Kenneth Whistler writes: > Patent #1: US5155805: Method and apparatus for moving control points > in displaying digital typeface on raster output devices. May 8, 1989. > > Patent #2: US5159668: Method and apparatus for manipulating outlines > in improving digital typeface on raster output devices. May 8, 1989. > > Patent #3: US5325479: Method and apparatus for moving control points > in displaying digital typeface on raster output devices. May 28, 1992. > > "It's important to understand that the patents do not prevent > anyone from reading, converting or generating TrueType fonts. > As they only concern the subtle art of hinting TrueType glyphs, > it's even possible to legally display text with TrueType fonts, > as long as the patented techniques aren't used to optimise the > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > bitmaps at small pixel sizes." > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > The abstract for US5155805 starts out: "A method for manipulating > the control points of a symbol image represented by an outline > font to improve the appearance of the font on raster output devices > ^^^^^^^^^^^^^^^^^^^^^^^^ > which are under control of a computer." > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > There, is that clear enough for you?
It seems clear to me that this looks like a call by Apple to font authors to offer high quality fonts to their clients, but clients cannot use them to render text with these hinted fonts without getting a licence for the renderer they need. As FreeType does not offer to its users such a license, it cannot implement hinting mechanisms in its renderer. So FreeType cannot use fonts hinted with Apple technology. This means that font authors cannot seriously sell hinted font designs to FreeType users, and these fonts will only work in compliant environment that include such a license such as Windows, MacOSX, and possibly other vendor-supported environemnts. May be it's possible in Linux with a commercial distribution like RedHat, if RedHat pays its license distribution rights to Apple, but then FreeType would need to be modified to include that licensed material and this may expose it to license problems if FreeType uses the GPL which requires contributing the modified source code to anyone asking them. That's what is known as the "viral" nature of the GPL. If FreeType uses the GPL, it will have to include a generic extension mechanism to support a commercial extension of a compliant hinting renderer, so that commercial vendors like RedHat can provide the needed licensed renderer within their distribution. Another way would be to develop another hinting system that does not include something claimed in the above patents. It will be hard even if the technics and formats used are completely different, because the terms of the patent are quite vague and seem to cover nearly all the aspects of font hinting, which is exactly a way to move control points that define glyphs. The only alternative seems to be hinting fonts with something else than moving control points; for example by embedding bitmaps of glyphs at small sizes, so that no control points are involved in this operation, or by providing alternate sets of glyphs, but this breaks the continuity of the font at any intermediate size, even if antiscaling is used to limit this effect. If the patent was only in the supported table formats and instructions defined in Apple's specification, then other formats could be used and provided within font designs and used within compliant renderers that only use these alternate hinting tables. But will typographers accept to develop these alternate font tables when more than 99% of their market uses a Microsoft of Apple OS or a propriatary Unix system, or a commercial Linux distribution? __________________________________________________________________ << ella for Spam Control >> has removed Spam messages and set aside Newsletters for me You can use it too - and it's FREE! http://www.ellaforspam.com
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