A very detailed post at the Building Windows 8 blog about the graphics subsystem in Windows 8 – very interesting. One part stood out to me, though: “The Metro style design language is typographically rich and a number of Metro style experiences are focused on providing an excellent reading experience. DirectWrite enables great typographic quality, super-fast processing of font data for rendering, and provides industry-leading global text support. We’ve continued to improve text performance in Windows 8 by optimizing our default text rendering in Metro style apps to deliver better performance and efficiency, while maintaining typographic quality and global text support.” All this still doesn’t explain why text rendering on Metro (so not the classic desktop) had to be made as horrible as it is. Please, for the love of god, give us the option of turning ClearType’s subpixel RGB optimisation back on for Metro applications. Fonts look horrible without it, which is kind of ironic given how font-heavy Metro is.
ClearType is gone forever. It’s not needed on ~200DPI displays and worse than useless on Pentile displays. Microsoft clearly thinks these are the future, so is pulling an Apple and forcing people to buy new hardware to get the most out of Windows 8.
Isn’t Pentile essentially doing the same thing as cleartype ( manipulating the subpixels for maximum clarity)?
I’d point out that Windows 8’s metro interface isn’t just for tablets or phones, but actual desktops. I cannot buy a high ~200 DPI display, that I’m aware of.
http://en.wikipedia.org/wiki/List_of_displays_by_pixel_density
There is one listed at 3840×2400, that would work below, but I can’t figure out where to buy it new. Amazon has a couple used for $1600:
http://www.amazon.com/IBM-T221-22-2-3840×2400-Monitor/dp/B00006HS5R
In any case I’m guessing most people don’t have them right now. So Cleartype would help them.
High DPI displays are almost always deployed on tablets. Which is the focus of Windows 8.
Tablets are the focus of windows 8?
This might be exhibit 1A that makes the case that its true, but all communication from microsoft has been that Windows 8 is the desktop and notebook successor to windows 7 meant for keyboard and mouse as well as touch.
Nope. Pentile is a way of organizing subpixels in (eg. RGBG) so there is a 1:1 ratio of pixels to green subpixels but RB pixels are at a lower ratio.
This allows for AMOLED screens to be fabricated more easily and exploits the fact that the eye is most sensitive to green. This arrangement leads to an acceptable display, but not great and fringing can often be seen around text.
ClearType on the other hand is a way of drawing fonts and exploiting the subpixel arrangement of the display (and aligning drawing operation to the pixel grid). AFAIK ClearType only works on RGB type pixel arrangements.
so tl;dr
PenTile is a hardware manufacturing technology designed to save costs. (and in fact tends to reduce clarity when compared to RGB).
ClearType is a software technology designed to maximise clarity, exploiting the subpixel geometry of the display.
Edited 2012-07-24 08:02 UTC
Also, I Windows 8 is meant to support the use case for rotated monitors in landscape/portrait. ClearType isn’t going to work when the sub pixel arrangement is constantly changing.
That’s very true. ClearType is dependent on precise vertical alignment. Rotating the display completely destroys its usefulness.
I’m not sure why rotating the display is an unsurmountable problem. Worst case scenario, you’d just turn it off when its rotated 90 degrees and the text goes from Great to good. Isn’t that better than having it always just good most of the time? It will never be worse than simply having it off all the time, and not any more jarring than switching between a desktop with clear type and back to metro without.
I think the real reason why its not there is that they don’t have time to figure out what to do with it, so they just left it out completely. Watch for it to come back in a service pack, accompanied with ads telling us how they listened to customer feedback to make windows 8 even better.
1) Consistency of the text goes completely out of the window. I imagine that is fairly jarring to the user.
2) The font cache will have to be recreated for ClearType glyphs and non ClearType glyphs. Then the gui will also have to be redrawn with the new glyphs, etc.
Can’t you just maintain two font caches (or four if you want to handle all four common rotations) ?
The entire display is being rotated 90! That is jarring enough to completely obscure any minor font rendering changes.
How may hundreds of kilobytes would it take to have two font caches? Again the screen is being rotated 90 degrees, the entire display will have to be redrawn regardless.
Edited 2012-07-24 13:43 UTC
So one way the fonts look good and the other look less good? What is the point of rotating the display, as people will only ever use it in the better looking orientation?
Minor changes in fonts tend to be easily detected and I’d hypothesize that most people would prefer to get used to a single less good (but consistent) representation as opposed to two differing representations of the same text. It would be an interesting test to try.
In many cases the screen only has to be composited again upon rotation(textures scaled or moved around). But often text will have to be reflowed (in large documents), so it is as you say (redrawn anyway). Two font caches are slightly more inefficient though.
Uhh, because sometimes the content is better viewed in landscape and other times in portrait and the quality of font-rendering doesn’t change that fact?
I bought my 24 inch Dells with 1920×1200 for 450 euro each. Where can I get that 200DPI monitor? I would love to get a 24 inch 3840×2400 version for 450 or even 600 euro.
I realize a lot of people liked it, but I found ClearType really unpleasant. Often got headaches when it was enabled. On machines where I had to work for long periods of time I always turned it off. Can’t say I’m sorry to see it replaced.
That’s a common reaction, and Apple has had similar complaints about its own font-rendering technology in the past for “blurriness” and “fuzziness”. The basic problem that ClearType and related technologies are trying to solve is effectively trying to antialias text rendering on lower resolution displays. As display DPIs start to increase, though, ClearType isn’t really all that useful; because font shapes utilize the higher resolution to approximate curves better without excessive quantization.
Edited 2012-07-24 01:37 UTC
Perhaps this will eliminate attacks on the OS through the use of malicious text strings and fonts. <(^8)<
Edited 2012-07-24 01:32 UTC
Does partial rendering (showed by example of scrolling) mean they are now capable of doing partial screen updates in scene graph based 2d rendering?
The average shape HW feature sound like moving tessellation to hw side but wasn’t that a case for geometry sharers already?
The tail based rendering sound like optimization tailored towards some particular GPU architectures though.
Edited 2012-07-24 06:13 UTC
I always thought that was the entire point of rendering using a scene graph?
Edited 2012-07-24 08:12 UTC
I think scene graph only partially updated internal representation rendering everything every frame (aside from clipped regions).