GUI: PLT Graphics Toolkit

1`` | Overview
- | Windowing
- | Drawing
- | Editor
2`` | Reference
- | Windowing Classes
- | Windowing Functions
- | Drawing Classes
- | Drawing Functions
- | Editor Classes
- | Editor Functions
- | WXME Decoding
3`` | Configuration
4`` | Dynamic Loading
| Index

On this page:

get-value
set-value

Inherited methods:
from control<%>
command
get-font
from window<%>
accept-drop-files
client->screen
enable
focus
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-superwindow-enable
on-superwindow-show
popup-menu
refresh
screen->client
set-cursor
set-label
show
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

Version: 4.0.2
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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.

(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? false/c)
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 (one-of/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<%>.

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

Gets the current slider value.

(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 controlcallback procedure (provided as an initialization argument) to monitor value changes.

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