kivy: fix qrcodewidget (only update from gui thread)

gui/kivy/uix/qrcodewidget.py

@@ -42,14 +42,9 @@ Builder.load_string('''
 class QRCodeWidget(FloatLayout):
 
     data = StringProperty(None, allow_none=True)
-
     background_color = ListProperty((1, 1, 1, 1))
-
     foreground_color = ListProperty((0, 0, 0, 0))
 
-
-    #loading_image = StringProperty('gui/kivy/theming/loading.gif')
-
     def __init__(self, **kwargs):
         super(QRCodeWidget, self).__init__(**kwargs)
         self.data = None
@@ -57,21 +52,11 @@ class QRCodeWidget(FloatLayout):
         self._qrtexture = None
 
     def on_data(self, instance, value):
-        print "on data", value
         if not (self.canvas or value):
             return
-        img = self.ids.get('qrimage', None)
-
-        if not img:
-            # if texture hasn't yet been created delay the texture updation
-            Clock.schedule_once(lambda dt: self.on_data(instance, value))
-            return
-
-        #Thread(target=partial(self.update_qr, )).start()
         self.update_qr()
 
     def set_data(self, data):
-        print "set data", data
         if self.data == data:
             return
         MinSize = 210 if len(data) < 128 else 500
@@ -98,7 +83,7 @@ class QRCodeWidget(FloatLayout):
         # currently unused, do we need this?
         self._texture_size = size
 
-    def _create_texture(self, k, dt):
+    def _create_texture(self, k):
         self._qrtexture = texture = Texture.create(size=(k,k), colorfmt='rgb')
         # don't interpolate texture
         texture.min_filter = 'nearest'
@@ -107,32 +92,24 @@ class QRCodeWidget(FloatLayout):
     def update_texture(self):
         if not self.qr:
             return
-
         matrix = self.qr.get_matrix()
         k = len(matrix)
-        # create the texture in main UI thread otherwise
-        # this will lead to memory corruption
-        Clock.schedule_once(partial(self._create_texture, k), -1)
+        # create the texture
+        self._create_texture(k)
         buff = []
         bext = buff.extend
         cr, cg, cb, ca = self.background_color[:]
         cr, cg, cb = cr*255, cg*255, cb*255
-
         for r in range(k):
             for c in range(k):
                 bext([0, 0, 0] if matrix[r][c] else [cr, cg, cb])
-
         # then blit the buffer
         buff = ''.join(map(chr, buff))
-        # update texture in UI thread.
-        Clock.schedule_once(lambda dt: self._upd_texture(buff), .1)
+        # update texture
+        self._upd_texture(buff)
 
     def _upd_texture(self, buff):
         texture = self._qrtexture
-        if not texture:
-            # if texture hasn't yet been created delay the texture updation
-            Clock.schedule_once(lambda dt: self._upd_texture(buff), .1)
-            return
         texture.blit_buffer(buff, colorfmt='rgb', bufferfmt='ubyte')
         img =self.ids.qrimage
         img.anim_delay = -1

gui/kivy/uix/screens.py

@@ -308,7 +308,7 @@ class ReceiveScreen(CScreen):
     @profiler
     def update_qr(self):
         uri = self.get_URI()
-        qr = self.screen.ids.get('qr')
+        qr = self.screen.ids.qr
         qr.set_data(uri)
 
     def do_copy(self):

gui/kivy/uix/ui_screens/history.kv

@@ -42,7 +42,7 @@
             color: .699, .699, .699, 1
             font_size: '13sp'
             shorten: True
-            text: root.message if root.message else ' '
+            text: root.message
         Widget
     CardLabel:
         halign: 'right'