qt piechart: show a full circle if there is only one item in the list

electrum/gui/qt/balance_dialog.py

@@ -68,8 +68,13 @@ class PieChartObject:
         alpha = 0
         s = 0
         for name, color, amount in self._list:
-            delta = int(16 * 360 * amount/total)
             qp.setBrush(color)
+            if amount == 0:
+                continue
+            elif amount == total:
+                qp.drawEllipse(self.R)
+            else:
+                delta = int(16 * 360 * amount/total)
                 qp.drawPie(self.R, alpha, delta)
                 alpha += delta
         qp.end()