Re: [ft] face->ascender always has the same height

[Nikolay Sivov]

On 28.11.2016 16:09, Olumide wrote:
> Dear List,
> 
> I've written a bit of code to rasterizing fonts at any arbitrary size as
> follows:
> 
> #define FONT_HEIGHT 18
> 
> FT_Size_RequestRec req = { FT_SIZE_REQUEST_TYPE_BBOX , 0 , FONT_HEIGHT *
> 64 , 0 , 0 };
> CHECK_STATUS( error , "Request size rec" )
> 
> FT_Request_Size( face , &req );
> CHECK_STATUS( error , "Request size" )
> 
> Oddly, face->ascender always has the same height. Why is this the case?

Because it's not scaled. It's a font global design metric that for SFNT
fonts unfortunately exists in 3 different places: hhea table, and two
times in OS/2 table of appropriate version. Freetype tries to return
reasonable value from all three of those.

> I need the ascender in order to locate my rasterized font in the
> requested box (of max size FONT_HEIGHT).

Note that rendered bitmap does not necessary fit into a box of
FONT_HEIGHT height. Ascender/descender fields are used for layout
estimation and scaling on Windows.

> 
> Regards,
> 
> - Olumide
> 
> 
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