Added basic barcode generation

ref #13

package.json

@@ -41,6 +41,7 @@
   "dependencies": {
     "@odit/class-validator-jsonschema": "^2.1.1",
     "axios": "^0.21.1",
+    "bwip-js": "^2.0.12",
     "cheerio": "^1.0.0-rc.5",
     "class-transformer": "0.3.1",
     "class-validator": "^0.13.1",

src/PdfCreator.ts

@@ -179,6 +179,25 @@ export class PdfCreator {
         return <Buffer>(await mergedPdf.save());
     }
 
+    /**
+     * A simple barcode generation function using default params suitable for usage in pdfs.
+     * Generates the barcodes as base64-encoded png.
+     * @param type Barcode type according to this list: https://github.com/metafloor/bwip-js/wiki/BWIPP-Barcode-Types
+     * @param content Barcode content/text - please remember that some formats only support certain input types.
+     * @returns Barcode image as base64 encoded png string.
+     */
+    public async generateBarcode(type: string, content: string): Promise<String> {
+        let barcode: Buffer = await bwipjs.toBuffer({
+            bcid: type,
+            text: content,
+            scale: 3,
+            height: 10,
+            includetext: true,
+            textxalign: 'center',
+        });
+        return `data:$image/png;base64,${barcode.toString('base64')}`;
+    }
+
     /**
      * Generates a new dummy runner with halfspaces for all strings.
      * Can be used to generate empty sponsoring contracts.