input_pipeline > Gestures > Scroll Recognizer

Reviewed-on: 2022-07-20

Purpose

The scroll recognizer detects 2 finger swipe on the touchpad, and converts all related touchpad events to mouse wheel events.

A scroll occurs when the user places 2 fingers on the touchpad surface. And 2 fingers move approximately horizontal or vertical.

State machine

The scroll recognizer implements the state machine below.

The state machine is also available in other formats:

• state machine as graphviz source
• state machine as SVG

The scroll recognizer tolerate a certain degree of angle in the direction.