| # input_pipeline > Gestures > One finger Button Recognizer |
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| Reviewed-on: 2022-10-13 |
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| # Purpose |
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| The one finger button recognizer detects a click or a click-drag on the touchpad. |
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| A click occurs when the user exerts enough force on the touchpad to move the pad itself then |
| release the button. (This is distinct from a tap, which does not move the pad.) |
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| A one finger drag occurs when the user exerts enough force on the touchpad to move the pad |
| itself to trigger the button then move the finger more than threshold. |
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| Notably, this includes discarding any spurious motion that occurs during the click |
| (when a button has been pressed but not yet released). |
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| # State machine |
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| The one finger button recognizer implements the state machine below. |
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|  |
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| The state machine is also available in other formats: |
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| - [state machine as graphviz source](one_button_state_machine.dot) |
| - [state machine as SVG](one_button_state_machine.svg) |
