Enhancement: add support for semi-transparency
Originally reported by: ebe123
Currently, the transparency property is a boolean,
as PostScript does not support alpha transparency.
However, SVG does support transparency using an alpha
channel. To use this capability effectively, the
property should be real
between 0 and 1. The
property would have to be converted to a boolean
for incompatible backends, like PS
, but added as
a color channel. This would allow transparent objects
to be examined, not just omitted but keeping spacing.
Original URL: https://sourceforge.net/p/testlilyissues/issues/5189
Edit by Valentin (2020-05-23), moved here by Jonas (2020-12-07):
Alpha transparency can be used in SVG backend through the
'color
property (issue #5984 (closed)), but there is currently no
way of obtaining semi-transparency regardless of the grob’s color.
ebe123 posted a proposal to take advantage of the 'transparent
property by making it accept “real” numbers between 0 and 1:
quote of the original description (see above)
See my comment below for another possible implementation.
The question of whether and how that can be supported in
backends other than SVG yet remains to be solved.