From: Peter Hutterer Date: Mon, 22 Dec 2014 23:47:39 +0000 (+1000) Subject: doc: move the wiki's palm detection docs to here X-Git-Tag: 0.8.0~41 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=380137ca29b992be857f67c99f60bbeb11146fd7;p=platform%2Fupstream%2Flibinput.git doc: move the wiki's palm detection docs to here Signed-off-by: Peter Hutterer --- diff --git a/doc/Makefile.am b/doc/Makefile.am index 746418a..b4b5d54 100644 --- a/doc/Makefile.am +++ b/doc/Makefile.am @@ -11,6 +11,7 @@ header_files = \ $(srcdir)/clickpad-softbuttons.dox \ $(srcdir)/device-configuration-via-udev.dox \ $(srcdir)/normalization-of-relative-motion.dox \ + $(srcdir)/palm-detection.dox \ $(srcdir)/scrolling.dox \ $(srcdir)/seats.dox \ $(srcdir)/t440-support.dox \ @@ -21,6 +22,7 @@ diagram_files = \ $(srcdir)/dot/seats-sketch-libinput.gv \ $(srcdir)/svg/button-scrolling.svg \ $(srcdir)/svg/edge-scrolling.svg \ + $(srcdir)/svg/palm-detection.svg \ $(srcdir)/svg/twofinger-scrolling.svg html/index.html: libinput.doxygen $(header_files) $(diagram_files) diff --git a/doc/palm-detection.dox b/doc/palm-detection.dox new file mode 100644 index 0000000..4e839e6 --- /dev/null +++ b/doc/palm-detection.dox @@ -0,0 +1,52 @@ +/** +@page palm_detection Palm detection + +Palm detection tries to identify accidental touches while typing. + +On most laptops typing on the keyboard generates accidental touches on the +touchpad with the palm (usually the area below the thumb). This can lead to +cursor jumps or accidental clicks. + +Interference from a palm depends on the size of the touchpad and the position +of the user's hand. Data from touchpads showed that almost all palm events on a +Lenovo T440 happened in the left-most and right-most 5% of the touchpad. The +T440 series has one of the largest touchpads, other touchpads are less +affected by palm touches. + +@section palm_exclusion_zones Palm exclusion zones + +libinput enables palm detection on the edge of the touchpad. Two exclusion +zones are defined on the left and right edge of the touchpad. +If a touch starts in the exclusion zone, it is considered a palm and the +touch point is ignored. However, for fast cursor movements across the +screen, it is common for a finger to start inside an exclusion zone and move +rapidly across the touchpad. libinput detects such movements and avoids palm +detection on such touch sequences. + +In the diagram below, the exclusion zones are painted red. +Touch 'A' starts inside the exclusion zone and moves +almost vertically. It is considered a palm and ignored for cursor movement, +despite moving out of the exclusion zone. + +Touch 'B' starts inside the exclusion zone but moves horizontally out of the +zone. It is considered a valid touch and controls the cursor. + +@image html palm-detection.svg + +@section trackpoint-disabling Palm detection during trackpoint use + +If a device provides a trackpoint, it is +usually located above the touchpad. This increases the likelyhood of +accidental touches whenever the trackpoint is used. + +libinput disables the touchpad whenver it detects trackpoint activity for a +certain timeout until after trackpoint activity stops. Touches generated +during this timeout will not move the pointer, and touches started during +this timeout will likewise not move the pointer (allowing for a user to rest +the palm on the touchpad while using the trackstick). +If the touchpad is disabled, the @ref t440_support "top software buttons" +remain enabled. + + +*/ diff --git a/doc/svg/palm-detection.svg b/doc/svg/palm-detection.svg new file mode 100644 index 0000000..9fb6077 --- /dev/null +++ b/doc/svg/palm-detection.svg @@ -0,0 +1,122 @@ + + + + + + + + + + + + + + + + + + + + + + + + A + B + + + +