MOUSESCROLLSIZE(3) MOUSESCROLLSIZE(3)
NAME
mousescrollsize - compute mouse scroll increment
SYNOPSIS
#include <draw.h>
int mousescrollsize(int maxlines)
DESCRIPTION
Mousescrollsize computes the number of lines of text that
should be scrolled in response to a mouse scroll wheel
click. Maxlines is the number of lines visible in the text
window.
The default scroll increment is one line. This default can
be overridden by setting the $mousescrollsize environment
variable to an integer, which specifies a constant number of
lines, or to a real number followed by a percent character,
indicating that the scroll increment should be a percentage
of the total number of lines in the window. For example,
setting $mousescrollsize to 50% causes a half-window scroll
increment.
Mousescrollsize is used by 9term(1) and acme(1) to set their
scrolling behavior.
SOURCE
/usr/local/plan9/src/libdraw/scroll.c
SEE ALSO
9term(1), acme(1)
BUGS
Libdraw expects up and down scroll wheel events to be
expressed as clicks of mouse buttons 4 and 5, but the
XFree86 default is to ignore the scroll wheel. To enable
the scroll wheel, change your InputDevice section of
XF86Config-4 to look like:
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Device" "/dev/psaux"
# next four lines enable scroll wheel as buttons 4 and 5
Option "Buttons" "5"
Option "Emulate3Buttons" "off"
Option "Protocol" "ImPS/2"
Option "ZAxisMapping" "4 5"
EndSection
Page 1 Plan 9 (printed 10/29/25)
MOUSESCROLLSIZE(3) MOUSESCROLLSIZE(3)
Page 2 Plan 9 (printed 10/29/25)