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51 lines
1.9 KiB
Text
51 lines
1.9 KiB
Text
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/**
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@page scrolling Scrolling
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libinput supports three different types of scrolling behavior.
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@section twofinger_scrolling Two-finger scrolling
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The default on two-finger capable touchpads (almost all modern touchpads are
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capable of detecting two fingers). Scrolling is triggered by two fingers
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being placed on the surface of the touchpad, then moving those fingers
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vertically or horizontally.
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@image html twofinger-scrolling.svg "Vertical and horizontal two-finger scrolling"
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For scrolling to trigger, a built-in distance threshold has to be met but once
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engaged any movement will scroll. In other words, to start scrolling a
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sufficiently large movement is required, once scrolling tiny amounts of
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movements will translate into tiny scroll movements.
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Scrolling in both directions at once is possible by meeting the required
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distance thresholds to enable each direction separately.
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@section edge_scrolling Edge scrolling
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On some touchpads, edge scrolling is available, triggered by moving a single
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finger along the right edge (vertical scroll) or bottom edge (horizontal
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scroll).
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@image html edge-scrolling.svg "Vertical and horizontal edge scrolling"
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Due to the layout of the edges, diagonal scrolling is not possible.
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Edge scrolling conflicts with @ref clickpad_softbuttons and is
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not usually available on clickpads.
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@section button_scrolling On-Button scrolling
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Scrolling when a button is held down is available on selected devices. The
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motion of a device is converted into scrolling motion.
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For example, Lenovo devices provide a
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<a href="http://en.wikipedia.org/wiki/Pointing_stick">pointing stick</a> that emulates
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scroll events when the trackstick's middle mouse button is held down.
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@image html button-scrolling.svg "Button scrolling"
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Note that libinput's @ref t440_support enables the use of the middle
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button for button scrolling (even when the touchpad is disabled).
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*/
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