Glyphs OriginY meaning

Question

Hello,

I am trying to figure out how to find the precise coordinates of the bounding rectangle of a Glyphs object.
In Silverlight, I am trying to display a rectangle around a Glyphs object. The XAML is from a XPS generated with Microsoft XPS Document Writer

OriginY does not seem to be the top nor bottom of text rectangle.
OriginX however is OK.
If I draw a horizontal line at the OriginY it seems that it's right at the bottom of the letters like 'a','b','c' which is fine but not for a character like 'y'. For character 'y' the line is crossing it in the middle.

There is no RenderTransform specified so that's not the problem.

For instance, I generated a XPS from a Word document with no margins. Looking in the generated XPS i see that OriginY for the Glyphs has a non zero value.

Can anybody give a hint about how that coordinate is generated?


Thanks.

Answer 1

Hi,

It's the location of the Glyph's baseline: http://en.wikipedia.org/wiki/Baseline_(typography)

Section 5.1.1 in the XPS 1.0 spec has a nice picture explaining this.

Regards,

Nick.

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Check out my cross platform xps library and tools at http://nixps.com

Answer 2

Hi nixps,

Thanks alot for your answer.

I suppose finding the bounding box implies parsing the actual font file and use the metrics of the font.

What I mean is thereisn't any way to aproximate it just with the Glyphs attributes, correct?

Thanks.