ltc payments

lib/ltc_qr.rb

@@ -0,0 +1,30 @@
+require 'rqrcode'
+
+# Renders a Litecoin payment QR as PNG bytes for embedding in the PDF.
+# Encodes a BIP21-style URI: litecoin:<address>?amount=<ltc>
+module LtcQr
+  module_function
+
+  # `amount` is a BigDecimal LTC amount or nil (address-only QR).
+  def uri(address, amount)
+    base = "litecoin:#{address}"
+    return base if amount.nil?
+    # Trim trailing zeros so the wallet shows a clean amount; keep up to 8 dp.
+    amt = amount.round(8).to_s('F').sub(/\.?0+$/, '')
+    "#{base}?amount=#{amt}"
+  end
+
+  # Returns PNG bytes (binary string), sized for a crisp ~120pt PDF placement.
+  def png(address, amount, size: 480)
+    data = uri(address, amount)
+    qr = RQRCode::QRCode.new(data, level: :m)
+    qr.as_png(
+      bit_depth:    1,
+      border_modules: 2,
+      color:        'black',
+      fill:         'white',
+      module_px_size: 6,
+      resize_exactly_to: size
+    ).to_s
+  end
+end