On Beams

Beams are interesting. Engraving rules for beams are extremely inconsistent. In essence, the ideal rendering involves striking a balance between the direction of the music, the angle of the beam, and the length of the stems. You don't want beams whose absolute slopes are too high, and you also don't want to compromise on the slopes too much by making the stems too long.

There is one well-known rule, however: Never shorten a stem.

Beams on Both Voices

The algorithm I currently use to render beams seems to work pretty well. I use an approach where I iteratively update the slope and y-shift of the beam, based on the height of each stem.

In retrospect, this algorithm seems pretty obvious, but I really had to experiment a fair bit to derive it. The first few beams were just all over the place.

Beam Confusion

More Beam Confusion

My debugging code places colored dots at various control points to help me visualize the errors better. It took me a bit of effort before I got to the rendering below. The beams still aren't shifted far enough to both accommodate for the stem heights.

Close... But Still Wrong!

After ironing out the iterative algorithm, I got this:

Decently Rendered Beams

Perfect! The stems are only extended where necessary, and the angles of the beams adequately reflect the direction of the music.

Thanks to the context-based architecture, note-modifiers such as accidentals don't disturb beam positioning.

Beam With Accidentals

That said, something about the above rendering does not look right to me. The group of eighth notes don't look like they're positioned very evenly. If anyone knows how to render beamed notes with accidentals correctly, please let me know.

Anyhow, I also got slides and ties working again. These were gone after the rewrite, and I had to work them in using the new framework.

Tab Slides

Hammer-Ons

These actually make use of annotation-contexts which help determine the position of the annotation text above the stave.

Random Annotation

I'm still a bit unsure of how to render ties across different note steps, with accidentals. What I have now looks like this:

Chord Ties

Although this is a really uncommon case, it would be nice if there were a generic way to deal with it. Thoughts? Ideas?

That's all for now folks, and thanks very much for the comments. Keep 'em coming!