From: Philippe Verdy (verdy_p@wanadoo.fr)
Date: Tue Feb 06 2007 - 14:10:20 CST
From: <vunzndi@vfemail.net>
> I have tried to do this automatically -- most hinting maintains the
> width of horiziontal amd vertical lines/strokes, slanting curved
> lines tend to become out of proportion, or ugly. It is not easy.
>
> To look nice in Chinese charcters have other rules, such certain
> strokes extend to fill an empty space so there are no large gaps
> inside the character, or contract to avoid touching.
The most probable reason is that you have tried with the default hinting rules.
Actually,each glyph should better be defined with at least two distinct paths, one for the smallest size, one for the largest size (sizes relative to the the Chinese square box), and a linear transformation will move the control points between these two extremes, relatively to the percentage of the square box the traits will use in its relative bounding box.
This requires a specific transform, which comes before the final hinting (where the control points which are first relativey placed within a virtual square box is effectively scaled to the final rendering box), that final hinting will just adjust pixel positions relatively to horizontal and vertical constraints.
Such morphing transform (in the virtual square space) would really improve the rendering at any final rendering point size and independantly of the resolution of the target device.
The same morphing technic could be used to help improving the transformation of alphabetic fonts to other styles (like variable boldening, variable slanting for italic style, or special effects like shadowing or hollowing), and would give better results for fonts that are not provided in multiple styles or blacknesses.
More generally, each control point is described with a natural position, but also with a path function (at least one vector for a linear transform), where the point will move according to a relative normalized index between 0.0 and 1.0 (for minimum relative size and maximum relative size).
The simplest transform (linear) just requires two paths per glyph, which may be simpler to define.
With such models, instead of defining zillions of glyphs, one for each ideograph, we just specify the glyphs for traits, and almost all ideographs are composed much more simply. Then some specific (complex) compositions may have their own specially tuned glyphs not reusing the traits definition. But at least, building a font covering very large subsets of ideographs would become much simpler. The set of default compositions could be standardized as well (but such standard would not prohibit compliant fonts to define specific glyphs for some ideographs where the composition is not easy to adapt without complexing it too much with too many alternate paths for traits).
It would also help browsers, as they would have a database of possible compositions for missing composed characters not defined in the available fonts.
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