Merge pull request #4145 from hoeckxer/custom_stoploss_doc_addition

Added an example with a positive offset for a custom stoploss

docs/strategy-advanced.md

@@ -119,6 +119,35 @@ class AwesomeStrategy(IStrategy):
         return -0.15
 ```
 
+#### Trailing stoploss with positive offset
+
+Use the initial stoploss until the profit is above 4%, then use a trailing stoploss of 50% of the current profit with a minimum of 2.5% and a maximum of 5%.
+
+Please note that the stoploss can only increase, values lower than the current stoploss are ignored.
+
+``` python
+from datetime import datetime, timedelta
+from freqtrade.persistence import Trade
+
+class AwesomeStrategy(IStrategy):
+
+    # ... populate_* methods
+
+    use_custom_stoploss = True
+
+    def custom_stoploss(self, pair: str, trade: Trade, current_time: datetime, current_rate: float,
+                        current_profit: float, **kwargs) -> float:
+
+        if current_profit < 0.04:
+            return -1 # return a value bigger than the inital stoploss to keep using the inital stoploss
+
+        # After reaching the desired offset, allow the stoploss to trail by half the profit
+        desired_stoploss = current_profit / 2 
+
+        # Use a minimum of 2.5% and a maximum of 5%
+        return max(min(desired_stoploss, 0.05), 0.025)
+```
+
 #### Absolute stoploss
 
 The below example sets absolute profit levels based on the current profit.