IE9 vs FF4
I get completely identical results
either way. When using GDI FF4 and IE9 are equal. When using D2d/DirectWrite FF4 and IE9 are equal.
IE9 has an advantage in that you can change on the fly without a restart. Many pages render in IE7 compatibility mode by default giving the impression it works better, it doesn't, the page has just dropped down to GDI rendering, so it isn't using DirectWrite. On using About:config gfx.direct2d.disabled.
I have read that this is exactly the same as unchecking "Use hardware acceleration when available". Both of them disable D2d and leave D3d alone. Also changing it in the in advanced preferences over-rides the about
:config setting , so you may as well set it in the advanced preferences and forget the about
:config setting, unless you have a test that verifies it does something different.
Bug or Feature?
Do a bit of research and you will find that the softer smoother (blurrier) fonts are on purpose and a sign it is working as intended
. In fact if driver
differences are playing a part at this point, it is most likely the systems that show sharp fonts that have broken drivers
because they are reverting to GDI fonts. These new fonts are more typographically correct
. DirectWrite fonts are meant to ignore pixel boundaries to flow more naturally and have bidirectional Anti-Aliasing. This makes for a more accurate font representation, that flows, moves and transforms better. BUT
it also means that GDI fonts that snap to the grid will be sharper. The difference is negligible on larger B&W fonts, but smaller fonts,reverse fonts(light on dark) and color fonts can look quite bad in DirectWrite
Unfortunately the internet is full of small, color, reverse fonts. So until Microsoft finds a work around to improve small/color font output many of use will have to work around this by disabling Hardware Acceleration in FF4 or using an IE compatibility mode. Demonstration of DirectWrite Text "Benefit".
Find a page with reflowable text, not all of them work, but this one does so you spot it the first time: DirectWrite « Marc Gregoire’s Blog
Now start shrinking the page down horizontally to squish the text, very slowly. DirectWrite on
: Shrinking is very smooth and even until a word gets moved. DirectWrite off
: Shrinking jitters all over the place as words shake back and forth.
Again both IE9/FF4 behave the same way. IE9 is easier to test because you can switch without restart, but they are both the same.
Part of the point of DirectWrite is that it ignores pixel boundaries so movement, transformations are very smooth(but can have softer text). GDI text respects these boundaries so it has to jump to the grid (but can have sharper text). Anti-Aliasing Tuner extension for FF4.
I did some testing with this and while I could get the sharpness improved, the letter spacing became even worse
! Look at the tuner section one word at a time. The letter spacing is a mess. Look at "Bioware", it is there twice, each spaced a different way, look at the mess in "representatives"... This "fix" is not really usable IMO.
Actually if you read the text for the extension it says: Known Issue:
* Glyph position is not correct when GDI* rendering is selected. (no idea to fix...)
Not correct is one way to put it. Random and drunkenly spaced is another. Cleartype Off, Hardware Acceleration works! If you don't like cleartype at all, you are in luck
. When I turn off cleartype (unclick the "Turn on cleartype" box in cleartype tuner) it respects this and Disables DirectWrite fonts, but maintains Direct2D graphics acceleration.
But this only works in Firefox. IE9 Does not let disable Cleartype. Fonts have no AA at all
and when I do the jitter test I describe above, they jitter like GDI fonts. So from any measure these appear to be GDI fonts without AA/CT or anything. They look just like CT-OFF without HW acceleration. No difference.
Direct2d Graphics demos are still accelerated.
Go to any of the Direct2D demos like this one and they are still full speed accelerated: HTML5 Speed Reading Output sample:
Compare this output with the above. If you look closely you can tell this has not CT, NO AA. It is even sharper than GDI sample above. Letters are also spaced correctly. Bottom line
We either have to workaround and disable it, or get used to it. If you don't like Cleartype you are in luck. It appears you get the best of both worlds. HW acceleration without DirectWrite fonts.
For the rest of us, hopefully Microsoft will find a way to improve small color font CT rendering so it looks like the GDI fonts we like, before this starts getting forced on us everywhere, as this is Microsofts new text system going forward.