Page 330 Table of Contents Index Page 332
Chapters
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
A, B, C, D, E


CHAPTER 30. GADGETS


30.4.5 The slider Gadget

The slider gadget corresponds to a slider.

=> slider [Class]
The class that implements a slider. This is a subclass of value-gadget, oriented-gadget,
range-gadget-mixin, and labelled-gadget.

=> :drag-callback [Init Arg]
=> :show-value-p [Init Arg]
Specifies the drag callback for the slider, and whether the slider should show its current value.

=> gadget-show-value-p slider [Generic Function]
Returns true if the slider shows its value, otherwise returns false

=> slider-drag-callback slider [Generic Function]
Returns the function that will be called when the indicator of the slider is dragged. This function
will be invoked with a two arguments, the slider and the new value.

When this function returns nil, that indicates that there is no drag callback for the gadget.

=> drag-callback slider client gadget-id value [Callback Generic Function]
This callback is invoked when the value of the slider is changed while the indicator is being
dragged. This is implemented by calling the function stored in slider-drag-callback with
two arguments, the slider and the new value.

The value-changed-callback is invoked only after the indicator is released after dragging it.

=> gadget-value (button slider) [Method]
Returns a real number within the specified range.

=> slider-pane [Class]
The class that implements a portable slider; a subclass of slider.

30.4.6 The radio-box Gadget

A radio box is a special kind of gadget that constrains one or more toggle buttons. At any one
time, only one of the buttons managed by the radio box may be "on". The contents of a radio
box are its buttons, and as such a radio box is responsible for laying out the buttons that it
contains. A radio box is a client of each of its buttons so that the value of the radio box can be
properly computed.

Page 330 Table of Contents Index Page 332
Chapters
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
A, B, C, D, E