► |  | The Racket Graphical Interface Toolkit

1 | Windowing
2 | Widget Gallery
3 | Windowing Classes
4 | Windowing Functions
5 | Editors
6 | Snip and Style Classes
7 | Editor Classes
8 | Editor Functions
9 | WXME Decoding
10 | Preferences
11 | Dynamic Loading
12 | Startup Actions
13 | Platform Dependencies
| Index

▼ | 3 | Windowing Classes

3.1 | area<%>
3.2 | area-container<%>
3.3 | area-container-window<%>
3.4 | button%
3.5 | canvas<%>
3.6 | canvas%
3.7 | check-box%
3.8 | checkable-menu-item%
3.9 | choice%
3.10 | clipboard-client%
3.11 | clipboard<%>
3.12 | combo-field%
3.13 | control<%>
3.14 | column-control-event%
3.15 | control-event%
3.16 | cursor%
3.17 | dialog%
3.18 | event%
3.19 | frame%
3.20 | gauge%
3.21 | group-box-panel%
3.22 | grow-box-spacer-pane%
3.23 | horizontal-pane%
3.24 | horizontal-panel%
3.25 | key-event%
3.26 | labelled-menu-item<%>
3.27 | list-box%
3.28 | list-control<%>
3.29 | menu%
3.30 | menu-bar%
3.31 | menu-item<%>
3.32 | menu-item%
3.33 | menu-item-container<%>
3.34 | message%
3.35 | mouse-event%
3.36 | pane%
3.37 | panel%
3.38 | popup-menu%
3.39 | printer-dc%
3.40 | radio-box%
3.41 | selectable-menu-item<%>
3.42 | separator-menu-item%
3.43 | scroll-event%
3.44 | slider%
3.45 | subarea<%>
3.46 | subwindow<%>
3.47 | tab-panel%
3.48 | text-field%
3.49 | timer%
3.50 | top-level-window<%>
3.51 | vertical-pane%
3.52 | vertical-panel%
3.53 | window<%>

On this page:

new
get-value
set-value

Inherited methods:
from control<%>
command
from subwindow<%>
reparent
from window<%>
accept-drop-files
client->screen
enable
focus
get-client-handle
get-client-size
get-cursor
get-handle
get-height
get-label
get-plain-label
get-size
get-width
get-x
get-y
has-focus?
is-enabled?
is-shown?
on-drop-file
on-focus
on-move
on-size
on-subwindow-char
on-subwindow-event
on-subwindow-focus
on-superwindow-enable
on-superwindow-show
popup-menu
refresh
screen->client
set-cursor
set-label
show
warp-pointer
from area<%>
get-graphical-min-size
get-parent
get-top-level-window
min-height
min-width
stretchable-height
stretchable-width
from subarea<%>
horiz-margin
vert-margin

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> class

> slider% : class?

superclass: object%

extends: | control<%>

A slider object is a panel item with a handle that the user can drag to change the control’s value. Each slider has a fixed minimum and maximum value.

Whenever the user changes the value of a slider, its callback procedure is invoked. A callback procedure is provided as an initialization argument when each slider is created.

> > constructor

> > (new slider% |
> > |  | [label label] |
> > |  | [min-value min-value] |
> > |  | [max-value max-value] |
> > |  | [parent parent] |
> > | [ | [callback callback] |
> > |  | [init-value init-value] |
> > |  | [style style] |
> > |  | [font font] |
> > |  | [enabled enabled] |
> > |  | [vert-margin vert-margin] |
> > |  | [horiz-margin horiz-margin] |
> > |  | [min-width min-width] |
> > |  | [min-height min-height] |
> > |  | [stretchable-width stretchable-width] |
> > |  | [stretchable-height stretchable-height]]) |

> → (is-a?/c slider%)
> label : (or/c label-string? #f)
> min-value : (integer-in -10000 10000)
> max-value : (integer-in -10000 10000)

> parent

> :

> (or/c (is-a?/c frame%) (is-a?/c dialog%)
> (is-a?/c panel%) (is-a?/c pane%))

> | callback |  | : |  | ((is-a?/c slider%) (is-a?/c control-event%) . -> . any)
> |  |  | = |  | (lambda (b e) (void))

> init-value : (integer-in -10000 10000) = min-value

> style

> :

> (listof (or/c 'horizontal 'vertical 'plain
> 'vertical-label 'horizontal-label
> 'deleted))

> |  |  | = |  | '(horizontal)

> font : (is-a?/c font%) = normal-control-font
> enabled : any/c = #t
> vert-margin : (integer-in 0 1000) = 2
> horiz-margin : (integer-in 0 1000) = 2
> min-width : (integer-in 0 10000) = graphical-minimum-width
> min-height : (integer-in 0 10000) = graphical-minimum-height
> stretchable-width : any/c = (memq 'horizontal style)
> stretchable-height : any/c = (memq 'vertical style)

If label is a string, it is used as the label for the slider. Otherwise, the slider does not display its label.

If & occurs in label, it is specially parsed as for button%.

The min-value and max-value arguments specify the range of the slider, inclusive. The init-value argument optionally specifies the slider’s initial value. If the sequence [min-value, initial-value, maximum-value] is not increasing, an exn:fail:contract exception is raised.

The callback procedure is called (with the event type 'slider) when the user changes the slider’s value.

The style argument must include either 'vertical for a vertical slider, or 'horizontal for a horizontal slider. If style includes 'plain, the slider does not display numbers for its range and current value to the user. If style includes 'vertical-label, then the slider is created with a label above the control; if style does not include 'vertical-label (and optionally includes 'horizontal-label), then the label is created to the left of the slider. If style includes 'deleted, then the slider is created as hidden, and it does not affect its parent’s geometry; the slider can be made active later by calling parent’s add-child method.

The font argument determines the font for the control. For information about the enabled argument, see window<%>. For information about the horiz-margin and vert-margin arguments, see subarea<%>. For information about the min-width, min-height, stretchable-width, and stretchable-height arguments, see area<%>.

> > method

> > (send a-slider get-value) → (integer-in -10000 10000)

Gets the current slider value.

> > method

> > (send a-slider set-value value) → void?

> value : (integer-in -10000 10000)

Sets the value (and displayed position) of the slider. (The control’s callback procedure is not invoked.) If value is outside the slider’s minimum and maximum range, an exn:fail:contract exception is raised.

A slider’s value can be changed by the user clicking the control, and such changes do not go through this method; use the control callback procedure (provided as an initialization argument) to monitor value changes.
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