Trendline: This allows the user to draw straight lines on a cartesian chart. It is a completely custom-developed interaction class and we will see how it can be used with an existing CandleStick as well as a custom MACD chart that we developed in Chapter 4, Creating a Custom Cartesian Chart.

Annotation: This allows the user to annotate a chart by adding an annotation image with a text. This will be a custom interaction, which we will use with our custom MarketClock chart that we developed in Chapter 5, Creating a Custom Polar Chart.

ItemHighlight: This is a custom interaction. It allows the user to show more details about a selected series item. We will leverage the Sencha Charts architecture, modify an existing interaction, and use it on our custom PeriodicTable chart that we developed in Chapter 6, Creating a Custom Spacefilling Chart.