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HTML Settings

Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

            
              <svg viewbox='-1000 -500 2000 1000' class='frame'></svg>
<div class='controls'>
  <input class='n-slider' type='range' min='3' value='3' max='26'>
  <input class='n-text' type='text' value='3'>
</div>
            
          
!
            
              $brown: #312C24; // dark medium-dark
$bright-yellow: #FADF1D; // light highlight-light
$light-yellow: #F9DE4E; // light medium-light
$bright-pink: #BB1654; // dark highlight-dark
$dirty-white: #F1F1F1; // light base-light

* { box-sizing: inherit; }

html {
  box-sizing: border-box;
  background: black;
}

.circle {
  fill: none;
  stroke: white;
  stroke-width: 5;
  
  &__radius {
    stroke: $dirty-white;
    stroke-dasharray: 15;
  }
}

.polygon {
  cursor: pointer;
  
  &__edge {
    stroke: $bright-yellow;
    stroke-width: 5;
    
    &-midpoint {
      fill: $dirty-white;
    }
  }
  
  &__circle {
    stroke-dasharray: 10;
    
    &:hover {
      stroke-dasharray: 0;
    }
  }
  
  &__vertex {
    fill: $bright-pink;
    
    &:hover {
      stroke: $light-yellow;
      stroke-width: 5;
    }
  }
  
  &__centre {
    fill: $light-yellow;
  }
}

.controls {
  position: fixed;
  top: .5em;
  padding: .5em;
  background: $brown;
  color: white;
  
  input {
    padding: .25em;
    vertical-align: middle;
    
    &[type='range'] {
      cursor: pointer;
    }
    
    &[type='text'] {
      max-width: 3em;
      border: none;
      border-radius: .25em;
      box-shadow: 0 0 .25em black;
      background: transparent;
      color: white;
      text-align: right;
      
      &:focus {
        box-shadow: 0 0 .25em $bright-yellow;
      }
    }
  }
}
            
          
!
            
              var NS_URI = 'http://www.w3.org/2000/svg', 
    
    min = Math.min, 
    round = Math.round, 
    random = Math.random, 
    sqrt = Math.sqrt, pow = Math.pow, hypot = Math.hypot, 
    PI = Math.PI, cos = Math.cos, sin = Math.sin, 
    
    frame = document.querySelector('.frame'), 
    vb = frame.getAttribute('viewBox').split(' '), 
    w = ~~vb[2], h = ~~vb[3], 
    n_slider_el = document.querySelector('.n-slider'), 
    n_text_el = document.querySelector('.n-text'), 
    
    point_radius = 10;

/*
 * returns a random number between the min and max values
 * if min is omitted, it defaults to 0
 * if max is omitted, it defaults to 1
 */
var rand = function(max, min) {
  var b = max || 1, a = min || 0;

  return a + (b - a)*Math.random();
};

var setAttrs = function(el, o) {
  for(var a in o) {
    el.setAttribute(a, o[a]);
  }
};

var Point = function(x, y, r) {
  this.x = (x === 0 || x)?parseInt(x, 10):round(rand(frame.w));
  this.y = (y === 0 || y)?parseInt(y, 10):round(rand(frame.h));
  this.el = document.createElementNS(NS_URI, 'circle');
  
  this.el.classList.add('point');
  setAttrs(this.el, {
    'cx': this.x, 
    'cy': this.y, 
    'r': (r)?r:point_radius
  });
};

var Segment = function(start, end) {  
  this.start = (start instanceof Point)?start:(new Point());
  this.end = (end instanceof Point)?end:(new Point());
  this.el = document.createElementNS(NS_URI, 'line');
  
  this.el.classList.add('segment');
  setAttrs(this.el, {'x1': this.start.x, 'y1': this.start.y, 
                    'x2': this.end.x, 'y2': this.end.y});
  
  /* 
   * get the length of this segment
   * uses the start and end points
   */
  this.len = function() {
    var dx = this.end.x - this.start.x, 
        dy = this.end.y - this.start.y;

    return round(hypot?hypot(dx, dy):sqrt(pow(dx, 2) + pow(dy, 2)));
  };
  
  /*
   * the midpoint of the segment
   */
  this.midpoint = function() {
    return new Point(round((this.start.x + this.end.x)/2), 
                     round((this.start.y + this.end.y)/2), 
                     .7*point_radius);
  };
};

var Circle = function(type, radius, parent) {
  var radii_frag = document.createDocumentFragment(), b;
  
  this.centre = new Point(0, 0);
  this.radius = radius;
  this.radii = [];
  this.assembly_el = document.createElementNS(NS_URI, 'g');
  this.el = document.createElementNS(NS_URI, 'circle');
  
  this.el.classList.add('circle');
  setAttrs(this.el, {
    'cx': this.centre.x, 
    'cy':this.centre.y, 
    'r': this.radius
  });
  
  if(type === 'circumcircle') {
    for(var i = 0; i < parent.n; i++) {
      this.radii.push(new Segment(this.centre, parent.vertices[i]));
      this.radii[i].el.classList.add('circle__radius');
      radii_frag.appendChild(this.radii[i].el);
    }
  }
  if(type === 'incircle') {
    for(var i = 0; i < parent.n; i++) {
      b = parent.edges[i].midpoint();
      
      this.radii.push(new Segment(this.centre, b));
      
      this.radii[i].el.classList.add('circle__radius');
      b.el.classList.add('polygon__edge-midpoint');
      
      radii_frag.appendChild(this.radii[i].el);
      radii_frag.appendChild(b.el);
    }
  }
  
  this.assembly_el.appendChild(this.el);
  this.assembly_el.appendChild(radii_frag);
};

var Polygon = function(n, parent) {
  var parent = parent || frame, 
      radius_c = ((parent == frame)?1:random())*min(w, h)*.4, 
      central_angle = 2*PI/n, 
      start_angle = rand(central_angle), 
      radius_i = radius_c*cos(central_angle/2), 
      curr_angle, curr_x, curr_y, 
      frag_vertices = document.createElementNS(NS_URI, 'g'), 
      frag_edges = document.createElementNS(NS_URI, 'g'), 
      frag_circles = document.createElementNS(NS_URI, 'g');
  
  this.n = n;
  this.vertices = [];
  this.edges = [];
  this.el = document.createElementNS(NS_URI, 'g');
  
  this.el.classList.add('polygon');
  
  for(var i = 0; i < n; i++) {
    curr_angle = i*central_angle + start_angle;
    curr_x = round(radius_c*cos(curr_angle));
    curr_y = round(radius_c*sin(curr_angle));
    
    this.vertices.push(new Point(curr_x, curr_y));
    this.vertices[i].el.classList.add('polygon__vertex');
    this.vertices[i].el.setAttribute('data-i', i);
    frag_vertices.appendChild(this.vertices[i].el);
    
    if(i > 0) {
      this.edges.push(new Segment(this.vertices[i - 1], this.vertices[i]));
      this.edges[i - 1].el.classList.add('polygon__edge');
      frag_edges.appendChild(this.edges[i - 1].el);
      
      if(i === n - 1) {
        this.edges.push(new Segment(this.vertices[i], this.vertices[0]));
        this.edges[i].el.classList.add('polygon__edge');
        frag_edges.appendChild(this.edges[i].el);
      }
    }
  }
  
  this.circles = {
    'c': new Circle('circumcircle', radius_c, this), 
    'i': new Circle('incircle', radius_i, this)
  };
  
  this.o = this.circles.c.centre;
  
  frag_circles.appendChild(this.circles.c.assembly_el);
  this.circles.c.el.classList.add('polygon__circle');
  frag_circles.appendChild(this.circles.i.assembly_el);
  this.circles.i.el.classList.add('polygon__circle');
  this.o.el.classList.add('polygon__centre');
  
  this.el.appendChild(frag_edges);
  this.el.appendChild(frag_circles);
  this.el.appendChild(frag_vertices);
  this.el.appendChild(this.o.el);
  parent.appendChild(this.el);
  
};

var draw = function(n) {
  var poly = frame.querySelector('.polygon');
  
  if(poly) {
    frame.removeChild(poly);
  }
  
  poly = new Polygon(n, frame);
}

/* ========================= START IT ALL ========================= */
draw(n_slider_el.value);

/*
 * handle hitting ⇅ in text box 
 */
addEventListener('keyup', function(e) {}, false);

/*
 * handle moving slider thumb
 */
n_slider_el.addEventListener('change', function(e) {
  n_text_el.value = n_slider_el.value;
  draw(n_slider_el.value);
}, false);

/*
 * handle changing n text value
 */
n_text_el.addEventListener('blur', function(e) {
  n_slider_el.value = n_text_el.value;
  draw(n_slider_el.value);
}, false);
            
          
!
999px
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