light-pen designer in Laguna Hills, California, felt Microsoft should have given more credit to the Apple II designers who used sub-pixel rendering technology 22 years ago on the first mass-produced personal computer.

His evidence is posted on a website along with examples of sub-pixel rendering that can be viewed on an average laptop with a standard web browser.

Mr Gibson says he is gathering evidence that IBM, Xerox and Honeywell worked on similar ideas.

Microsoft may still have grounds for claiming that ClearType is a breakthrough, since sub-pixel resolution is not its only trick for improving the appearance of fonts. ClearType also uses anti-aliasing, a blurring technique that makes shapes appear less blocky and jagged.

Anti-aliasing is nothing new and explanations of the technique have been in computer graphics textbooks for years. The Acorn Archimedes computer boasted anti-aliased fonts as early as 1987.

Where Microsoft appears to have done some truly original work is in using just the right amount and type of anti-aliasing to smooth away the coloured fringes that are the natural result of sub-pixel rendering. Because the eye tends to average colours over an area, a red fringe could be corrected by tinting nearby pixels with the complementary colour blue-green or cyan.

The e-book market is in the throes of a standards battle. Microsoft's Open Ebook initiative is supported by Librius, Nuvo-Media, Softbook and, with reservations, Everybook.

Everybook strongly supports Adobe's PDF format, recently enhanced with copy protection and payment features. Glassbook supports both standards. PDF documents usually print well, even when they are hard to read on screen. So Adobe could still win the battle if consumers resist all efforts to make them read from screens and instead choose to have books printed on demand. ClearType:


Steve Gibson:


Others: www.(company).com

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