Re: Animated SVG Percussion Music

[Patrick McCarty]

On 2011-09-30, Jay Anderson wrote:
> This doesn't seem feasible for for multiple voices and multiple
> staves. Could the svg backend be changed to optionally add in some
> metadata about the pitch, moment, duration, voice etc.?

IIRC, it's only possible to find this information through the
'grob-cause' stencil expression.  In the SVG backend this stencil
expression is a noop, but the PS backend uses it to embed the
point-and-click metadata.

> The dump-path function in output-svg.scm is where note heads (and a
> few other things like clefs) are added, but I'm having a hard time
> tracing it backwards from there. It looks like at some point the
> music is put into an intermediary format and is parsed with a bunch
> of regular expressions.  Can someone point me to where this
> intermediary is created or provide some more information on how the
> svg back-end is called?

If you want to trace the program flow, start at the procedure
definition for 'embedded-glyph-string' (output-svg.scm:437) and work
your way north in that file :)

Here are some hints for you:

The embedded-glyph-string procedure is called (indirectly through
'glyph-string') every time it appears in a page stencil.  The
arguments are the font smob, font size, cid boolean value (irrelevant
for SVG), and a list of glyph names.

After the font file name is determined, an SVG font is loaded and
glyphs are extracted from it (with help from regular expressions).
'dump-path' is the final step where SVG path elements are generated
with the appropriate path info.


Hope this helps!

Regards,
Patrick