The HighPass-LowPass Roofing Filter was created by John Ehlers (Cycle Analytics For Traders pg.78)

This is a variation of a roofing filter that will let you know which direction the stock is trending. If it falls below 0 then the stock is in a downtrend and if it rises above 0 then it is an uptrend. Buy when the indicator line is green and sell when it is red.

The version for MetaTrader 4 will not be presented here. You can download it along with the source code through my Telegram channel. The link to the channel is in my profile. Don't forget to subscribe!