scroll-event% : class?

superclass: event%

A scroll-event% object contains information about a scroll event. An instance of scroll-event% is always provided to on-scroll.

See get-event-type for a list of the scroll event types.

(new scroll-event%  [ [event-type event-type]       [direction direction]       [position position]       [time-stamp time-stamp]])

→ (is-a?/c scroll-event%)

event-type   :   (one-of/c 'top 'bottom 'line-up 'line-down           'page-up 'page-down 'thumb)       =   'thumb

direction : (one-of/c 'horizontal 'vertical) = 'vertical

position : (integer-in 0 10000) = 0

time-stamp : (and/c exact? integer?) = 0

See the corresponding get- and set- methods for information about event-type, direction, position, and time-stamp.

(send a-scroll-event get-direction)

→ (one-of/c 'horizontal 'vertical)

Gets the identity of the scrollbar that was modified by the event, either the horizontal scrollbar or the vertical scrollbar, as 'horizontal or 'vertical, respectively. See also set-direction.

(send a-scroll-event get-event-type)

→ (one-of/c 'top 'bottom 'line-up 'line-down 'page-up 'page-down 'thumb)

Returns the type of the event, one of the following:

• 'top – user clicked a scroll-to-top button

• 'bottom – user clicked a scroll-to-bottom button

• 'line-up – user clicked an arrow to scroll up or left one step

• 'line-down – user clicked an arrow to scroll down or right one step

• 'page-up – user clicked an arrow to scroll up or left one page

• 'page-down – user clicked an arrow to scroll down or right one page

• 'thumb – user dragged the scroll position indicator

(send a-scroll-event get-position) → (integer-in 0 10000)

Returns the position of the scrollbar after the action triggering the event. See also set-position.

(send a-scroll-event set-direction direction) → void?

direction : (one-of/c 'horizontal 'vertical)

Sets the identity of the scrollbar that was modified by the event, either the horizontal scrollbar or the vertical scrollbar, as 'horizontal or 'vertical, respectively. See also get-direction.

(send a-scroll-event set-event-type type) → void?

type   :   (one-of/c 'top 'bottom 'line-up 'line-down           'page-up 'page-down 'thumb)

Sets the type of the event. See get-event-type for information about each event type.

(send a-scroll-event set-position position) → void?

position : (integer-in 0 10000)

Records the position of the scrollbar after the action triggering the event. (The scrollbar itself is unaffected). See also get-position.