Angle calculation is performed by calculating the tangent over a delta interval. Normalization is required to make the angle independent of the price range.
This script is meant to be used together with the corresponding EMAs on the candle pane. Non normalized view shows a more realistic angle condition but, if intended to be used with the CEMAS indicator, normalized view should be used.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.