Electrum QR scanner

diff --git a/lib/gui_qt.py b/lib/gui_qt.py
index 6784481..f0e58f9 100644
--- a/lib/gui_qt.py
+++ b/lib/gui_qt.py
@@ -27,6 +27,12 @@ except:
     print_error("on Linux systems, you may try 'sudo apt-get install python-qt4'")
     sys.exit(1)

+try:
+    import zbar
+except ImportError:
+    print_error("Install zbar package to enable QR scans")
+    zbar = None
+
 from PyQt4.QtGui import *
 from PyQt4.QtCore import *
 import PyQt4.QtCore as QtCore
@@ -432,6 +438,36 @@ class ElectrumWindow(QMainWindow):
         self.history_list.setCurrentItem(self.history_list.topLevelItem(0))


+    def scan_qr(self):
+        from urlparse import urlparse, parse_qs
+
+        proc = zbar.Processor()
+        proc.init()
+        proc.visible = True
+
+        while True:
+            try:
+                proc.process_one()
+            except:
+                # User closed the preview window
+                return {}
+
+            for r in proc.results:
+                if str(r.type) != 'QRCODE':
+                    continue

+
+                qrcode = r.data
+                if ':' not in qrcode:
+                    # It's just an address (not BIP21)
+                    return {'address': qrcode}
+
+                if '//' not in qrcode:
+                    # Workaround for urlparse, it don't handle bitcoin: URI properly
+                    qrcode = qrcode.replace(':', '://')
+                uri = urlparse(qrcode)
+                print uri
+                return {'address': uri.netloc}#, 'amount': None, 'label': None}
+
     def create_send_tab(self):
         w = QWidget()

@@ -443,6 +479,21 @@ class ElectrumWindow(QMainWindow):
         self.payto_e = QLineEdit()
         grid.addWidget(QLabel(_('Pay to')), 1, 0)
         grid.addWidget(self.payto_e, 1, 1, 1, 3)
+
+        def fill_from_qr():
+            qrcode = self.scan_qr()
+            if 'address' in qrcode:
+                self.payto_e.setText(qrcode['address'])
+            if 'amount' in qrcode:
+                self.amount_e.setText(str(qrcode['amount']))
+            if 'label' in qrcode:
+                self.message_e.setText(qrcode['label'])
+
+        if zbar:
+            b = QPushButton(_("Scan QR code"))
+            b.clicked.connect(fill_from_qr)
+            grid.addWidget(b, 1, 5)
+
         grid.addWidget(HelpButton(_('Recipient of the funds.') + '\n\n' + _('You may enter a Bitcoin address, a label from your list of contacts (a list of completions will be proposed), or an alias (email-like address that forwards to a Bitcoin address)')), 1, 4)