I developed an intuitive interface for music notation.
I created this to facilitate picking notes for the fingering chart apps, and have utilized it in most every app since.
The instinctive gesture of touching the staff seemed so natural, and then to slide right for sharp and left for flat was simply the next step.
To make it easier to choose sharps or flats, I decided that touching along the right or left side would be a natural progression to automatically set a sharp or flat note.
The formulas for manipulating the images of notes and accidentals has developed over time, becoming more versatile and streamlined with each implementation.
Twelve Tone introduced the ability to notate more than one note on the same staff. Up to twelve actually. So I had to isolate the controls for each note to its own area. This opened up more opportunities and I eventually incorporated it, and rhythmic values, into Woodshed to allow the creation of custom exercises. Implementing more complexity with rests, barlines, and pickup notes created Melody Composer. Note values and triplet figures automatically tie and extend over barlines. Notation should serve the music you want, not dictate it. There are limitations to Melody Composer, but it's a handy tool for composers.
Twelve Tone, Vocal Exercises and the Scales Lexicon apps all show the next stage in the animation of the notation. If a user could select a note, it's pretty obvious that I should be able to have the app select one. Let's just change the color and do it over and over in a rhythmic pattern. And while we're at it, let's do that to the piano as well.
Music Theory Intervals and Music Theory Chords were the next steps. There are specific notational rules when writing chords. The accidentals need to appear in a specific order and spacing from the note, or it just seems wrong. When the rules aren't followed, it's much more difficult to read and becomes something that's getting in the way of music rather than expressing it. I was a copyist all through college, back when people actually wrote out music with a fountain pen and india ink. Finale software was just starting and writing was still faster and easier. The wonderful Osmiroid 65. Well, I digress and date myself.
Correct notation is essential to conveying music and to display chords with ugly and disconnected accidentals was just not going to happen. An Fb diminished seventh chord is spelled with double and triple flats. Using enharmonics, it becomes a different chord. It may sound the same, but it's not an Fb diminished seventh. I guess I'm a theory geek, but these things are important to me.