如何通过CropperJS获得裁剪图像的坐标？

Question

I am using cropper JS to crop my image. I am able to get width and height of my canvas, however, need to know co-ordinates (X and Y) of cropped image.

Here is my code-

(function () {


  //getting ratio
  function getImageRatio(sourceCanvas) {
    var canvas = document.createElement('canvas');
    var context = canvas.getContext('2d');
    var width = sourceCanvas.width;
    var height = sourceCanvas.height;



    canvas.width = width;
    canvas.height = height;


    context.beginPath();
    context.arc(width / 2, height / 2, Math.min(width, height) / 2, 0, 2 * Math.PI);
    context.strokeStyle = 'rgba(0,0,0,0)';
    context.stroke();
    context.clip();
    context.drawImage(sourceCanvas, 0, 0, width, height);

    return canvas;
  }




  window.addEventListener('DOMContentLoaded', function () {
    var image = document.getElementById('image');
    var button = document.getElementById('button');
    var result = document.getElementById('result');
    var croppable = false;
    var cropper = new Cropper(image, {
      aspectRatio: 1,
      viewMode: 1,
      built: function () {
        croppable = true;
      }
    });

    button.onclick = function () {
      var croppedCanvas;
      var roundedCanvas;
      var roundedImage;

      if (!croppable) {
        return;
      }

      // Crop
      croppedCanvas = cropper.getCroppedCanvas();


      console.log(getImageRatio(croppedCanvas));

    };

  });

})();

Any idea, how to get coordinate of cropped image, so that I can crop this image by PHP.

Answer 1

So, if i understand properly, you are looking for the method getData.

It will return these properties as the documentation says:

x: the offset left of the cropped area
y: the offset top of the cropped area
width: the width of the cropped area
height: the height of the cropped area
rotate: the rotated degrees of the image
scaleX: the scaling factor to apply on the abscissa of the image
scaleY: the scaling factor to apply on the ordinate of the image

Although, i suggest taking a look at this section of the doc: https://github.com/fengyuanchen/cropper#getcroppedcanvasoptions

Specifically at this part:

After then, you can display the canvas as an image directly, or use HTMLCanvasElement.toDataURL to get a Data URL, or use HTMLCanvasElement.toBlob to get a blob and upload it to server with FormData if the browser supports these APIs.

If you cannot use the toBlob method because some browser limitation (you can always add a polyfill), you can get the image using toDataUrl over the canvas (IE9+). And send it to the backend service already cropped. For this you are going to need to do something like this:

var formData = new FormData();
formData.append('image', canvas.toDataURL());

You can check the formData browser support in caniuse

Hope you find it helpful!