html - HTML5 / CSS3 部分枠付き円

Question

HTML5/CSS3のみで、円の途中までしか境界線がない円を作ることはできますか? そうでない場合、この効果を達成するためにどのようなテクニックを使用できますか? 私は純粋な DOM 要素を使用することを好みますが、必要に応じて、キャンバスに描画したり、SVG をスピンアップしたりできます。

Answer 1

はい、可能です - これを見てください：

デモ

.circle {
  position: relative;
  margin: 7em auto;
  width: 16em;
  height: 16em;
  border-radius: 50%;
  background: lightblue;
}

.arc {
  overflow: hidden;
  position: absolute;
  /* make sure top & left values are - the width of the border */
  /* the bottom right corner is the centre of the parent circle */
  top: -1em;
  right: 50%;
  bottom: 50%;
  left: -1em;
  /* the transform origin is the bottom right corner */
  transform-origin: 100% 100%;
  /* rotate by any angle */
  /* the skew angle is 90deg - the angle you want for the arc */
  transform: rotate(45deg) skewX(30deg);
}

.arc:before {
  box-sizing: border-box;
  display: block;
  border: solid 1em navy;
  width: 200%;
  height: 200%;
  border-radius: 50%;
  transform: skewX(-30deg);
  content: '';
}

<div class='circle'>
  <div class='arc'></div>
</div>

Answer 2

それが可能だ。

• 2 つの円を重ねて 2 つ描きborder-radiusます。
• transparentを変更して、両方の円の 1 つまたは複数の円弧を作成しborder-colorます。
• を使用transformして 2 番目の円を回転すると、必要なサイズの円弧が得られます。

これがデモです：http://jsfiddle.net/kJXwZ/2/

.wrapper {
  position: relative;
  margin: 20px;
}

.arc {
  position: absolute;
  top: 0;
  left: 0;
  width: 100px;
  height: 100px;
  border-radius: 100%;
  border: 1px solid;
}

.arc_start {
  border-color: transparent red red red;
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
}

.arc_end {
  border-color: red red red transparent;
  -webkit-transform: rotate(75deg);
  -moz-transform: rotate(75deg);
  -ms-transform: rotate(75deg);
  -o-transform: rotate(75deg);
  transform: rotate(75deg);
}

<div class="wrapper">
  <div class="arc arc_start"></div>
  <div class="arc arc_end"></div>
</div>

Answer 3

これはJavaScriptも使用するため、元の要件から外れています:(
..しかし、配信します

>>デモがあります<<こちら

@gkondありがとう、私はあなたの答えからこれを導き出しました

// create a circle using HTML5 / CSS3 / JS which has a border that only goes part-way around
// the circle .. and which can be smoothly animated from 0% to 100% around the circle

// this solution allows for animation and still results in relatively clean code
// we use four quarter-circles, all hidden away behind a white square to start with..
// all four are rotated out clockwise, and each quarter will stop at it's own maximum:
// q1 at 25%, q2 at 50% .. etc. once we reach a value at or over 25%, all four quarters
// should be out from behind the white square, and we can hide it.. it needs to be
// hidden if we display a value over 75%, or else q4 will end up going in behind it again
// .. also, since the top border will usually sit between the angles of  -45 to 45, we
// rotate everything by an extra -45 to make it all line up with the top nicely

var fromHidden = -90;

// utility function to align 0 degrees with top
// takes degrees and returns degrees - 45
function topAlign(degrees) {
  return degrees - 45
};

// utility function to rotate a jQuery element
// takes element and the degree of rotation (from the top) 
function rotate(el, degrees) {
  var degrees = topAlign(degrees || 0);
  el.css(
    'transform', 'rotate(' + degrees + 'deg)',
    '-webkit-transform', 'rotate(' + degrees + 'deg)',
    '-moz-transform', 'rotate(' + degrees + 'deg)',
    '-ms-transform', 'rotate(' + degrees + 'deg)',
    '-o-transform', 'rotate(' + degrees + 'deg)'
  )
}

// function to draw semi-circle
// takes a jQuery element and a value (between 0 and 1)
// element must contain four .arc_q elements
function circle(el, normalisedValue) {
  var degrees = normalisedValue * 360; // turn normalised value into degrees
  var counter = 1; // keeps track of which quarter we're working with
  el.find('.arc_q').each(function() { // loop over quarters..
    var angle = Math.min(counter * 90, degrees); // limit angle to maximum allowed for this quarter
    rotate($(this), fromHidden + angle); // rotate from the hiding place
    counter++; // track which quarter we'll be working with in next pass over loop
  });
  if (degrees > 90) { // hide the cover-up square soon as we can
    el.find('.arc_cover').css('display', 'none');
  }
}

// uses the the circle function to 'animate' drawing of the semi-circle
// incrementally increses the value passed by 0.01 up to the value required
function animate(el, normalisedValue, current) {
  var current = current || 0;
  circle(el, current);
  if (current < normalisedValue) {
    current += 0.01;
    setTimeout(function() {
      animate(el, normalisedValue, current);
    }, 1);
  }
}

// kick things off ..
animate($('.circle'), 0.69);

.circle {
  position: relative;
  margin: 20px;
  width: 120px;
  height: 120px;
}

.arc_q {
  position: absolute;
  top: 0;
  left: 0;
  width: 100px;
  height: 100px;
  border-radius: 50%;
  border: 10px solid;
  border-color: transparent green transparent transparent;
  transform: rotate(-45deg);
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -ms-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
}

.arc_cover {
  position: absolute;
  top: 0;
  left: 0;
  width: 60px;
  height: 60px;
  background-color: white;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="circle">
  <div class="arc_q"></div>
  <div class="arc_q"></div>
  <div class="arc_q"></div>
  <div class="arc_q"></div>
  <div class="arc_cover"></div>
</div>

Answer 4

円錐勾配解 (任意の角度で機能):

:root{
--degree:80deg;
--color:red;
}

.a{
  height:200px;
  width:200px;
border-radius:50%;
background: conic-gradient(
     var(--color) var(--degree), transparent calc(var(--degree) + 0.5deg) 100%);

}

.b{
  height:84%;
  width:84%;
  top:8%;
  left:8%;
  position:relative;
  border-radius:50%;
  background:#D3D3D3;
}

<div class ="a">
    <div class="b">
</div>

Answer 5

これをアニメーション化する最も簡単な方法は、css キーフレームを使用することです。

http://jsfiddle.net/8SUPX/644/

/**
 * HTML5 / CSS3 Circle with Partial Border
 * http://stackoverflow.com/q/13059190/1397351
 */
* { margin: 0; padding: 0; }
.circle {
	position: relative;
	margin: 6em auto;
	width: 12em; height: 12em;
	border-radius: 50%;
	background: transparent;
	border:20px solid #efefef;
	border-top-color: #efefef;
    border-right-color: #efefef;
    border-bottom-color: #efefef;
    border-left-color: #efefef;
    
    -webkit-transition:.5s;-moz-transition:.5s;transition:.5s;
}
.circle:hover{
      -webkit-animation:  animix 0.5s 1;
      -webkit-animation-fill-mode: forwards;
      -moz-animation:  animix 0.5s 1;
      -moz-animation-fill-mode: forwards;
      animation:  animix 0.5s 1;
      animation-fill-mode: forwards;
}



  //Animate
   @-webkit-keyframes animix {
    0% { 
      border-top-color: transparent;
      border-right-color: transparent;
      border-bottom-color: transparent;
      border-left-color: transparent;
    }
     25% { 
       border-top-color: red;
       border-right-color: transparent;
       border-bottom-color: transparent;
       border-left-color: transparent;
     }
     50% { 
       border-top-color: red;
       border-right-color: red;
       border-bottom-color: transparent;
       border-left-color: transparent;
     }
     75% { 
       border-top-color: red;
       border-right-color: red;
       border-bottom-color: red;
       border-left-color: transparent;
     }
     100% { 
       border-top-color: red;
       border-right-color: red;
       border-bottom-color: red;
       border-left-color: red;
     }
   }
   
      @keyframes animix {
    0% { 
      border-top-color: transparent;
      border-right-color: transparent;
      border-bottom-color: transparent;
      border-left-color: transparent;
    }
     25% { 
       border-top-color: red;
       border-right-color: transparent;
       border-bottom-color: transparent;
       border-left-color: transparent;
     }
     50% { 
       border-top-color: red;
       border-right-color: red;
       border-bottom-color: transparent;
       border-left-color: transparent;
     }
     75% { 
       border-top-color: red;
       border-right-color: red;
       border-bottom-color: red;
       border-left-color: transparent;
     }
     100% { 
       border-top-color: red;
       border-right-color: red;
       border-bottom-color: red;
       border-left-color: red;
     }
   }

<div class="circle"> </div>