Re: [GM-help] QueryFontMetrics and ascender value.

[Bob F. <bfr...@si...>]

On Fri, 12 Oct 2012, Derek Wueppelmann wrote:

> Is there a preferred method to obtain the actual ascender height of the
> font? I've read about complicated methods by placing the text on a blank
> image and then scanning the image to find out where the place text's top
> is located, but that's a bit expensive to do, if that's the only
> reliable way I suppose I'll go that way, but I hope there is a better
> method. Is this an issue with the fonts that I'm using?

>From my (limited) experience, the only reliable way to place text is 
via the baseline.  The claimed height of the text is really part of 
the font style.  With some fonts the ascender and decender won't ever 
fill the claimed height.  Trying to fit text so the top of rendered 
characters hit a particular point would be difficult.  These are all 
decisions made by the glyph designer.

GraphicsMagick returns the values computed by the FreeType library. 
FreeType library documentation is likely the best place to learn more 
details.

Bob
-- 
Bob Friesenhahn
bfr...@si..., http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/