Re: Beam direction property

On Wed, Jul 13, 2016 at 4:36 PM, Andrew Bernard [via Lilypond] <[hidden email]> wrote:

Hi Abraham,

Thanks for the suggestion. Since lilypond internals are not documented nicely, in terms of plain examples and behaviour, you just have to use trial and error to code these things (unless there is a Secret Book I am unaware of…). Using the beam seems to work better for the right hand case nad for my way of doing it, for reasons too long to explain just here. I still need to know what the Beam.direction property is, and why it can’t be set, and what it represents. It is this sort to information that that NR and IR lack, frustratingly,

Things like knowing a beam has a stems object. How does one find out about things like this, without reading al the source code, and trying to figure that out?

I do need the beam information and understanding because there are other beam modifications I want to make as well involving changing the beam shape in certain ways.

Believe me, I understand your frustration. Here are a couple of things I've learned about the IR:

1. The "Standard Settings" table on grob's web page are all grob properties that have been defined in "define-grobs.scm" or internally in the C++ source code.

2. At the top of each grob's web page is shows which engraver(s) creates the grob. Clicking on the engraver links leads to a page that shows engraver properties that you can modify to adjust the engraver's procedure.

3. At the bottom of each grob's web page it shows the interface(s) that affect the grob, including generic ones (e.g., font-interface) and some grob-specific ones (e.g., beam-interface) though the grob may not know how to use all user-settable properties in each of these interfaces. Clicking on the interface link(s) leads to more grob properties that you can access/change via ly:grob-property and ly:grob-set-property!, respectively. Towards of the bottom of the interface web page will be a "Interface Properties" table that lists various objects that the grob has access to. This is where you find out that a Beam grob has a 'stems object you can access via ly:grob-object.

In this particular case, you can access the 'stems from the Beam grob or, vice-versa, the 'beam from the Stem grob. You pick.

HTH,

Abraham

From:	tisimst
Subject:	Re: Beam direction property
Date:	Wed, 13 Jul 2016 15:53:39 -0700 (MST)