Jason Gedge

Data + Rendering -- Design Decisions

Posted on September 20, 2011

Sorry for the lack of posts over the summer, but it was my time to just relax and do very little after a lot of hard work to finish my M.Sc. thesis. I’ve finally gotten a start on score rendering (see image below). I’m currently at an interesting point where I have to make a design decision. For a part in a score there can be multiple staves. For example, a piano score usually has two: one for treble clef and one for bass clef. For guitar tabs, there is often the tablature and then the score notation affiliated with this tablature.

My design decision is focused on the best way to structure my data hierarchy and rendering process to render this. In particular, I’m focused on tablature. The tricky thing here is the fact that the score and the tab are two different views of the same data. I have considered two possibilities:

  1. Consider score and tablature two different staves that reference the same set of data. This comes with a set of things to think about:
    • Pros
    • The rendering process can blindly render everything.
    • Cons
    • Other parts of the program should know that these refer to the same set of data (e.g., when saving to file).
    • Right now my data hierarchy is represented using a parent/child relationship. Since these two staves point to the same set of bars, each bar would technically have two parents. I’d rather not change the way things are currently, so I would just have to make sure that in no situation it would be a problem getting the initial parent.
    • User will most likely have to manually remove these staves. In other words, it might not be easy to implement a “Show Score/Show Tablature/Show Both” option. Maybe this isn’t really much of a con?
    • Without any code that remembers the connection between the two staves, the user would be able to insert another staff in between them. Now if the user chooses to do this, it’s his/her own choice so this may not be a bad thing, but it breaks up the connection between the two and the fact that they are connected (i.e., by the same data). Again, maybe this isn’t really a con?
  2. Restrict this merely to the rendering process
    • Pros
    • Does not require any changes to the data hierarchy.
    • Cons
    • Less flexible.
    • Most likely will produce sloppier rendering code.
    • Code for user interaction would be uglier. For example, when the user clicks on the score rendering component, I need to figure out which staff is clicked. I would have to write code that checks the view type (score/tab/both) and understands that some staves would be rendered twice in the “both” viewing mode.

It’s just one of those bigger decisions I have to make early. I’m pretty sure I’ll go with the first one, but I’d like to hear thoughts and/or suggestions from other people (who I haven’t confused yet).

And for those who want to see my latest work, click here to get a feel for the current state of score rendering. It’s just the basics for now (note heads/stems), so I have a lot of work to do still (e.g., beams, grace notes).

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