►The Racket Graphical Interface Toolkit
▼3 Windowing Classes
On this page:
new
get-direction
get-event-type
get-position
set-direction
set-event-type
set-position
Inherited methods:
from event%
get-time-stamp
set-time-stamp
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class

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.

constructor

(new scroll-event% 
    [[event-type event-type] 
    [direction direction] 
    [position position] 
    [time-stamp time-stamp]]) 
 → (is-a?/c scroll-event%)
  event-type : 
(or/c 'top 'bottom 'line-up 'line-down
      'page-up 'page-down 'thumb)
 = 'thumb
  direction : (or/c 'horizontal 'vertical) = 'vertical
  position : dimension-integer? = 0
  time-stamp : exact-integer? = 0
See the corresponding get- and set- methods for information about event-type, direction, position, and time-stamp.

method

(send a-scroll-event get-direction)

 → (or/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.

method

(send a-scroll-event get-event-type)

 → 
(or/c 'top 'bottom 'line-up 'line-down
      'page-up 'page-down 'thumb)
Returns the type of the event, one of the following:

method

(send a-scroll-event get-position) → dimension-integer?

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

method

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

  direction : (or/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.

method

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

  type : 
(or/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.

method

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

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

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