Convert base64 for use with rect.fills imageHash

In my code.ts I have a JPEG image that’s been converted to base64 and I am attempting to use it as the imageHash value but am getting Invalid SHA1 hash error.

const img = '/9j/4AAQSkZJRgABAQAAAQABAAD/2wCEAA...

const rect = figma.createRectangle();
rect.fills = [{ type: 'IMAGE', scaleMode: 'FIT', imageHash: img }];

What conversion needs to happen to the base64 string in order to use it this way?

1 Like

The Plugin API says that images should be converted to Uint8Array.

Thank you. I realized I was trying to do the conversion inside code.ts but it needs to happen in ui.html. In ui.html I’m using a helper function to convert the base64 string.

  function _base64ToUint8Array(base64) {
    var binary_string = window.atob(base64);
    var len = binary_string.length;
    var bytes = new Uint8Array(len);
    for (var i = 0; i < len; i++) {
      bytes[i] = binary_string.charCodeAt(i);
    return new Uint8Array(bytes.buffer);

hey you have any idea about this error “ unhandled promise rejection: Error: in set_fills: Expected “fills.[0].imageHash” to have type string but got undefined instead”
im giving uint8array for imagehash

You should have passed a Uint8Array as an argument to the createImage method. This method will return an Image object in which you can get the value of the hash property and use this value to set the fill.

I want to note that in Figma there are methods for encoding/decoding Base64.

1 Like