[Fontconfig] Pango support for `size' OpenType feature?

[Raimund Steger]

Werner LEMBERG wrote:
>>> On the contrary, I think it would be confusing if it depends on the
>>> font name the user selects whether the `size' feature gets applied or
>>> not.
>>
>> The 'LM Roman 12' you're referring to in your fc-list output is just
>> an alternative family name for this particular file and is not
>> technically related to the design size property of that font,
>
> Well, it's the `name' table entry with ID 1, `font family'.  For the
> `size' feature, it should use the `preferred family', ID 16.
>
>> and I think using it in a pattern should only treat it as that and
>> not try to guess some other property values out of it (or substitute
>> it with the Preferred Name, for that matter).
>
> Hmm.  I think it would be good if FontConfig checks ID 16 even if the
> user specifies ID 1.

Ah, I think I see what you mean -- the (cited below) part of the spec 
that says that when a user selects a different size for some 'current' 
font, then the application should scan all other fonts with the same 
preferred family name?

"Size ranges: [...] When any such font is selected by the user, the 
application builds a list of all fonts with this subfamily value and the 
same Preferred Family name, and notes the size range in the current 
font. [...] If the specified size falls in the current font's range, the 
application uses the current font. If not, the application checks the 
other ranges in the subfamily, and if the specified size falls in one of 
them, uses that font. [...]"

I'm not really sure how that applies to fontconfig, given its different 
user interface (family and size are always matched in one go) and the 
fact that it already lists the Preferred Family first, which should 
really suffice in most situations.
In this particular case, "LM Roman 12" is also just a very bad family 
name to return a different size for.


Raimund



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