Yes, pretty much (I think all) of the sub-pixel rendering ideas predate any of the patents, so they are all moot. (And BTW, this is true for defining fonts as curves (Patrick Baudelaire at PARC did it first, and then Knuth did a lot). Apple did virtually all of the TType work and then shared with MS in a deal, which MS has been abusing. The idea of hinting for small fonts goes back to PARC (and I think was part of the general heuristic of hinting that Butler Lampson formulated for lots of things).
The earliest use of "color picking" as it was known back then was done at MIT in Negroponte's lab in the early 70s. Later and independently Woz came up with an interesting scheme that picked colors to get more resolution on a color CRT. However, no one has done the work to strike down the patents (this is one of the reasons why this broken process today is so pernicious).
Cheers,
Alan
At 04:29 AM 3/30/2006, Andrew Tween wrote:
Sure. There are a number of patents, held/applied for by Microsoft, covering various aspects of sub-pixel rendering of text/images. Here is an example, though a search engine will discover more...
http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=WO0021068&F=0
Some argue that these patents are un-enforcable due to prior art. See http://www.grc.com/ctwho.htm for an overview.
Microsoft indicates that it will license their implementation of sub-pixel antialiasing (a.k.a. ClearType ) for between one and three US Dollars per device. See here for more details...
http://www.microsoft.com/mscorp/ip/tech/cleartype.asp
Apple hold patents for portions of the TrueType hinting mechanisms. The Freetype library source code is distributed in such a manner that it may be compiled with or without the patent restricted code. When compiled without, a patent-free auto-hinting mechanism is employed, which is not as good as the patented code, but far better than nothing. For more information, see...
http://www.freetype.org/patents.html
So, it seems acceptable to distribute patent restricted stuff in source form, and let the user decide what they compile/install/use. The new BitBlt mode does not use any patented code. And so a VM with Freetype plugin/library compiled to use the non-patented auto-hinter, and the modified BitBlt, will be patent free. The sub-pixel stuff, entirely in Smalltalk, and distributed as source, would then be an optional install.
But, of course, I'm not a lawyer :) Cheers, Andy
----- Original Message ----- From: "stéphane ducasse" ducasse@iam.unibe.ch Newsgroups: gmane.comp.lang.smalltalk.squeak.general Sent: Thursday, March 30, 2006 9:11 AM Subject: Re: Henrik antialising
Hi andy
could you explain a bit more the issues with the patents and the license?
Stef On 29 mars 06, at 16:55, Andrew Tween wrote:
I'll see if I can package up a modified Windows VM with Freetype plugin, the new BitBlt mode for sub-pixel, and a semi-stable 3.8Full image. That way, at least the people with Windows can have a play. I think I need to remove the sub-pixel code from the image and make it a changeset, due to the patent issue. I also need to double check that when I built the freetype lib, I didn't compile it with the patented truetype hinting enabled. Patents, don't you just love 'em :)
Does anybody know if it would be ok to put this stuff on ftp.squeak.org ?
Cheers, Andy
----- Original Message ----- From: "Lord ZealoN" lordzealon@gmail.com Newsgroups: gmane.comp.lang.smalltalk.squeak.general Sent: Wednesday, March 29, 2006 3:16 PM Subject: Re: Henrik antialising
I can have this in 3.8?
2006/3/29, Diego Gomez Deck DiegoGomezDeck@consultar.com:
Great!
I can't wait to get a version running on my Squeak.
Cheers,
-- Diego
Here is a screenshot similar to the one Bert posted, but this time with sub-pixel anti-aliasing applied. This will only look o.k. on an LCD monitor with vertical striping in RGB
order.
Cheers, Andy
----- Original Message ----- From: "Diego Gomez Deck" DiegoGomezDeck@consultar.com Newsgroups: gmane.comp.lang.smalltalk.squeak.general Sent: Thursday, March 23, 2006 1:11 PM Subject: Re: Henrik antialising
Hi Andrew,
> I've now got everything installed (in a 3.8 image), and the > Vera fonts
are
> rendering correctly. > It looks very good.
Please send the mandatory screenshot.
Cheers,
-- Diego
--
::Mi blog:: http://blog.lordzealon.com