Java Reference
In-Depth Information
When the variable panel is added to a Scene instance (not shown) and the application is
executed, you will end up with what is shown in the next screenshot:
How it works...
The previous code shows how to use the Slider control to create a color picker. It declares
three Slider instances to represent a color element including rSlide for red, gSlide for
green, and bSlide for blue. The most pertinent properties of the Slider are min:Number
and max:Number . These properties specify the range of values that the slider represents. In
our code, each slider instance is declared with min=0 and max=255, corresponding to the
numeric ranges of the RGB color values. The user can only slide the knob between the min
value and the max values (inclusive).
As the user drags the knob, the slider updates its value:Number property. This property
indicates the currently selected value based on the knob position on the track. For instance,
when the user slides the knob all the way to the right-hand side, the value property of the
slider will be set to 255 .
The Circle instance circ is used to reflect the color changes as the slider values are updated.
To do this, the fill:Color property of the circle is assigned a Color instance, where each
element of the RGB color is bound to slider rSlide.value , gSlide.value , and bSlide.
value respectively, as shown in the next code snippet. Whenever a color value changes, the
bind generates a new Color instance to apply to the circle.
var circ = Circle {
fill : bind Color.rgb(
rSlide.value, gSlide.value, bSlide.value
See also
F Introduction
F Creating a form with JavaFX controls
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