JSFiddle - React, Tailwind, and code Playground

by Ajith S Punalur

HTML

<div class="container A">
  <svg class="typeRange" height="165" width="330" view-box="0 0 330 165">

    <g class="scale" stroke="red"></g>

    <path class="outline" d="" />
    <path class="fill" d="" />
    <polygon class="needle" points="220,10 300,210 220,250 140,210" />
  </svg>
  <div class="output">30</div>
</div>

<p>You may change the initial value by dragging over the gauge
  <br>or by editing the input below:</p>
<input type="text" class="initialValue" value="18" />

CSS

/*GREENS: #4ac4ac, #399988, #0f4534, #0a1a17;*/

* {
  margin: 0;
  padding: 0;
}

body,
html {
  width: 100%;
  height: 100%;
  margin: 0px auto;
  background-color: #0a1a17;
  font-family: Verdana, Geneva, sans-serif;
  font-size: 12px;
  color: #ccc;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-align: center;
}

.container {
  position: relative;
  margin: 100px auto 50px auto;
  height: 165px;
  width: 330px;
}

.output {
  line-height: 35px;
  width: 60px;
  height: 30px;
  background-color: #0f4534;
  border-radius: 60px 60px 0 0;
  position: absolute;
  top: 135px;
  left: 135px;
  text-align: center;
}

.initialValue {
  border: none;
  border-bottom: 1px solid #399988;
  color: #399988;
  display: block;
  width: 3em;
  background-color: transparent;
  margin: 1em auto;
  outline: none;
  font-size: 16px;
  text-align: center;
}
/*SVG*/

svg {
  margin: 0px;
  padding: 0;
  cursor: pointer;
  border: 1px solid #0a1a17;
}

svg.focusable {
  border: 1px solid #0f4534;
}

.outline,
.fill,
.center,
.needle,
.scale,
.output {
  pointer-events: none;
}

.outline {
  fill: #0f4534;
}

.fill {
  fill: #399988;
}

.needle {
  fill: #aa0000;
}

.scale {
  stroke: #aaa;
}

text {
  text-anchor: middle;
  dominant-baseline: alphabetic;
  font: 12px verdana, sans-serif;
  fill: #aaa;
}

JavaScript

var containersRy = document.querySelector(".container");
var svg = document.querySelector(".typeRange");
var output = document.querySelector(".output");
var outline = document.querySelector(".outline");
var fill = document.querySelector(".fill");
var center = document.querySelector(".center");
var needle = document.querySelector(".needle");

var initialValue = document.querySelector(".initialValue");

var rad = Math.PI / 180;
var NS = "http:\/\/www.w3.org/2000/svg";

var W = parseInt(window.getComputedStyle(svg, null).getPropertyValue("width"));
var offset = 40;
var cx = ~~(W / 2);
var cy = 160;

var r1 = cx - offset;
var delta = ~~(r1 / 4);

var initVal = initialValue.value;

var isDragging = false;

var x1 = cx + r1,
  y1 = cy;
var r2 = r1 - delta;

var x2 = offset,
  y2 = cy;
var x3 = x1 - delta,
  y3 = cy;

function drawScale() {
  sr1 = r1 + 5;
  sr2 = r2 - 5;
  srT = r1 + 20;
  var scale = document.querySelector(".scale");
  clearRect(scale)
  var n = 0;
  for (var sa = -180; sa <= 0; sa += 18) {
    var sx1 = cx + sr1 * Math.cos(sa * rad);
    var sy1 = cy + sr1 * Math.sin(sa * rad);
    var sx2 = cx + sr2 * Math.cos(sa * rad);
    var sy2 = cy + sr2 * Math.sin(sa * rad);
    var sxT = cx + srT * Math.cos(sa * rad);
    var syT = cy + srT * Math.sin(sa * rad);

    var scaleLine = document.createElementNS(NS, "line");
    var scaleLineObj = {
      class: "scale",
      x1: sx1,
      y1: sy1,
      x2: sx2,
      y2: sy2
    };
    setSVGAttributes(scaleLine, scaleLineObj);

    scale.appendChild(scaleLine);

    var scaleText = document.createElementNS(NS, "text");
    var scaleTextObj = {
      class: "scale",
      x: sxT,
      y: syT,
    };
    setSVGAttributes(scaleText, scaleTextObj);
    scaleText.textContent = n * 10;
    scale.appendChild(scaleText);

    n++

  }

}

function drawInput(cx, cy, r1, offset, delta, a) {

  var d1 = getD1(cx, cy, r1, offset, delta);
  var d2 = getD2(cx, cy, r1, offset, delta, a);

  drawScale();

 ...