Welcome to clap. A front JS Selector for rgba color level manipulation.

Add clap.js in your sources and call it in your code. Add a div that will be populated by the controller.

<div id='colorLevel'></div>
<script src="clap.js"></script>
<script>
    let container = document.getElementsById('colorLevel');
    let id = "YourCustomId";
    let settings ={
          "width":1200,
          "height":50,
          "background":"#000000",
          "margin":15
      }
    new Clap(container, id, settings);
</script>

The instanciation of the class takes 3 parameters.
container DOM obj (mandatory): The DOM element that will contain the Clap Controller.
id String (not mandatory but you must pass one): The id given to the instance will take the form "color_level_"+id.
settings Object: object containing the customized values.

You can customize the following settings.
Only one or some of the values can be passed as parameter.

The other ones will take the defaults values :

width=120;
height=120;
background="#AAAAAA";
margin=10;
min=0;
max=255;
lineWidth=2;
handlerSize=10;
boundary=false;
boundaryColor="#FFFFFF";
gradient=false;

width Int: width of the containing canvas. (default 120)
height Int: height of the containing canvas. (default 120)
background String: Color in HEX format. (default #AAAAAA)
margin Int: Value in pixel of the margin around sliders. (default 10)
min Int: Minimun value in mapping scale. (default 0)
max Int: Maximum value in mapping scale. (default 255)
lineWidth Int: Line Width in pixel of handlers shape. (default 2)
handlerSize Int: Size in pixel of handlers' sides. (default 10) boundary Boolean: Switch display/hide of handlers limits (default false)
boundaryColor String: Color in HEX format. (default #FFFFFF) gradient Boolean: Switch display/hide of gradient over color sliders (default false)

IMPORTANT : min have to be strictly inferior than max.

On change the Clap instance triggers a custom event clap_change which bubbles through the DOM.
You can subscribe to this event as follow :

document.addEventListener('clap_change', (evt)=>{
    console.log(evt.colorLevels);
})

You can get evt.colorLevels to get the values.
For now you can interract with rgba values (in and out).
Default min value is 0.
Default max value is 255.

Eyes at the bottom of slider are for hide/display mechanism purpose. Click on it to switch beetween modes.
If you want to interact with a layer, click on its letter. If a layer is active the leter will be uppercase.
Click on the handlers drawn on vertices and move the mouse while holding mouse down to move it.

Please check that your git version is above or equal to 2.9.

git --version

As this project uses dependencies you need to have npm installed.
You can install it by installing Node on your computer.
You can find more info about this subject here:
https://nodejs.org/en/

To setup the project, put yourself in repository root and run :

./setup.sh

It will install the node modules and setup the pre-commit hook.

You can read TODO.md to see what have to be done and contribute.