wc-slider (An alternative to the range input)

By Maksim Chernyshev

HTML is brilliant; it's an ever-growing standard; CSS is also pretty amazing! I say this because I was bored over the evenings this week and brushed off an old thing I started years ago to help me with the inability to style range inputs. You can do some cool styling on range inputs now, but when I created my initial component, it wasn't easy and involved many vendor prefixes, with some target browsers unable to handle even those. So I decided to write a component to get our designer's desired effect.

But I was bored this week, so I decided to revisit it; you can see the result on JSFiddle.

It was a lot of fun doing this, I'm not sure if I'll ever need it again, but it was a valuable learning experience. Asking for help from a mate meant that she could echo back something I've said to her many times before: "Have you tried flex?", so embarrassing, but it just goes to show! One issue was that I was sticking to the original CSS too much and didn't have to cope with variable-sized wc-sliders. You see, the little arrows behind the slider element moved depending on the number of elements in the slider.

The Drag-and-Drop mechanism took the most time and - as a result of checking my workings - I clocked I was using the getters for range, colourRange and deselectedRange far too much. I moved these to Private class features and only calculate them on render(). Thanks to the dictates of working with a designer, I also spent a fair bit of effort working with colours and gradients - a bit of a ballache, TBH, but I've got the functions now so that I can use them again in the future!

I do like the invertColor(hex, bw) though. That's tremendous fun and might be useful should you check what colour you need to set text atop different coloured backgrounds. Looking at it again now, though, I think the none bw might be a little borked; I'll fix it as and when I've time.

It's a bit CSS-heavy, but no worse for that, TBH; if you can do something with CSS, then it's better than firing up JS - let the browser do the work!

From the README:

• Dragging the slider element will alter the value surfaced by the component from its value attribute (should the number in which the drop ends be greater than or equal to the constrain-min or less than or equal to the constrain-max)
• Clicking on the numbers shown at the top of each step will alter the value surfaced by the component from its value attribute (should the number be greater than or equal to the constrain-min or less than or equal to the constrain-max).
• Clicking on the triangles on either side of the slider will alter the value surfaced by the component from its value attribute by +/- 1 (should the number resulting from the click be greater than or equal to the constrain-min or less than or equal to the constrain-max).

As you can doubtless see, there are three ways of changing the value and - given the work I put into checking the bugger, no way for an invalid value to be produced - though you might not like the value. Having said that, if you manage to break it, please let me know, so I can fix it!

It has some default attributes so that you can test it for your use case.

Again, from the README:

• The range of numbers, inclusive of min and max, should not be too large - tests have found that the ranges should not have more than 15 numbers, but YMMV.

One thing to consider in the future is whether or not to allow for a comma-separated list of hex values so that designers can adequately define what colours should appear on the wc-slider.

Fixing the Donut

By Jessica May

I've been playing with a pie-chart web component for a little while now, and I was thrilled with the result... until I started to use it in anger, that is.

The thing was, angles over 180 messed something up - I decided to revisit it this week after reading this article by Temani Afif, and I'm once again thrilled to see it working - and working correctly (at least in Chrome and Edge):

class DMPieChart extends HTMLElement {
  static get observedAttributes() {
    return [
      'width',    // width of the chart
      'duration', // duration of the animation
      'delay',    // delay before the animation
      'thickness' // thickness of the slices
    ];
  }
  get style() {
    return `
      <style>
        * {
          box-sizing: border-box;
        }
        div {
          width: ${this.width}px;
          height: ${this.width}px;
          position: relative;
        }
      </style>
    `
  }
  constructor() {
    super()
    this.shadow = this.attachShadow({
      mode: 'closed'
    })
    this.shadow.innerHTML = `
      ${this.style}
      <div>
        <slot name='pie-slices'></slot>
      </div>
    `
    try {
      window.CSS.registerProperty({
        name: '--p',
        syntax: '<number>',
        inherits: true,
        initialValue: 0,
      })
    }catch (e) {
      console.warn('Browser does not support animated conical gradients')
    }
  }
  connectedCallback() {
    const segments = [...this.querySelectorAll('dm-pie-slice')]
    const total = segments.reduce((p, c) => p + Number(c.getAttribute('value')), 0)
    let durationTotal = this.delay;
    let rotationTotal = 0
    const totalDegree = 360/total

    segments.forEach(segment => {
      const value = Number(segment.getAttribute('value'))
      const currentRotation = totalDegree * value
      const animationDuration = currentRotation / (360/Number(this.duration))
      segment.setAttribute('thickness', this.thickness * this.width)
      segment.setAttribute('end', (value / total) * 100)
      segment.setAttribute('rotate', rotationTotal)
      segment.setAttribute('delay', durationTotal)
      segment.setAttribute('duration', animationDuration)
      segment.setAttribute('width', this.width)
      rotationTotal += currentRotation
      durationTotal += animationDuration
    })
  }
  get width() {
    return Number(this.getAttribute('width')) || 150      // 150px by default
  }
  get duration() {
    return Number(this.getAttribute('duration')) || 5000  // 5 seconds by default
  }
  get delay() {
    return Number(this.getAttribute('delay')) || 500      // half a second by default
  }
  get thickness() {
    return Number(this.getAttribute('thickness')) || 0.2   // 60% of width by default
  }
}

class DMPieSlice extends HTMLElement{
  static get observedAttributes() {
    return [
      'width',      // width of the chart
      'duration',   // duration of the animation
      'delay',      // delay before the animation
      'color',      // color of the arc
      'thickness',   // thickness of the arc
      'rotate'      // how far to rotate the arc
    ];
  }
  get style() {
    return `
      <style>
        * {
          box-sizing: border-box;
        }
        div {
          --p: ${this.end};
          width: ${this.width}px;
          aspect-ratio: 1;
          margin: 0;
          position: absolute;
          left: 50%;
          top: 50%;
          animation-name: p;
          animation-fill-mode: both;
          animation-timing-function: ease-in-out;
          transform: translate(-50%, -50%);
          animation-duration: ${this.duration}ms;
          animation-delay: ${this.delay}ms;
        }
        div:before {
          content: "";
          position: absolute;
          border-radius: 50%;
          inset: 0;
          background: conic-gradient(from ${this.rotate}deg, ${this.color} calc(var(--p)*1%), transparent 0);
          -webkit-mask: radial-gradient(farthest-side, transparent calc(99% - ${this.thickness}px), #000 calc(100% - ${this.thickness}px));
          mask: radial-gradient(farthest-side,#0000 calc(99% - ${this.thickness}px), #000 calc(100% - ${this.thickness}px));
        }
        @keyframes p {
          from {
            --p: 0
          }
        }
      </style>
    `
  }
  constructor() {
    super();
    this.shadow = this.attachShadow({
      mode: 'closed'
    })
    this.shadow.innerHTML = `${this.style}<div/>`
  }
  get width() {
    return Number(this.getAttribute('width')) || 150      // 150px by default
  }
  get duration() {
    return Number(this.getAttribute('duration'))
  }
  get delay() {
    return Number(this.getAttribute('delay'))
  }
  get color() {
    return this.getAttribute('color') || '#000000'        // black by default
  }
  get thickness() {
    return Number(this.getAttribute('thickness'))
  }
  get rotate() {
    return Number(this.getAttribute('rotate'))
  }
  get end() {
    return Number(this.getAttribute('end'))
  }
}

window.customElements.define('dm-pie-chart', DMPieChart)
window.customElements.define('dm-pie-slice', DMPieSlice)

It is significantly cleaner but only animates within Chrome and Edge (everywhere else, it should just appear without animation, which is a shame).

I've also moved away from using the CSSStyleSheet interface as Safari throws a wobble when it's used without a polyfill, which is a shame as constructible/adoptable style sheets rock!

The animation is thanks to @property CSS at-rule. It is utterly brilliant, especially once I understood you could inject it via JS, as injecting it into the component's CSS didn't work at all - either via the static CSS or the constructible/adoptable CSS.

Bundling it into one file should also ease its adoption.

Sierpiński triangle

I was scrolling through TikTok a couple of evenings ago (I know, I'm probably far too old to do so, but now and again, there's gold!) and I came across the following video:

@flipperzer0

♬ Levels - Live Session - Sarah Coponat

Anyway, inspired to give it a go, I worked up a p5 test, and it works!

const points = [
  [-75, 130],
  [-150, 0],
  [-75, -130],
  [75, -130],
  [150, 0],
  [75, 130],
]

const rand = (int) => Math.round(Math.random() * int)

const width = 600
const height = 600


function setup() {
  createCanvas(width, height)
  noStroke()
}

function draw() {
  background(0)
  fill(255, 255, 255)
  text(points.length, 50, 50)
  points.forEach(point => {
    circle(point[0] + (width /2), point[1] + (height /2), 1)
  })
  if(points.length === 6){
    const target = points[rand(6)]
    const source = points[0]
    points.push([
        (source[0] + (2/3 * (target[0] - source[0]))),
        (source[1] + (2/3 * (target[1] - source[1])))
    ])
  }else{
    populateArray(1000, points)
  }
}

const populateArray = (count, arr) => {
  for(let i = 0; i < count; i++){
    const target = points[rand(6)]
    const source = points[points.length - 1]
    points.push([
      (source[0] + (2/3) * (target[0] - source[0])),
      (source[1] + (2/3) * (target[1] - source[1]))
    ])
  }
}

for some unknown reason, and only every so often, the pattern goes wrong; does anyone have any idea why or how to fix it?

Sorting colours is a pain!

By Garrick Ang

I've written before about sorting colours, and this got me thinking about some work I'm doing in terms of converting some CSS to SCSS (with the proper use of CSS variables, I must add).

As such, I've been wading through some CSS, extracting colours, and then popping them into a :root CSS pseudo-class. I do this by looking for `#` and popping the colour into the function as and when I find them. The resulting text is well messy! I thought it couldn't be that hard to sort them similarly as employed in Google Sheets; so I came up with CSSColourSorter, which you're more than welcome to use or steal/borrow as you see fit.

It works by pasting in your whole :root directive - you'll then need to copy and paste the resulting test into your CSS/SCSS as noted before, though, sorting colours is a pain!

I've added a swatch beneath the textareas so you can see the new spectrum - mainly to check that I was doing things right!