sd-webui-photopea-embed/javascript/data-utility-functions.js

/* Third party utility functions */

// Turn a base64 string into a blob. 
// From https://gist.github.com/gauravmehla/7a7dfd87dd7d1b13697b6e894426615f
function b64toBlob(b64Data, contentType, sliceSize) {
    var contentType = contentType || '';
    var sliceSize = sliceSize || 512;
    var byteCharacters = atob(b64Data);
    var byteArrays = [];
    for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
        var slice = byteCharacters.slice(offset, offset + sliceSize);
        var byteNumbers = new Array(slice.length);
        for (var i = 0; i < slice.length; i++) {
            byteNumbers[i] = slice.charCodeAt(i);
        }
        var byteArray = new Uint8Array(byteNumbers);
        byteArrays.push(byteArray);
    }
    return new Blob(byteArrays, { type: contentType });
}

// Turn an image into a b64 string.
// From https://stackoverflow.com/questions/6150289/how-can-i-convert-an-image-into-base64-string-using-javascript
function blobTob64(url, callback) {
    var xhr = new XMLHttpRequest();
    xhr.onload = function () {
        var reader = new FileReader();
        reader.onloadend = function () {
            callback(reader.result);
        }
        reader.readAsDataURL(xhr.response);
    };
    xhr.open('GET', url);
    xhr.responseType = 'blob';
    xhr.send();
}


/*
MIT LICENSE
Copyright 2011 Jon Leighton
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute, 
sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial
portions of the Software. 

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
// From: https://gist.github.com/jonleighton/958841
function base64ArrayBuffer(arrayBuffer) {
    var base64 = ''
    var encodings = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'

    var bytes = new Uint8Array(arrayBuffer)
    var byteLength = bytes.byteLength
    var byteRemainder = byteLength % 3
    var mainLength = byteLength - byteRemainder

    var a, b, c, d
    var chunk

    // Main loop deals with bytes in chunks of 3
    for (var i = 0; i < mainLength; i = i + 3) {
        // Combine the three bytes into a single integer
        chunk = (bytes[i] << 16) | (bytes[i + 1] << 8) | bytes[i + 2]

        // Use bitmasks to extract 6-bit segments from the triplet
        a = (chunk & 16515072) >> 18 // 16515072 = (2^6 - 1) << 18
        b = (chunk & 258048) >> 12 // 258048   = (2^6 - 1) << 12
        c = (chunk & 4032) >> 6 // 4032     = (2^6 - 1) << 6
        d = chunk & 63               // 63       = 2^6 - 1

        // Convert the raw binary segments to the appropriate ASCII encoding
        base64 += encodings[a] + encodings[b] + encodings[c] + encodings[d]
    }

    // Deal with the remaining bytes and padding
    if (byteRemainder == 1) {
        chunk = bytes[mainLength]

        a = (chunk & 252) >> 2 // 252 = (2^6 - 1) << 2

        // Set the 4 least significant bits to zero
        b = (chunk & 3) << 4 // 3   = 2^2 - 1

        base64 += encodings[a] + encodings[b] + '=='
    } else if (byteRemainder == 2) {
        chunk = (bytes[mainLength] << 8) | bytes[mainLength + 1]

        a = (chunk & 64512) >> 10 // 64512 = (2^6 - 1) << 10
        b = (chunk & 1008) >> 4 // 1008  = (2^6 - 1) << 4

        // Set the 2 least significant bits to zero
        c = (chunk & 15) << 2 // 15    = 2^4 - 1

        base64 += encodings[a] + encodings[b] + encodings[c] + '='
    }

    return base64
}