[poppler] Exposing hinting setting

[James Cloos]

>>>>> "Albert" == Albert Astals Cid <aacid at kde.org> writes:

Albert> So, should we expose hinting setting through a GlobalParams
Albert> setting that can be set from "userspace" via the glib/qt
Albert> bindings? So that users that like hinting can set it to on?

Thinking about this, there are two radically different use cases for a
document viewer.  Reading the document or confirming how it will look
once printed.

In the latter case significant hinting — such as what ttf instructions
generate¹ — is unwanted.  The glyph placement needs to match what will
come out of the printer.

OTOH, legibility is of course king when reading the document on screen.

Freetype's “light” autohinting (which leaves the horizontal metrics and
placement alone and only distorts the glyphs vertically²) is OK for both
cases, but the other hinting options — autofit, postscript or the ttf
bytecode interpreter — generally only make sense in the latter case.

So, making the option available is useful.  The default should be to use
light autofit in all (freetype) cases — including cairo.  If you prefer
to avoid added complexity leave it at that.  Otherwise add the option to
choose whichever hiting style the user prefers for their given usage.

-JimC

1] The bytecode interpreter must still, of course, be used for those
   few, known CJK fonts which cannot render w/o it; ie those supported
   by the unpatented bytecode option when configuring freetype.)

2] Whether the light module does horizontal-only distortion for
   vertically set scripts is an interesting question.

-- 
James Cloos <cloos at jhcloos.com>         OpenPGP: 1024D/ED7DAEA6