Re: Cut-outs

Hi Erik,

We use the glyph bounding box because it is typically simple to get hold 
of in whatever API you might be using to gather information about the 
glyph. Not all APIs seem to provide more detailed access to glyph metrics, 
whereas the bounding box appears to be pretty universally available.

Daniel



From:   Erik Ronström <erik@ompom.se>
To:     Daniel Spreadbury <D.Spreadbury@steinberg.de>
Cc:     public-music-notation-contrib@w3.org
Date:   09/04/2018 00:47
Subject:        Re: Cut-outs



Hi Daniel,

Thanks for the clarification!

Just out of curiosity: what was the rationale for choosing the bottom-left 
corner as reference rather than the origin point?

Erik



> 9 apr. 2018 kl. 01:22 skrev Daniel Spreadbury 
<D.Spreadbury@steinberg.de>:
> 
> Hi Erik,
> 
> Thanks for your email. I can confirm that the cut-outs are indeed 
relative to the bottom left-corner of the bounding box, and not the origin 
point. I will raise an issue in the GitHub repository to clarify this in 
the specification.
> 
> That means that there is indeed a bug in the way the web site renders 
the cut-out points, which we'll take care of.
> 
> Daniel
> 
> 
> 
> From:        Erik Ronström <erik@ompom.se>
> To:        public-music-notation-contrib@w3.org
> Date:        07/04/2018 22:12
> Subject:        Cut-outs
> 
> 
> 
> Dear smuflers,
> 
> Regarding cut-outs, the SMuFL spec says:
> 
> > Each cut-out is specified as a pair of X,Y coordinates (in spaces), 
describing the innermost corner of a nominal rectangle that intersects the 
bounding box. For example, cutOutNE specifies the bottom left corner of a 
rectangle that intersects the top right corner of the bounding box of the 
glyph. The positions of each of the other corners of the cut-out rectangle 
are calculated using the bounding box of the glyph.
> 
> However, it doesn’t explicitly state the origin of the coordinate 
system. IMO, it would make most sense to use the same origin as the 
glyph’s origin. But using the metadata for Bravura 1.204, this gives wrong 
results. It looks like the cut-outs in Bravura are instead measured from 
the bottom-left corner of of the glyph’s bounding box.
> 
> The glyph images at e.g. 
http://www.smufl.org/version/latest/glyph/accidentalNatural/confirms that 
something fishy is going on. My interpretation is that they use Bravura’s 
metadata to draw the cut-out points, but draw them according to the 
glyph’s origin, which makes them end up far too high.
> 
> So is this a bug in the Bravura metadata, or is it the website that uses 
the metadata incorrectly?
> 
> Best regards
> Erik Ronström
> 
> 
> 
> 
> 
> 
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