Can the DOMString data returned from HTMLCanvasElement.toDataURL() or canvas.toBlob() be reused?

Question

Can the DOMString data returned from HTMLCanvasElement.toDataURL() or canvas.toBlob() be reused?

As I work on setting up an image Cropper, I am obtaining the width and height, X and Y coordinates of the cropped details. With this data, I am able to create a preview image using canvas elements. However, my query is whether it is feasible to save the data returned from HTMLCanvasElement.toDataURL() or canvas.toBlob() so that it can be reused across different devices and browsers?

If interested, you can refer to the following link (which utilizes the canvas.toBlob() method): https://codesandbox.io/s/72py4jlll6

html css reactjs canvas frontend

Answer 1

Answer №1

Feel free to try out these code snippets:

if (!HTMLCanvasElement.prototype.toBlob) {
 Object.defineProperty(HTMLCanvasElement.prototype, 'toBlob', {
  value: function (callback, type, quality) {

    var binStr = atob( this.toDataURL(type, quality).split(',')[1] ),
        len = binStr.length,
        arr = new Uint8Array(len);

    for (var i=0; i<len; i++ ) {
     arr[i] = binStr.charCodeAt(i);
    }

    callback( new Blob( [arr], {type: type || 'image/png'} ) );
  }
 });
}

Feel free to modify the code as needed. Let me know your thoughts.

Answer 2

Feel free to try out these code snippets:

if (!HTMLCanvasElement.prototype.toBlob) {
 Object.defineProperty(HTMLCanvasElement.prototype, 'toBlob', {
  value: function (callback, type, quality) {

    var binStr = atob( this.toDataURL(type, quality).split(',')[1] ),
        len = binStr.length,
        arr = new Uint8Array(len);

    for (var i=0; i<len; i++ ) {
     arr[i] = binStr.charCodeAt(i);
    }

    callback( new Blob( [arr], {type: type || 'image/png'} ) );
  }
 });
}

Feel free to modify the code as needed. Let me know your thoughts.

Answer 3

Answer №2

One method involves converting a Blob into a base64 string and then storing it on the server side.

This allows for serving the media to various users or browsers at a later time.

To accomplish this, follow these steps:

let reader = new FileReader();
reader.readAsDataURL(blob); // converts the blob to base64 and triggers onload

reader.onload = function() {
  data = reader.result; // data url as base 64 encoded string.
};

Decoding this string will yield the binary PNG data.

Answer 4

One method involves converting a Blob into a base64 string and then storing it on the server side.

This allows for serving the media to various users or browsers at a later time.

To accomplish this, follow these steps:

let reader = new FileReader();
reader.readAsDataURL(blob); // converts the blob to base64 and triggers onload

reader.onload = function() {
  data = reader.result; // data url as base 64 encoded string.
};

Decoding this string will yield the binary PNG data.

Can the DOMString data returned from HTMLCanvasElement.toDataURL() or canvas.toBlob() be reused?

Answer №1

Answer №2

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