waveform: add LogWaveform

artiq/dashboard/waveform.py

@@ -99,6 +99,34 @@ class ReceiverProxyClient(_BaseProxyClient):
         await self.receiver.close()
 
 
+class LogWaveform(_BaseWaveform):
+    def __init__(self, name, width, parent=None):
+        _BaseWaveform.__init__(self, name, width, parent, pen=None, symbol="x")
+
+    def onDataChange(self, data):
+        try:
+            x_data = zip(*data)[0]
+            self.plot_data_item.setData(
+                x=x_data, y=np.ones(len(x_data)))
+            old_msg = ""
+            old_x = 0
+            for x, msg in data:
+                if x == old_x:
+                    old_msg += "\n" + msg
+                else:
+                    lbl = pg.TextItem(old_msg)
+                    self.addItem(lbl)
+                    lbl.setPos(old_x, 1)
+                    old_msg = msg
+                    old_x = x
+            lbl = pg.TextItem(old_msg)
+            self.addItem(lbl)
+            lbl.setPos(old_x, 1)
+        except:
+            logger.error('Error caught when displaying waveform: {}'.format(self.name), exc_info=True)
+            self.plot_data_item.setData(x=[], y=[])
+
+
 class _WaveformModel(QtCore.QAbstractTableModel):
     def __init__(self):
         self.backing_struct = []