Another notable figure in the world of drawing music is Norman McLaren, who literally painted or drew directly on the soundtrack portion of his animated films.
The soundtrack for his film Neighbors , which won an academy award in 1952, was produced this way.
Theres a short documentary on his process here .
On the more avant-garde side, Iannis Xenakis had designed a computer-based system called the UPIC in the late 1970s in which you could directly draw waveforms and then direct their frequencies over time by drawing into a graphics tablet.
He used this to compose his piece Mycenae Alpha .
This page  has a really great run-down of optical synthesis in general, which includes a number of individuals and systems involved in directly drawing sound and music.
Some of the visual sound designs used in these systems are quite striking, for instance the variophone  or Yankovsky's painted soundtracks .
 Demo of my research software here: https://www.youtube.com/watch?v=Tdj5e82nPHQ
The synthesizer is available here : https://www.fsynth.com
One wonders what Daphne would have thought of tools such as yours, and as well of course things like U&I's MetaSynth:
Maybe Ill post a Show HN here when I publicly release the app over the summer.
Not sure which machine came first, but around the time of the UPIC system you mentioned the Fairlight CMI was released, which (amongst its other functions) allowed users to draw out waveforms using a lightpen:
This video shows Peter Gabriel playing around with a Fairlight CMI, from what I remember I don't think it shows the waveform drawing but it gives some idea of what it was capable of:
FWIW The most general wikipedia article and category that comes close to covering what you describe as "optical synthesis" is
The page emphasises the optical film soundtrack (on celluloid) as a medium for experimentation, which is something I'm fascinated by.
The gender aspect is interesting too, maybe related to ideas like Papert and Turkle's. There are at least two female film artists who have done interesting critical work with the optical film track:
also, in a different way,
whose work has, AFAIK, included providing replica tapes for the Oramics machine when it was displayed at the Science Museum.
There's also of course the very famous and female Delia Derbyshire, working in a similar milieu to Oram, but without pursuing the graphical aspect.
I'm sure you're aware of this, but for the record, there's a physical archive of Oram material at Goldsmiths in London:
The man in charge is Mick Grierson, an old Dorkbot London hand.
Your software looks excellent. Very intuitive version of what others try to do textually
On slide 16 of that set Hudak uses the dreaded Haskell monads (well, arrows) to compose a synthesis setup (a model of a flute), but it's an excellent example of something that could be done so much less opaquely in a graphical environment like yours)