add help text to channel backup QR code

electrum/gui/kivy/main_window.py

@@ -462,7 +462,7 @@ class ElectrumWindow(App):
         self.invoice_popup = InvoiceDialog('Invoice', data, key)
         self.invoice_popup.open()
 
-    def qr_dialog(self, title, data, show_text=False, text_for_clipboard=None):
+    def qr_dialog(self, title, data, show_text=False, text_for_clipboard=None, help_text=None):
         from .uix.dialogs.qr_dialog import QRDialog
         def on_qr_failure():
             popup.dismiss()
@@ -471,8 +471,11 @@ class ElectrumWindow(App):
                 msg += '\n' + _('Text copied to clipboard.')
                 self._clipboard.copy(text_for_clipboard)
             Clock.schedule_once(lambda dt: self.show_info(msg))
-        popup = QRDialog(title, data, show_text, failure_cb=on_qr_failure,
-                         text_for_clipboard=text_for_clipboard)
+        popup = QRDialog(
+            title, data, show_text,
+            failure_cb=on_qr_failure,
+            text_for_clipboard=text_for_clipboard,
+            help_text=help_text)
         popup.open()
 
     def scan_qr(self, on_complete):

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

@@ -373,7 +373,13 @@ class ChannelDetailsPopup(Popup):
 
     def export_backup(self):
         text = self.app.wallet.lnworker.export_channel_backup(self.chan.channel_id)
-        self.app.qr_dialog(_("Channel Backup " + self.chan.short_id_for_GUI()), 'channel_backup:'+text)
+        # TODO: some messages are duplicated between Kivy and Qt.
+        help_text = ' '.join([
+            _("Channel backups can be imported in another instance of the same wallet, by scanning this QR code."),
+            _("Please note that channel backups cannot be used to restore your channels."),
+            _("If you lose your wallet file, the only thing you can do with a backup is to request your channel to be closed, so that your funds will be sent on-chain."),
+        ])
+        self.app.qr_dialog(_("Channel Backup " + self.chan.short_id_for_GUI()), 'channel_backup:'+text, help_text=help_text)
 
     def force_close(self):
         Question(_('Force-close channel?'), self._force_close).open()

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

@@ -13,7 +13,7 @@ Builder.load_string('''
     title: ''
     data: ''
     shaded: False
-    show_text: False
+    help_text: ''
     AnchorLayout:
         anchor_x: 'center'
         BoxLayout:
@@ -29,7 +29,7 @@ Builder.load_string('''
                     touch = args[1]
                     if self.collide_point(*touch.pos): self.shaded = not self.shaded
             TopLabel:
-                text: root.data if root.show_text else ''
+                text: root.help_text
             Widget:
                 size_hint: 1, 0.2
             BoxLayout:
@@ -56,12 +56,12 @@ Builder.load_string('''
 
 class QRDialog(Factory.Popup):
     def __init__(self, title, data, show_text, *,
-                 failure_cb=None, text_for_clipboard=None):
+                 failure_cb=None, text_for_clipboard=None, help_text=None):
         Factory.Popup.__init__(self)
         self.app = App.get_running_app()
         self.title = title
         self.data = data
-        self.show_text = show_text
+        self.help_text = data if show_text else help_text
         self.failure_cb = failure_cb
         self.text_for_clipboard = text_for_clipboard if text_for_clipboard else data
 

electrum/gui/qt/channels_list.py

@@ -126,8 +126,13 @@ class ChannelsList(MyTreeView):
             self.lnbackups.remove_channel_backup(channel_id)
 
     def export_channel_backup(self, channel_id):
+        msg = ' '.join([
+            _("Channel backups can be imported in another instance of the same wallet, by scanning this QR code."),
+            _("Please note that channel backups cannot be used to restore your channels."),
+            _("If you lose your wallet file, the only thing you can do with a backup is to request your channel to be closed, so that your funds will be sent on-chain."),
+        ])
         data = self.lnworker.export_channel_backup(channel_id)
-        self.main_window.show_qrcode('channel_backup:' + data, 'channel backup')
+        self.main_window.show_qrcode('channel_backup:' + data, 'channel backup', help_text=msg)
 
     def request_force_close(self, channel_id):
         def task():

electrum/gui/qt/main_window.py

@@ -2372,10 +2372,10 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
         d = SeedDialog(self, seed, passphrase)
         d.exec_()
 
-    def show_qrcode(self, data, title = _("QR code"), parent=None):
+    def show_qrcode(self, data, title = _("QR code"), parent=None, help_text=None):
         if not data:
             return
-        d = QRDialog(data, parent or self, title)
+        d = QRDialog(data, parent or self, title, help_text=help_text)
         d.exec_()
 
     @protected

electrum/gui/qt/qrcodewidget.py

@@ -10,7 +10,7 @@ from PyQt5.QtWidgets import (
 
 from electrum.i18n import _
 
-from .util import WindowModalDialog, get_parent_main_window
+from .util import WindowModalDialog, get_parent_main_window, WWLabel
 
 
 class QRCodeWidget(QWidget):
@@ -93,17 +93,17 @@ class QRCodeWidget(QWidget):
 
 class QRDialog(WindowModalDialog):
 
-    def __init__(self, data, parent=None, title = "", show_text=False):
+    def __init__(self, data, parent=None, title = "", show_text=False, help_text=None):
         WindowModalDialog.__init__(self, parent, title)
 
         vbox = QVBoxLayout()
         qrw = QRCodeWidget(data)
         vbox.addWidget(qrw, 1)
-        if show_text:
-            text = QTextEdit()
-            text.setText(data)
-            text.setReadOnly(True)
-            vbox.addWidget(text)
+        help_text = data if show_text else help_text
+        if help_text:
+            text_label = WWLabel()
+            text_label.setText(help_text)
+            vbox.addWidget(text_label)
         hbox = QHBoxLayout()
         hbox.addStretch(1)