QML Scrolling Digits

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How to create scrolling digits component

Here is one way to easily create a scrolling digits component.

https://www.youtube.com/watch?v=KLE4FdGc12U

Code

First we create a component for digits:

Digit.qml

import QtQuick 1.1

Rectangle {
 id: digitItem
 width: size
 height: size

clip: true

gradient: Gradient {
 GradientStop {
 position: 0.0
 color: "black"
 }

GradientStop {
 position: 0.5
 color: "#222222"
 }

GradientStop {
 position: 1.0
 color: "black"
 }
 }

border.color: "black"
 border.width: 1

property int digit: 0
 property int size: 20

onDigitChanged: { digitPath.currentIndex = digit; }

PathView {
 id: digitPath

width: digitItem.size
 height: digitItem.size * 10

interactive: false

anchors.centerIn: parent

model: [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ]

delegate: Text {
 width: digitItem.size
 height: digitItem.size

text: modelData;

color: "white";

horizontalAlignment: Text.AlignHCenter;
 verticalAlignment: Text.AlignVCenter;

font.pointSize: digitItem.size-4;
 }

preferredHighlightBegin: 0.5
 preferredHighlightEnd: 0.5

path: Path {
 startX: digitPath.width / 2
 startY: 0

PathLine { x: digitPath.width / 2; y: digitPath.height }
 }
 }
}

The component is just a Rectangle with gradient. In its center we place a PathView and set clipping to true, so only the selected digit will be visible.

Than we create the ScrollingDigits component:

ScrollingDigits.qml

import QtQuick 1.1

Row {
 id: scrollingDigits

property int number: 0
 property int positions: 5

Repeater {
 id: rep

model: scrollingDigits.positions

Digit {
 }
 }

onNumberChanged: {

var tmp = number

for( var i = 0; i < positions; ++i ) {
 rep.itemAt( positions - i - 1).digit = tmp % 10
 tmp = Math.floor( tmp / 10 )
 }
 }
}

We add two properties to Row: number and positions . number contains the number we want to display and positions is the number of digits we want.

Example

main.qml

import QtQuick 1.1

Rectangle
{
 width: 400
 height: 400

color: "gray"

ScrollingDigits {
 anchors.centerIn: parent

positions: 4

NumberAnimation on number {
 from: 15; to: 100
 duration: 50000
 }
 }
}