[cairo] LCD filtering in cairo, use default filter?

[Sylvain Pasche]

James Cloos wrote:
> Ideally, the default should be the light hinting with the light filter.
> 
> Except, if the bytecode interpreter is available, certain well
> instructed glyf fonts should get ‘full’ hinting and the legacy
> filter.

How do you justify these choices? Personal preferences or technical reasons?

Of course if we can see there is a strong need for people to be able to 
choose between the available filters, that goes if favor of the 
configuration option.

> One thorny issue, though, is the case of document viewers  (such as
> evince, xpdf, xdvi, et al).  When the goal it to read a document on
> screen, the above continues to hold.  But when the goal is to check
> (a simulation of) the document’s as-printed appearance, light auto-
> hinting and filtering should be used exclusively.
> The other thorny issue is treating the UI elements differently than
> the document text.  In the simulated printout case, even if the doc
> uses the same font as the UI, the UI should get the ‘full’ hints if
> available and the document light auto.

I would rather expect that the print preview is not using subpixel 
antialiasing, but gray antialiasing instead. This means that the type of 
lcd filter will have no impact in that particular use case.

Sylvain