Documentation

<div class="card">
   <div class="card-body">
       <div class="row">
           <div class="col-md-6 text-center">
              <div class="croppy-round">
              <img src="../assets/images/plugins/01.jpg" alt="picture" class="img-fluid" id="round-crop" loading="lazy">
               </div>
               <button id="roundButton" class="btn btn-primary my-2">Crop</button>
            </div>
        <div class="col-md-6 text-center">
             <h5>Preview</h5>
             <div id="roundResult"></div>
             </div>
        </div>
   </div>
</div>

window.onload = function () {
function getRoundedCanvas(sourceCanvas) {
    const roundcanvas = document.createElement('canvas');
    const context = roundcanvas.getContext('2d');
    let width = sourceCanvas.width;
    let height = sourceCanvas.height;

    roundcanvas.width = width;
    roundcanvas.height = height;
    context.imageSmoothingEnabled = true;
    context.drawImage(sourceCanvas, 0, 0, width, height);
    context.globalCompositeOperation = 'destination-in';
    context.beginPath();
    context.arc(width / 2, height / 2, Math.min(width, height) / 2, 0, 2 * Math.PI, true);
    context.fill();
    return roundcanvas;
  }
    let roundImage = document.getElementById('round-crop');
    let roundButton = document.getElementById('roundButton');
    let roundResult = document.getElementById('roundResult');
    let roundcroppable = false;
    let roundCropper = new Cropper(roundImage, {
      aspectRatio: 1,
      viewMode: 1,
      ready: function () {
        roundcroppable = true;
      },
    });

    roundButton.onclick = function () {
      let croppedCanvas;
      let roundedCanvas;
      let roundedImage;

      if (!roundcroppable) {
        return;
      }

      // Crop
      croppedCanvas = roundCropper.getCroppedCanvas();

      // Round
      roundedCanvas = getRoundedCanvas(croppedCanvas);

      // Show
      roundedImage = document.createElement('img');
      roundedImage.src = roundedCanvas.toDataURL()
      roundedImage.classList = "img-fluid w-50";
      roundResult.innerHTML = '';
      roundResult.appendChild(roundedImage);
    };
};