Kaspar commented on my post Office Adopts New Windows Display Technology “I always wondered why the text in OneNote 2013 looks so much better than Word 2013.” Curious, I typed some math into Word and OneNote on my 3200 x 1800 resolution Samsung ATIV laptop and compared them. The two displays looked pretty similar! For finer examination, I ran the zoomin.exe applet and looked at the pixels of a math italic b in the equation

The character stems in Word were black with varying shades of gray pixels on the edges, while the stems in OneNote had varying hues of colored pixels on the edges as you see here


This post explains why these nonblack pixels are used and why Word 2013 decided to use only gray. While the difference appears minor on my high-resolution display, it’s more noticeable on the common low-resolution 96 dpi displays. Earlier versions of Word looked just like OneNote, i.e., crisp and clear even on 96 dpi displays.

The problem occurs in the first place because raster displays illuminate dots of finite size. If the dots could be way smaller than the characters being displayed, the letters would be sharp. But low resolution displays can look quite dotty. The letters are stored as coefficients of quadratic expressions and are not dotty by nature. To ease the shock of going from continuous curves to dots, a process called rasterization, spatial anti-aliasing was developed. Using gray scale anti-aliasing helped a lot and it’s what Word 2013 uses. Meanwhile back in the 1990’s when LED displays came out with the RGB pixels adjacent to one another in space, a higher-resolution display became possible. This led to ClearType which uses colored pixels for anti-aliasing. ClearType is what OneNote 2013 uses and earlier versions of Word (from Office XP through 2010) used. Note that ClearType only exists on the Windows platform; Apple OS’s and Android don’t have it.

So why did Word 2013 change even on Windows? There is a problem with ClearType: it depends critically on the color of the background pixels. This isn’t a problem if you know a priori that those pixels are white, which is usually the case for text. But the general case involves calculating what the colors should be for an arbitrary background and that takes time. Meanwhile, Word 2013 enjoys cool animations and smooth zooming. Nothing jumps any more. Even the caret (the blinking vertical line at the text insertion point) glides from one position to the next as you type. Jerking movement just isn’t considered cool any more. Well animations and zooms have to be faster than human response times in order to appear smooth. And that rules out ClearType in animated scenarios at least with present generation hardware. And in future scenarios, screens will have sufficiently high resolution that gray-scale anti-aliasing should suffice.

ClearType certainly has been a fabulous thing to have over the years when we’ve been stuck with 96 dpi displays. And I prefer to have it on such displays more than having animations and smooth zooming. But in this day and age of high-resolution smart phones and tablets, animations and smooth zooming are considered to be essential parts of being cool.

FWIW, Kaspar’s criticism came up a few times during the Office 2013 beta, and nearly all of those instances turned out to be from folks who found greyscale anti-aliasing significantly worse than ClearType’s. You can alleviate the problem by running the ClearType tuner, since it can tune the greyscale output as well as ClearType’s colored output. But the best solution is to get a high-resolution display. Have to say I love my touch-screen 3200 x 1800 Samsung ATIV laptop (although I find it hard to select a word by double clicking on it with the touch pad).