control the angle

I saw an example of qml. UI Components: Dial Control Example.
I don't understand how to caculate the angel. 
The
angle
property is readonly, instead of this you should usevalue
property. 
@IntruderExcluder
Yes. I know what you mean.
Here is the code.I just don't know "angle: Math.min(Math.max(130, root.value*2.6  130), 133)" mean.Image { id: needle x: 98; y: 33 antialiasing: true source: "needle.png" transform: Rotation { id: needleRotation origin.x: 5; origin.y: 65 //! [needle angle] **angle: Math.min(Math.max(130, root.value*2.6  130), 133)** Behavior on angle { SpringAnimation { spring: 1.4 damping: .15 } } //! [needle angle] } }

@chris_rookie said in control the angle:
I just don't know "angle: Math.min(Math.max(130, root.value*2.6  130), 133)" mean.
It's a formula to calculate the angle for drawing the needle :)
And the angle is then used to animate a Behavior:
A Behavior defines the default animation to be applied whenever a particular property value changes.
In your case the property that changes is angle which in turn is dependent on root.value

@PabloJRogina
Thanks for your answer.
After reading this page ```
https://doc.qt.io/qt5/qmlqtquickrotation.htmlI think I understand what "angle: Math.min(Math.max(130, root.value*2.6  130), 133)" mean

@IntruderExcluder
Thanks for your answer.