2dnote

_2DNote: 2D Note Generator

Live Demo

Include in HTML

API

Purpose: An experiment in making visual interfaces more accessible to people who are blind. Screen readers linearize your page content, so they don't communicate 2-dimensional visuals very well. You can address that by mapping 2D positions to notes.

Potential Uses: Create 2D games and apps that people can use together, regardless of vision capabilities? Hear the contours of your signature as you write it? Enable people to "hear" what someone else is drawing? Locate elements on a page? Convert graphs into sound? Etc.

Some Design Choices: _2DNote does not rely on binaural audio, so devices with only 1 speaker can still communicate the 2D position of one or more elements simultaneously. It does that by relying on volume and pitch. Brain plasticity will take care of the rest.

You can think of the y dimension as the "proximity dimension" (louder = closer to you), and the x dimension as the "piano dimension" (left-to-right = low-to-high notes).

_2DNote.js is made from pure "vanilla" JavaScript. So no extra dependencies. :smile:

Further reading

• Sonification
• Auditory display

Live Demo

https://codepen.io/hchiam/full/eYYdVeX

(You can live edit the demo code in real time here: https://codepen.io/hchiam/pen/eYYdVeX)

Can I include it in my own HTML code?

Yes:

<script
  src="https://cdn.jsdelivr.net/gh/hchiam/_2DNote@1.12.0/_2DNote.min.js"
  integrity="sha384-WdS+mavw33iD6+LA5WvOOdklYxzu60nE9DdK9RlJITvWzSJPeF8pF1ln7VrWa+yC"
  crossorigin="anonymous"
></script>

While not recommended, you can auto-update to the latest by linking the src to:

• https://cdn.jsdelivr.net/gh/hchiam/_2DNote@master/_2DNote.min.js or
• https://cdn.jsdelivr.net/gh/hchiam/_2DNote@latest/_2DNote.min.js

By including _2DNote.js, you get an object _2DNote, which you can use in your HTML or JS code.

For example:

<div onmousemove="_2DNote.update(event,colourSoundIcon);">...</div>

For quick setup on the body tag:

<body>
  <script
    src="https://cdn.jsdelivr.net/gh/hchiam/_2DNote@1.12.0/_2DNote.min.js"
    integrity="sha384-WdS+mavw33iD6+LA5WvOOdklYxzu60nE9DdK9RlJITvWzSJPeF8pF1ln7VrWa+yC"
    crossorigin="anonymous"
  ></script>
  <script>
    _2DNote.setAs2DArea(document.body, callbackUponUpdate);
    function callbackUponUpdate() {
      // do something whenever _2DNote.update() is triggered;
    }
  </script>
</body>

For quick setup of a custom 2D click/touch area:

<body>
  <div id="2d-area" style="width: 100vw; height: 100vh;">...</div>
  ...
  <script
    src="https://cdn.jsdelivr.net/gh/hchiam/_2DNote@1.12.0/_2DNote.min.js"
    integrity="sha384-WdS+mavw33iD6+LA5WvOOdklYxzu60nE9DdK9RlJITvWzSJPeF8pF1ln7VrWa+yC"
    crossorigin="anonymous"
  ></script>
  <script>
    _2DNote.setAs2DArea(document.getElementById("2d-area"), callbackUponUpdate);
    function callbackUponUpdate() {
      // do something whenever _2DNote.update() is triggered;
    }
  </script>
</body>

To disable the "exit" sound:

var useExitDetection = false;

_2DNote.setAs2DArea(
  document.querySelector("#your_element"),
  callbackUponUpdate,
  useExitDetection
);

For a full working code example, see example-include.html

Here's an example of 2 notes playing simultaneously: example-two-notes.html

API

The things you're most likely to use are: .play(e), .update(e), .stop(), and .copy().

(Full details in _2DNote.js.)

_2DNote.audioContext:

• This is the AudioContext used by the _2DNote instance to do the work of actually creating the note.

_2DNote.note:

• This holds the information about the note (oscillator, volumeSetup) that the _2DNote instance can play.

_2DNote.play(e, setupExitDetection = true):

• This plays a note based on the position of the element or mouse click event, which it figures out for you. (e is for event or element.)
• setupExitDetection is an optional parameter, and is true by default. You most likely will want to do either _2DNote.play(e) or _2DNote.play(e, false). This parameter tells _2DNote whether it should play an "exit" sound when you leave the 2D area.
• Note: The note automatically stops playing if the cursor moves outside the window. This avoids having users click something outside the window without realizing it.
• UX reminder: If you plan to use _2DNote in only one area of the page, you should let users know when the cursor moves outside of that area. To do that, try something like <tag-name onmouseleave="_2DNote.stop();"> on the enclosing HTML element tag. See example-include.html or example-two-notes.html for examples placed on the body tag. If you'd like to disable the warnExitedView when the mouse leaves the body, then you can run document.body.removeEventListener("mouseleave",_2DNote.warnExitedView);

_2DNote.update(e) or _2DNote.update(e, callback):

• This causes the note that the _2DNote instance is playing to update to the current position of the element or mouse click event, which it figures out for you. (e is for event or element.)
• callback is an optional parameter, and is a function that will be run from within update() with this signature: callback(volume, frequency, pan). See full details in _2DNote.js. See usage example in example-include.html or example-two-notes.html.

_2DNote.stop():

• This stops the note that the _2DNote instance is currently playing.

_2DNote.copy():

• This returns a deep clone of the _2DNote instance. Extra instances make it more convenient to play multiple notes at the same time.

_2DNote.getFrequency(e):

• This returns the note frequency based on the x coordinate of the element or mouse click event, which it figures out for you. (e is for event or element.)

_2DNote.getVolume(e):

• This returns the note volume based on the y coordinate of the element or mouse click event, which it figures out for you. (e is for event or element.)

_2DNote.getPan(e):

• This returns the note panning based on the x coordinate of the element or mouse click event, which it figures out for you. (e is for event or element.) Panning creates binaural audio: if you use headphones, it'll sound like the audio is coming from the left or right side of you.

_2DNote.normalize(value, inputRange, outputRange):

• This maps the value found within the input range ([inputRangeMin, inputRangeMax]) to be in the chosen output range ([outputRangeMin, outputRangeMax]). It returns the re-mapped value.

Also available on NPM

https://www.npmjs.com/package/2dnote

npm i 2dnote

See the notes in this example to publish to both GitHub packages page and npm packages page: https://github.com/hchiam/generator-hchiam-learning/commit/f3bbdfa93ae7c27e8d32b04f587afc644048e486

If you're interested in general accessibility

https://github.com/hchiam/web-accessibility-course-notes#web-accessibility-a11y-course-notes

Other accessibility-related repos

https://github.com/hchiam/flying-focus

https://github.com/hchiam/keyboard-focus-trap

Local development

bash package.sh