SLIDER item type
Defines a slider form item.
SLIDER item basics
The SLIDER
form item defines a field where the user can set a value in a given
range, such as a typical audio volume control widget where you can grab the slider handle to change
the value.
Use a SMALLINT
or INTEGER
variable with a
SLIDER
form item, larger types like BIGINT
or
DECIMAL
are not supported.
Defining a SLIDER
A SLIDER
field allows the user to move a handle along a horizontal or vertical
groove and translates the handle's position into a value within the legal range.
The VALUEMIN
and VALUEMAX
attributes define
respectively the lower and upper integer limit of the slider information. Any value outside this
range will not be displayed. The step between two marks is defined by the STEP
attribute. If
VALUEMIN
and/or VALUEMAX
are not specified, they default
respectively to 0 (zero) and 5.
The ORIENTATION
attribute defines whether the SLIDER
is displayed vertically or horizontally.
This item type is not designed for CONSTRUCT
, as the user can only select one
value.
Front-ends support different presentation and behavior options, which can be controlled by a
STYLE
attribute. For more
details, see Style attributes common to all elements.
Detecting SLIDER item selection
To inform the dialog when a value changes, define an ON CHANGE
block for the
SLIDER
field. The program can then react immediately to user changes in the
field:
-- Form file (grid layout)
SLIDER s1 = options.opts_volume,
VALUEMIN=0, VALUEMAX=100;
-- Program file:
ON CHANGE opts_volume
-- A value changed in the slider
For more details, see Reacting to field value changes.
Where to use a SLIDER
SLIDER
form item can be defined in different ways:- With an item tag and a SLIDER item definition in a grid-layout
container (
GRID
,SCROLLGRID
andTABLE
). - As a SLIDER stack item in a
STACK
container.