Font rendering (was Re: [squeak-dev] Re: Statistics on merging Cuis with 3.10 on Morph hierarchy)

Colin Putney cputney at wiresong.ca
Tue Apr 28 02:47:52 UTC 2009


K. K. Subramaniam wrote:
> On Monday 20 April 2009 9:17:38 pm Bert Freudenberg wrote:
>> Linux and Windows users are accustomed to heavily hinted font
>> rendering, looking overly "crisp" because lines are snapped to the
>> screen pixel grid. The result has little resemblance to the true
>> character shape as it would appear when printed on paper, but it's
>> what they are used to. In contrast, Apple's and Adobe's font rendering
>> is much more truthful to the paper appearance, but looks "blurry" to
>> Windows and Linux users
> Squeak's screen and its contents are meant to be consumed on bitmap monitors
> and rarely printed on paper, so why should the fonts be optimized for paper
> rendering and not display monitors?
>
> Confused .. Subbu

Hi Subbu,

It isn't a question of optimization for a particular medium. Printers 
can render fonts at high resolution, so the quality of the rendering is 
quite good: crisp edges, smooth curves and high fidelity to the letter 
shapes defined by the font. Screens are much lower resolution, and 
especially at smaller point sizes, it's impossible to match the 
rendering quality of a printer.

So how do we get a good image at low resolution? Apple's strategy is to 
alter the *intensity* of certain pixels in the rendered image to 
preserve fidelity to the letter shapes and provide the illusion of 
smooth curves. Microsoft's strategy is to alter the *position* of 
certain pixels in the rendered image to preserve the crisp edges that 
one finds in printed text.

Apple emphasizes fidelity to the font's character shapes, resulting in 
bluriness, while Microsoft emphasizes clarity, resulting in distortion. 
Either is a reasonable choice.

Colin



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