javascript - 命运之轮怎么画？

Question

我正在尝试使用本教程创建一个转盘游戏:

http://www.emanueleferonato.com/2015/07/31/create-a-wheel-of-fortune-for-your-html5-games-with-phaser-in-only-a-few-lines/

但是，本教程使用了轮子的图像，我想在 html5/js 中创建它。大概是这样的:

https://www.winkbingo.com/images/lp/301114/spin_the_wheel_image.png这是我到目前为止所拥有的:

var ctx = canvas.getContext("2d");
var end = 0;
var color = ['#F0F8FF','#FAEBD7','#00FFFF','#7FFFD4','#00FF00','#FF8C00'];
var labels = ['label1', 'label2','label3','label4','label5','label6'];
var slices = 6

for (var i = 0; i < slices; i++) {
ctx.fillStyle = color[i];
ctx.beginPath();
ctx.moveTo(canvas.width/2,canvas.height/2);
ctx.arc(canvas.width/2,canvas.height/2,canvas.height/2,end, ((1/slices)*Math.PI*2)+end ,false);
ctx.lineTo(canvas.width/2,canvas.height/2);
ctx.fill();
end += ((1/slices)*Math.PI*2)+end;
}

我希望能够通过更改变量切片(在 1-6 之间)来更改段数。我还想在顶部显示标签。然后我想使用这个 Canvas 而不是那个教程代码中的图像，这样轮子就会随着文本旋转。希望这不会造成混淆。任何人都知道如何做到这一点>我不介意使用任何图书馆等。

Answer 1

使用 JS Canvas 的命运之轮

const sectors = [
  {color:"#f82", label:"Stack"},
  {color:"#0bf", label:"10"},
  {color:"#fb0", label:"200"},
  {color:"#0fb", label:"50"},
  {color:"#b0f", label:"100"},
  {color:"#f0b", label:"5"},
  {color:"#bf0", label:"500"},
];

// Generate random float in range min-max:
const rand = (m, M) => Math.random() * (M - m) + m;

const tot = sectors.length;
const elSpin = document.querySelector("#spin");
const ctx = document.querySelector("#wheel").getContext`2d`;
const dia = ctx.canvas.width;
const rad = dia / 2;
const PI = Math.PI;
const TAU = 2 * PI;
const arc = TAU / sectors.length;
const friction = 0.991;  // 0.995=soft, 0.99=mid, 0.98=hard
const angVelMin = 0.002; // Below that number will be treated as a stop
let angVelMax = 0; // Random ang.vel. to acceletare to 
let angVel = 0;    // Current angular velocity
let ang = 0;       // Angle rotation in radians
let isSpinning = false;
let isAccelerating = false;

//* Get index of current sector */
const getIndex = () => Math.floor(tot - ang / TAU * tot) % tot;

//* Draw sectors and prizes texts to canvas */
const drawSector = (sector, i) => {
  const ang = arc * i;
  ctx.save();
  // COLOR
  ctx.beginPath();
  ctx.fillStyle = sector.color;
  ctx.moveTo(rad, rad);
  ctx.arc(rad, rad, rad, ang, ang + arc);
  ctx.lineTo(rad, rad);
  ctx.fill();
  // TEXT
  ctx.translate(rad, rad);
  ctx.rotate(ang + arc / 2);
  ctx.textAlign = "right";
  ctx.fillStyle = "#fff";
  ctx.font = "bold 30px sans-serif";
  ctx.fillText(sector.label, rad - 10, 10);
  //
  ctx.restore();
};

//* CSS rotate CANVAS Element */
const rotate = () => {
  const sector = sectors[getIndex()];
  ctx.canvas.style.transform = `rotate(${ang - PI / 2}rad)`;
  elSpin.textContent = !angVel ? "SPIN" : sector.label;
  elSpin.style.background = sector.color;
};

const frame = () => {

  if (!isSpinning) return;

  if (angVel >= angVelMax) isAccelerating = false;

  // Accelerate
  if (isAccelerating) {
    angVel ||= angVelMin; // Initial velocity kick
    angVel *= 1.06; // Accelerate
  }
  
  // Decelerate
  else {
    isAccelerating = false;
    angVel *= friction; // Decelerate by friction  

    // SPIN END:
    if (angVel < angVelMin) {
      isSpinning = false;
      angVel = 0; 
    }
  }

  ang += angVel; // Update angle
  ang %= TAU;    // Normalize angle
  rotate();      // CSS rotate!
};

const engine = () => {
  frame();
  requestAnimationFrame(engine)
};

elSpin.addEventListener("click", () => {
  if (isSpinning) return;
  isSpinning = true;
  isAccelerating = true;
  angVelMax = rand(0.25, 0.40);
});

// INIT!
sectors.forEach(drawSector);
rotate(); // Initial rotation
engine(); // Start engine!

#wheelOfFortune {
  display: inline-flex;
  position: relative;
  overflow: hidden;
}

#wheel {
  display: block;
}

#spin {
  font: 1.5rem/0 sans-serif;
  user-select: none;
  cursor: pointer;
  display: flex;
  justify-content: center;
  align-items: center;
  position: absolute;
  top: 50%;
  left: 50%;
  width: 30%;
  height: 30%;
  margin: -15%;
  background: #fff;
  color: #fff;
  box-shadow: 0 0 0 8px currentColor, 0 0px 15px 5px rgba(0, 0, 0, 0.6);
  border-radius: 50%;
  transition: 0.8s;
}

#spin::after {
  content: "";
  position: absolute;
  top: -17px;
  border: 10px solid transparent;
  border-bottom-color: currentColor;
  border-top: none;
}

<div id="wheelOfFortune">
  <canvas id="wheel" width="300" height="300"></canvas>
  <div id="spin">SPIN asd asd asd as dasd as dasd asd asd as d</div>
</div>