receive requests: encode lightning invoices as uppercase -> smaller QRs

By encoding bolt11 invoices as uppercase text in QR codes,
we can use the alphanumeric mode, which results in non-negligibly smaller QR codes.

electrum/gui/kivy/main_window.py

@@ -431,9 +431,8 @@ class ElectrumWindow(App):
     def show_request(self, is_lightning, key):
         from .uix.dialogs.request_dialog import RequestDialog
         request = self.wallet.get_request(key)
-        status = request['status']
         data = request['invoice'] if is_lightning else request['URI']
-        self.request_popup = RequestDialog('Request', data, key)
+        self.request_popup = RequestDialog('Request', data, key, is_lightning=is_lightning)
         self.request_popup.set_status(request['status'])
         self.request_popup.open()
 

electrum/gui/kivy/uix/dialogs/addresses.py

@@ -1,3 +1,5 @@
+from typing import TYPE_CHECKING
+
 from kivy.app import App
 from kivy.factory import Factory
 from kivy.properties import ObjectProperty
@@ -7,6 +9,10 @@ from kivy.uix.popup import Popup
 
 from electrum.gui.kivy.i18n import _
 
+if TYPE_CHECKING:
+    from ...main_window import ElectrumWindow
+
+
 Builder.load_string('''
 <AddressLabel@Label>
     text_size: self.width, None
@@ -184,7 +190,7 @@ class AddressesDialog(Factory.Popup):
 
     def __init__(self, app):
         Factory.Popup.__init__(self)
-        self.app = app
+        self.app = app  # type: ElectrumWindow
 
     def get_card(self, addr, balance, is_used, label):
         ci = {}

electrum/gui/kivy/uix/dialogs/request_dialog.py

@@ -66,16 +66,22 @@ Builder.load_string('''
 
 class RequestDialog(Factory.Popup):
 
-    def __init__(self, title, data, key):
+    def __init__(self, title, data, key, *, is_lightning=False):
         self.status = PR_UNKNOWN
         Factory.Popup.__init__(self)
         self.app = App.get_running_app()
         self.title = title
         self.data = data
         self.key = key
+        self.is_lightning = is_lightning
 
     def on_open(self):
-        self.ids.qr.set_data(self.data)
+        data = self.data
+        if self.is_lightning:
+            # encode lightning invoices as uppercase so QR encoding can use
+            # alphanumeric mode; resulting in smaller QR codes
+            data = data.upper()
+        self.ids.qr.set_data(data)
 
     def set_status(self, status):
         self.status = status

electrum/gui/qt/main_window.py

@@ -60,7 +60,7 @@ from electrum.util import (format_time, format_satoshis, format_fee_satoshis,
                            decimal_point_to_base_unit_name,
                            UnknownBaseUnit, DECIMAL_POINT_DEFAULT, UserFacingException,
                            get_new_wallet_name, send_exception_to_crash_reporter,
-                           InvalidBitcoinURI)
+                           InvalidBitcoinURI, maybe_extract_bolt11_invoice)
 from electrum.util import PR_TYPE_ONCHAIN, PR_TYPE_LN
 from electrum.transaction import (Transaction, PartialTxInput,
                                   PartialTransaction, PartialTxOutput)
@@ -1171,6 +1171,10 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
 
     def update_receive_qr(self):
         uri = str(self.receive_address_e.text())
+        if maybe_extract_bolt11_invoice(uri):
+            # encode lightning invoices as uppercase so QR encoding can use
+            # alphanumeric mode; resulting in smaller QR codes
+            uri = uri.upper()
         self.receive_qr.setData(uri)
         if self.qr_window and self.qr_window.isVisible():
             self.qr_window.qrw.setData(uri)