[Denemo-devel] DENEMO_OVERRIDE_GRAPHIC applied to chord directives.

[Richard Shann]

We recently defined a meaning for DENEMO_OVERRIDE_GRAPHIC applied to
chord directives. We said that it meant the the graphic supplied with
this override was to be used for each note of the chord. This was to
avoid having to attach directives to every note of a chord; doing this
means that a lot of Denemo's actions with notes on chords can be used
for chords of Breves etc.
What we didn't define was the more obvious meaning for a graphic on a
chord, namely, replace the displayed graphical drawing of the chord. We
need this for things that we want Denemo to treat as a chord but which
we want to display in some user-defined way. The example I have in mind
is polyphonic rests. A rest, in Denemo, is a chord with no notes. A
polyphonic rest is a rest which is positioned like a note (higher or
lower in the staff depending on a hidden note name). (This is the
LilyPond representation in fact, which it will be convenient for us to
adopt in Denemo).
For this case we want to replace the display of the chord (including
stems and beams) with a graphic (which we will choose depending on the
duration of the chord we are modifying). So we need another sort of
graphic override for this. To keep things neutral (we may want
alternative overrides for other types of directives) I propose to define
a DENEMO_ALT_OVERRIDE flag. The meaning is that the usual meaning of the
overrides takes some alternative meaning.
So applied to chord directives the complete disabling of normal display
for the chord and its replacement by the directive's graphic would be
signalled by setting DENEMO_OVERRIDE_GRAPHIC, while the specialized
"replace all noteheads" meaning would require DENEMO_ALT_OVERRIDE to be
set as well.
This means changing the scripts that have been developed (recently) to
use DENEMO_OVERRIDE_GRAPHIC on a chord so that they use (logior
DENEMO_OVERRIDE_GRAPHIC DENEMO_ALT_OVERRIDE).
We could, of course, switch the meanings around, but this would remain
an somewhat curious naming convention.
I think Nils is the only one involved here (?) but anyone with an
opinion can comment

Richard