[Interest] Animating a gradient

[Gian Maxera]

Ok, that’s explain also because onPositionChanged does not work.
The property has no signal notify changes. So, it means you cannot do what you want.

So, my workaround is:
 - define a property and animate this property
 - refer this property into gradient

Rectangle {
  id: myRect
  property real gradPosition: 0.98
  gradient: Gradient {
      GradientStop{ … ; position: myRect.gradPosition }
 …

Ciao,
Gianluca.


> On 18 Nov 2015, at 15:20, Jason H <jhihn at gmx.com> wrote:
> 
> A fantastic suggestion! However when I tried it I got:
> QQmlExpression: Expression qrc:/NextBar.qml:33:40 depends on non-NOTIFYable properties:
>    QQuickGradientStop::position
> 
> Does anyone know why these aren't NOTIFYable?
> 
> 
>> Sent: Tuesday, November 17, 2015 at 4:16 PM
>> From: Gianluca <gmaxera at gmail.com>
>> To: "Jason H" <jhihn at gmx.com>
>> Cc: "interest at qt-project.org" <interest at qt-project.org>
>> Subject: Re: [Interest] Animating a gradient
>> 
>> Hello Jason,
>> why you don’t simple use property binding ?
>> 
>> GradientStop { id: gs2; position: gs1.position+0.1; color: "dodgerblue" }
>> 
>> and remove completely onPositionChanged
>> 
>> Ciao,
>> Gianluca.
>> 
>> 
>> Il giorno 17/nov/2015, alle ore 20:39, Jason H <jhihn at gmx.com> ha scritto:
>> 
>>> I want to animate a gradient, but onPositionChanged gives an error, even though I can animate it. What am I doing wrong?
>>> 
>>> 
>>> Item {
>>> 	property alias color: container.color
>>> 	Component.onCompleted: anim.start()
>>> 	Rectangle {
>>> 		id: container
>>> 		width: parent.width * .9
>>> 		height : parent.height / 2
>>> 		anchors.centerIn: parent
>>> 		Rectangle {
>>> 			anchors.centerIn: parent
>>> 			width: container.height /2
>>> 			height: container.width
>>> 			rotation: -90
>>> 			gradient:Gradient {
>>> 					GradientStop { id: gs0; position: 0.00; color: "dodgerblue" }
>>> 					GradientStop {
>>> 						id: gs1;
>>> 						position: 0.98;
>>> 						color: "white";
>>> 						onPositionChanged: { // Cannot assign to non-existent property "onPositionChanged"
>>> 							gs2.position = position +.01
>>> 						}
>>> 					}
>>> 					GradientStop { id: gs2; position: 0.99; color: "dodgerblue" }
>>> 					GradientStop { id: gs3; position: 1.00; color: "dodgerblue" }
>>> 			}
>>> 		}
>>> 	}
>>> 
>>> 	NumberAnimation {
>>> 		id: anim
>>> 		target: gs1
>>> 		property: "position"
>>> 		duration: 2000
>>> 		easing.type: Easing.InOutQuad
>>> 		loops: Animation.Infinite
>>> 		from: .98
>>> 		to: 0
>>> 	}
>>> }
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>>> Interest at qt-project.org
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>> 
>>