chore: establish learning module baseline

OpenMAIC/lib/export/svg2base64.ts

@@ -0,0 +1,58 @@
+// Convert SVG to base64 image. Reference: https://github.com/scriptex/svg64
+
+const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
+const PREFIX = 'data:image/svg+xml;base64,';
+
+const utf8Encode = (string: string) => {
+  string = string.replace(/\r\n/g, '\n');
+  let utftext = '';
+
+  for (let n = 0; n < string.length; n++) {
+    const c = string.charCodeAt(n);
+
+    if (c < 128) {
+      utftext += String.fromCharCode(c);
+    } else if (c > 127 && c < 2048) {
+      utftext += String.fromCharCode((c >> 6) | 192);
+      utftext += String.fromCharCode((c & 63) | 128);
+    } else {
+      utftext += String.fromCharCode((c >> 12) | 224);
+      utftext += String.fromCharCode(((c >> 6) & 63) | 128);
+      utftext += String.fromCharCode((c & 63) | 128);
+    }
+  }
+
+  return utftext;
+};
+
+const encode = (input: string) => {
+  let output = '';
+  let chr1, chr2, chr3, enc1, enc2, enc3, enc4;
+  let i = 0;
+  input = utf8Encode(input);
+  while (i < input.length) {
+    chr1 = input.charCodeAt(i++);
+    chr2 = input.charCodeAt(i++);
+    chr3 = input.charCodeAt(i++);
+    enc1 = chr1 >> 2;
+    enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
+    enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
+    enc4 = chr3 & 63;
+    if (isNaN(chr2)) enc3 = enc4 = 64;
+    else if (isNaN(chr3)) enc4 = 64;
+    output =
+      output +
+      characters.charAt(enc1) +
+      characters.charAt(enc2) +
+      characters.charAt(enc3) +
+      characters.charAt(enc4);
+  }
+  return output;
+};
+
+export const svg2Base64 = (element: Element) => {
+  const XMLS = new XMLSerializer();
+  const svg = XMLS.serializeToString(element);
+
+  return PREFIX + encode(svg);
+};