PHP有人知道吗?

将接受的答案转换为PHP代码。帮助在服务器上生成弧。

function polarToCartesian($centerX, $centerY, $radius, $angleInDegrees) {
   $angleInRadians = ($angleInDegrees-90) * pi() / 180.0;

  return array(
    "x"=> $centerX + ($radius * cos($angleInRadians)),
    "y"=> $centerY + ($radius * sin($angleInRadians)),
  );
}

function describeArc($x, $y, $radius, $startAngle, $endAngle){

     $start = polarToCartesian($x, $y, $radius, $endAngle);
     $end = polarToCartesian($x, $y, $radius, $startAngle);

     $largeArcFlag = $endAngle - $startAngle <= 180 ? "0" : "1";

     $d = implode(" ", array(
        "M", $start["x"], $start["y"], 
        "A", $radius, $radius, 0, $largeArcFlag, 0, $end["x"], $end["y"]));

    return $d;       
}

<svg>
    <path fill="none" stroke="#446688" stroke-width="20" d="<?= describeArc(150, 150, 100, 0, 30) ?>" />
</svg>

对@opsb的回答稍加修改。我们不能用这种方法画一个完整的圆。如果我们给(0,360)它什么也画不出来。所以做了一点小小的修改来解决这个问题。显示有时达到100%的分数可能很有用。

function polarToCartesian(centerX, centerY, radius, angleInDegrees) {
  var angleInRadians = (angleInDegrees-90) * Math.PI / 180.0;

  return {
    x: centerX + (radius * Math.cos(angleInRadians)),
    y: centerY + (radius * Math.sin(angleInRadians))
  };
}

function describeArc(x, y, radius, startAngle, endAngle){

    var endAngleOriginal = endAngle;
    if(endAngleOriginal - startAngle === 360){
        endAngle = 359;
    }

    var start = polarToCartesian(x, y, radius, endAngle);
    var end = polarToCartesian(x, y, radius, startAngle);

    var arcSweep = endAngle - startAngle <= 180 ? "0" : "1";

    if(endAngleOriginal - startAngle === 360){
        var d = [
              "M", start.x, start.y, 
              "A", radius, radius, 0, arcSweep, 0, end.x, end.y, "z"
        ].join(" ");
    }
    else{
      var d = [
          "M", start.x, start.y, 
          "A", radius, radius, 0, arcSweep, 0, end.x, end.y
      ].join(" ");
    }

    return d;       
}

document.getElementById("arc1").setAttribute("d", describeArc(120, 120, 100, 0, 359));

基于所选答案的ReactJS组件:

import React from 'react';

const polarToCartesian = (centerX, centerY, radius, angleInDegrees) => {
    const angleInRadians = (angleInDegrees - 90) * Math.PI / 180.0;

    return {
        x: centerX + (radius * Math.cos(angleInRadians)),
        y: centerY + (radius * Math.sin(angleInRadians))
    };
};

const describeSlice = (x, y, radius, startAngle, endAngle) => {

    const start = polarToCartesian(x, y, radius, endAngle);
    const end = polarToCartesian(x, y, radius, startAngle);

    const largeArcFlag = endAngle - startAngle <= 180 ? "0" : "1";

    const d = [
        "M", 0, 0, start.x, start.y,
        "A", radius, radius, 0, largeArcFlag, 0, end.x, end.y
    ].join(" ");

    return d;
};

const path = (degrees = 90, radius = 10) => {
    return describeSlice(0, 0, radius, 0, degrees) + 'Z';
};

export const Arc = (props) => <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 300 300">
    <g transform="translate(150,150)" stroke="#000" strokeWidth="2">
        <path d={path(props.degrees, props.radius)} fill="#333"/>
    </g>

</svg>;

export default Arc;

我稍微修改了opsb的答案，并在圆形扇区的支持填充中进行了修改。 http://codepen.io/anon/pen/AkoGx

JS

function polarToCartesian(centerX, centerY, radius, angleInDegrees) {
  var angleInRadians = (angleInDegrees-90) * Math.PI / 180.0;

  return {
    x: centerX + (radius * Math.cos(angleInRadians)),
    y: centerY + (radius * Math.sin(angleInRadians))
  };
}

function describeArc(x, y, radius, startAngle, endAngle){

    var start = polarToCartesian(x, y, radius, endAngle);
    var end = polarToCartesian(x, y, radius, startAngle);

    var arcSweep = endAngle - startAngle <= 180 ? "0" : "1";

    var d = [
        "M", start.x, start.y, 
        "A", radius, radius, 0, arcSweep, 0, end.x, end.y,
        "L", x,y,
        "L", start.x, start.y
    ].join(" ");

    return d;       
}

document.getElementById("arc1").setAttribute("d", describeArc(200, 400, 100, 0, 220));

HTML

<svg>
  <path id="arc1" fill="orange" stroke="#446688" stroke-width="0" />
</svg>

你可以使用我为上面的答案做的JSFiddle代码:

https://jsfiddle.net/tyw6nfee/

你所需要做的就是改变最后一行console.log代码，并给它自己的参数:

  console.log(describeArc(255,255,220,30,180));
  console.log(describeArc(CenterX,CenterY,Radius,startAngle,EndAngle))

对于寻求答案的人(我也是)，如果不是必须使用arc，绘制部分圆的一个更简单的解决方案是使用SVG的stroke-dasharray <circle>。

将虚线数组分为两个元素，并将其范围缩放到所需的角度。起始角度可以使用冲程-达霍夫集进行调整。

看不见一个余弦。

完整的例子和解释: https://codepen.io/mjurczyk/pen/wvBKOvP