| 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
`