QR code fixes

New classes ScanQRTextEdit and ShowQRTextEdit.
Reason: dependencies on zbar availability and issues with the QRTextEdit constructor.
- ScanQRTextEdit needs access to the config (fetch camera). It needs to load
the zbar processor properly before trying to scan. Keeping a reference to
the processor in qrscaner fixes the crashes on windows.
- ShowQRTextEdit should not have access to scan_qr().
- no need to setReadOnly anymore. It is clear from the class name.

Show master pub keys now has a Combobox if multiple accounts are
available.

gui/qt/installwizard.py

@@ -128,7 +128,7 @@ class InstallWizard(QDialog):
     def enter_seed_dialog(self, msg, sid, func=None):
         if func is None:
             func = self.is_any
-        vbox, seed_e = seed_dialog.enter_seed_box(msg, sid)
+        vbox, seed_e = seed_dialog.enter_seed_box(msg, self, sid)
         vbox.addStretch(1)
         hbox, button = ok_cancel_buttons2(self, _('Next'))
         vbox.addLayout(hbox)

gui/qt/main_window.py

@@ -45,7 +45,7 @@ from electrum import Imported_Wallet
 from amountedit import AmountEdit, BTCAmountEdit, MyLineEdit
 from network_dialog import NetworkDialog
 from qrcodewidget import QRCodeWidget, QRDialog
-from qrtextedit import QRTextEdit
+from qrtextedit import ScanQRTextEdit, ShowQRTextEdit
 
 from decimal import Decimal
 
@@ -1828,15 +1828,36 @@ class ElectrumWindow(QMainWindow):
 
         main_layout = QGridLayout()
         mpk_dict = self.wallet.get_master_public_keys()
-        i = 0
+        # filter out the empty keys (PendingAccount)
-        for key, value in mpk_dict.items():
+        mpk_dict = {acc:mpk for acc,mpk in mpk_dict.items() if mpk}
-            main_layout.addWidget(QLabel(key), i, 0)
+
-            mpk_text = QRTextEdit()
+        # only show the combobox in case multiple accounts are available
-            mpk_text.setReadOnly(True)
+        if len(mpk_dict) > 1:
+            main_layout.addWidget(QLabel(_("Select Account")), 0, 0)
+
+            combobox = QComboBox()
+            for name in mpk_dict:
+                combobox.addItem(name)
+            combobox.setCurrentIndex(0)
+            main_layout.addWidget(combobox, 1, 0)
+
+            account = unicode(combobox.currentText())
+            mpk_text = ShowQRTextEdit(text=mpk_dict[account])
+            mpk_text.setMaximumHeight(170)
+            mpk_text.selectAll()    # for easy copying
+            main_layout.addWidget(mpk_text, 2, 0)
+
+            def show_mpk(account):
+                mpk = mpk_dict.get(unicode(account), "")
+                mpk_text.setText(mpk)
+
+            combobox.currentIndexChanged[str].connect(lambda acc: show_mpk(acc))
+        elif len(mpk_dict) == 1:
+            mpk = mpk_dict.values()[0]
+            mpk_text = ShowQRTextEdit(text=mpk)
             mpk_text.setMaximumHeight(170)
-            mpk_text.setText(value)
+            mpk_text.selectAll()    # for easy copying
-            main_layout.addWidget(mpk_text, i + 1, 0)
+            main_layout.addWidget(mpk_text, 2, 0)
-            i += 2
 
         vbox = QVBoxLayout()
         vbox.addLayout(main_layout)
@@ -1845,7 +1866,6 @@ class ElectrumWindow(QMainWindow):
         dialog.setLayout(vbox)
         dialog.exec_()
 
-
     @protected
     def show_seed_dialog(self, password):
         if not self.wallet.has_seed():
@@ -1900,9 +1920,7 @@ class ElectrumWindow(QMainWindow):
         vbox = QVBoxLayout()
         vbox.addWidget( QLabel(_("Address") + ': ' + address))
         vbox.addWidget( QLabel(_("Public key") + ':'))
-        keys = QRTextEdit()
+        keys = ShowQRTextEdit(text='\n'.join(pubkey_list))
-        keys.setReadOnly(True)
-        keys.setText('\n'.join(pubkey_list))
         vbox.addWidget(keys)
         vbox.addLayout(close_button(d))
         d.setLayout(vbox)
@@ -1924,9 +1942,7 @@ class ElectrumWindow(QMainWindow):
         vbox = QVBoxLayout()
         vbox.addWidget( QLabel(_("Address") + ': ' + address))
         vbox.addWidget( QLabel(_("Private key") + ':'))
-        keys = QRTextEdit()
+        keys = ShowQRTextEdit(text='\n'.join(pk_list))
-        keys.setReadOnly(True)
-        keys.setText('\n'.join(pk_list))
         vbox.addWidget(keys)
         vbox.addLayout(close_button(d))
         d.setLayout(vbox)
@@ -2128,6 +2144,12 @@ class ElectrumWindow(QMainWindow):
 
     def read_tx_from_qrcode(self):
         from electrum import qrscanner
+        if qrscanner.proc is None:
+            try:
+                qrscanner.init(self.config)
+            except Exception, e:
+                QMessageBox.warning(self, _('Error'), _(e), _('OK'))
+                return
         try:
             data = qrscanner.scan_qr(self.config)
         except BaseException, e:
@@ -2135,12 +2157,14 @@ class ElectrumWindow(QMainWindow):
             return
         if not data:
             return
+        # if the user scanned a bitcoin URI
+        if data.startswith("bitcoin:"):
+            self.pay_from_URI(data)
+            return
+        # else if the user scanned an offline signed tx
         # transactions are binary, but qrcode seems to return utf8...
         z = data.decode('utf8')
-        s = ''
+        data = ''.join(chr(ord(b)) for b in z).encode('hex')
-        for b in z:
-            s += chr(ord(b))
-        data = s.encode('hex')
         tx = self.tx_from_text(data)
         if not tx:
             return

gui/qt/paytoedit.py

@@ -18,7 +18,7 @@
 
 from PyQt4.QtCore import *
 from PyQt4.QtGui import *
-from qrtextedit import QRTextEdit
+from qrtextedit import ScanQRTextEdit
 
 import re
 from decimal import Decimal
@@ -30,11 +30,9 @@ RE_ALIAS = '(.*?)\s*\<([1-9A-HJ-NP-Za-km-z]{26,})\>'
 frozen_style = "QWidget { background-color:none; border:none;}"
 normal_style = "QPlainTextEdit { }"
 
-class PayToEdit(QRTextEdit):
+class PayToEdit(ScanQRTextEdit):
-
     def __init__(self, win):
-        QRTextEdit.__init__(self)
+        super(PayToEdit,self).__init__(win=win)
-        self.win = win
         self.amount_edit = win.amount_e
         self.document().contentsChanged.connect(self.update_size)
         self.heightMin = 0
@@ -235,3 +233,10 @@ class PayToEdit(QRTextEdit):
         cr = self.cursorRect()
         cr.setWidth(self.c.popup().sizeHintForColumn(0) + self.c.popup().verticalScrollBar().sizeHint().width())
         self.c.complete(cr)
+
+
+    def qr_input(self):
+        data = super(PayToEdit,self).qr_input()
+        if data.startswith("bitcoin:"):
+            self.scan_f(data)
+            # TODO: update fee

gui/qt/qrcodewidget.py

@@ -114,7 +114,7 @@ class QRDialog(QDialog):
 
             def copy_to_clipboard():
                 bmp.save_qrcode(qrw.qr, filename)
-                self.parent().app.clipboard().setImage(QImage(filename))
+                QApplication.clipboard().setImage(QImage(filename))
                 QMessageBox.information(None, _('Message'), _("QR code saved to clipboard"), _('OK'))
 
             b = QPushButton(_("Copy"))

gui/qt/qrtextedit.py

@@ -3,14 +3,13 @@ from PyQt4.QtGui import *
 from PyQt4.QtCore import *
 
 class QRTextEdit(QPlainTextEdit):
-
+    """Abstract class for QR-code related TextEdits. Do not use directly."""
     def __init__(self, text=None):
-        QPlainTextEdit.__init__(self, text)
+        super(QRTextEdit, self).__init__(text)
         self.button = QToolButton(self)
         self.button.setIcon(QIcon(":icons/qrcode.png"))
         self.button.setStyleSheet("QToolButton { border: none; padding: 0px; }")
         self.button.setVisible(True)
-        self.button.clicked.connect(lambda: self.qr_show() if self.isReadOnly() else self.qr_input())
         self.setText = self.setPlainText
 
     def resizeEvent(self, e):
@@ -21,13 +20,11 @@ class QRTextEdit(QPlainTextEdit):
                          (self.rect().bottom() - frameWidth - sz.height()))
         return o
 
-    def contextMenuEvent(self, e):
+class ShowQRTextEdit(QRTextEdit):
-        m = self.createStandardContextMenu()
+    def __init__(self, text=None):
-        if self.isReadOnly():
+        super(ShowQRTextEdit, self).__init__(text)
-            m.addAction(_("Show as QR code"), self.qr_show)
+        self.setReadOnly(1)
-        else:
+        self.button.clicked.connect(self.qr_show)
-            m.addAction(_("Read QR code"), self.qr_input)
-        m.exec_(e.globalPos())
 
     def qr_show(self):
         from qrcodewidget import QRDialog
@@ -37,13 +34,42 @@ class QRTextEdit(QPlainTextEdit):
             s = unicode(self.toPlainText())
         QRDialog(s).exec_()
 
+    def contextMenuEvent(self, e):
+        m = self.createStandardContextMenu()
+        m.addAction(_("Show as QR code"), self.qr_show)
+        m.exec_(e.globalPos())
+
+
+class ScanQRTextEdit(QRTextEdit):
+    def __init__(self, win, text=""):
+        super(ScanQRTextEdit,self).__init__(text)
+        self.setReadOnly(0)
+        self.win = win
+        assert win, "You must pass a window with access to the config to ScanQRTextEdit constructor."
+        if win:
+            assert hasattr(win,"config"), "You must pass a window with access to the config to ScanQRTextEdit constructor."
+        self.button.clicked.connect(self.qr_input)
+
+
     def qr_input(self):
         from electrum import qrscanner
+        if qrscanner.proc is None:
+            try:
+                qrscanner.init(self.win.config)
+            except Exception, e:
+                QMessageBox.warning(self, _('Error'), _(e), _('OK'))
+                return
         try:
             data = qrscanner.scan_qr(self.win.config)
         except BaseException, e:
-            QMessageBox.warning(self.win, _('Error'), _(e), _('OK'))
+            QMessageBox.warning(self, _('Error'), _(e), _('OK'))
             return
         if type(data) != str:
             return
         self.setText(data)
+        return data
+
+    def contextMenuEvent(self, e):
+        m = self.createStandardContextMenu()
+        m.addAction(_("Read QR code"), self.qr_input)
+        m.exec_(e.globalPos())

gui/qt/seed_dialog.py

@@ -23,7 +23,7 @@ from electrum.i18n import _
 from electrum import mnemonic
 from qrcodewidget import QRCodeWidget, QRDialog
 from util import close_button
-from qrtextedit import QRTextEdit
+from qrtextedit import ShowQRTextEdit, ScanQRTextEdit
 
 class SeedDialog(QDialog):
     def __init__(self, parent, seed, imported_keys):
@@ -72,15 +72,13 @@ def show_seed_box(seed, sid=None):
                + _("If you ever need to recover your wallet from seed, you will need both this seed and your cold seed.") + " " \
 
     label1 = QLabel(msg+ ":")
-    seed_text = QRTextEdit(seed)
+    seed_text = ShowQRTextEdit(text=seed)
-    seed_text.setReadOnly(True)
     seed_text.setMaximumHeight(130)
 
     label2 = QLabel(msg2)
     label2.setWordWrap(True)
 
     logo = QLabel()
-
     logo.setPixmap(QPixmap(icon_filename(sid)).scaledToWidth(56))
     logo.setMaximumWidth(60)
 
@@ -96,8 +94,7 @@ def show_seed_box(seed, sid=None):
     return vbox
 
 
-def enter_seed_box(msg, sid=None):
+def enter_seed_box(msg, window, sid=None):
-
     vbox = QVBoxLayout()
     logo = QLabel()
     logo.setPixmap(QPixmap(icon_filename(sid)).scaledToWidth(56))
@@ -106,7 +103,7 @@ def enter_seed_box(msg, sid=None):
     label = QLabel(msg)
     label.setWordWrap(True)
 
-    seed_e = QRTextEdit()
+    seed_e = ScanQRTextEdit(win=window)
     seed_e.setMaximumHeight(100)
     seed_e.setTabChangesFocus(True)
 

gui/qt/util.py

@@ -137,7 +137,7 @@ def line_dialog(parent, title, label, ok_label, default=None):
         return unicode(txt.text())
 
 def text_dialog(parent, title, label, ok_label, default=None):
-    from qrtextedit import QRTextEdit
+    from qrtextedit import ScanQRTextEdit
     dialog = QDialog(parent)
     dialog.setMinimumWidth(500)
     dialog.setWindowTitle(title)
@@ -145,7 +145,7 @@ def text_dialog(parent, title, label, ok_label, default=None):
     l = QVBoxLayout()
     dialog.setLayout(l)
     l.addWidget(QLabel(label))
-    txt = QRTextEdit()
+    txt = ScanQRTextEdit(parent)
     if default:
         txt.setText(default)
     l.addWidget(txt)

lib/qrscanner.py

@@ -6,28 +6,37 @@ try:
 except ImportError:
     zbar = None
 
+proc = None
 
-def scan_qr(config):
+def init(config):
     if not zbar:
         raise BaseException("\n".join([_("Cannot start QR scanner."),_("The zbar package is not available."),_("On Linux, try 'sudo apt-get install python-zbar'")]))
     device = config.get("video_device", "default")
     if device == 'default':
         device = ''
+    global proc
     proc = zbar.Processor()
     proc.init(video_device=device)
+
+def scan_qr(self):
+    if not zbar:
+        raise BaseException("\n".join([_("Cannot start QR scanner."),_("The zbar package is not available."),_("On Linux, try 'sudo apt-get install python-zbar'")]))
+    if proc is None:
+        raise BaseException("Start proc first")
     proc.visible = True
     while True:
         try:
             proc.process_one()
         except Exception:
             # User closed the preview window
-            return {}
+            return ""
         for r in proc.results:
             if str(r.type) != 'QRCODE':
                 continue
+            # hiding the preview window stops the camera
+            proc.visible = False
             return r.data
 
-
 def _find_system_cameras():
     device_root = "/sys/class/video4linux"
     devices = {} # Name -> device