Please, talk to your developers to modify the following two lines of the code below.
Bitmap signatureBitmap = Bitmap.createScaledBitmap(signatureArea.getBitmap(), 450, 450, false);
printer.printImage(new ZebraImageAndroid(signatureBitmap), -1, -1, signatureBitmap.getWidth() , signatureBitmap.getHeight(), false);
It should fix the issue.
Regarding the Zebra utilities demo source code, we cannot provide this code, it is Zebra Proprietary.
However, your developers can reach out us to the following email for additional development support. ISV_NALA_Support@zebra.com