how to add PathLine to ShapePath with a Repeater? - qt

Question

UPDATE 1 - i can get it to work using Javascript - but that seems to be a little bit unoptimized (from 2-3% to 30% load with qmlscene.exe when activated) - complete recreation when the model changes (its not ever growing), is that the only way or is there a more "declarative" style available?
How can i add a PathLine to a ShapePath based on a Model?
i know how to use a Repeater from outside of Items but not how to implode them inside of Items
do i need some sort of Repeater-Delegate on pathElements?
and i don't want to use the LineSeries component
import QtQuick.Shapes 1.15
import QtQuick 2.15
Shape {
ListModel {
id: myPositions
ListElement { x: 0; y:38 }
ListElement { x: 10; y: 28 }
ListElement { x: 20; y: 30 }
ListElement { x: 30; y: 14 }
}
ShapePath {
strokeColor: "black"
strokeWidth: 1
fillColor: "transparent"
startX: 0
startY: 0
PathLine { x: 0; y: 38 }
PathLine { x: 10; y: 28 }
PathLine { x: 20; y: 30 }
PathLine { x: 30; y: 14 }
// Repeater {
// model: myPositions
// PathLine { x: model.x; y: model.y }
// }
}
}
UPDATE 1
import QtQuick.Shapes 1.15
import QtQuick 2.15
Shape {
ListModel {
id: myPositions
}
function getRandomInt(min, max) {
min = Math.ceil(min);
max = Math.floor(max);
return Math.floor(Math.random() * (max - min + 1)) + min;
}
Timer
{
interval: 100
running: true
repeat: true
property real myX: 0
onTriggered: {
myPositions.append({"x":myX, "y":getRandomInt(0,30)})
myX = myX + 10
}
}
function createPathLineElements(positionsModel, shapePath)
{
var pathElements = []
for (var i = 0; i < positionsModel.count; i++)
{
var pos = myPositions.get(i)
var pathLine = Qt.createQmlObject('import QtQuick 2.15; PathLine {}',
shapePath);
pathLine.x = pos.x
pathLine.y = pos.y
pathElements.push(pathLine)
}
return pathElements
}
ShapePath {
id: myPath
strokeColor: "black"
strokeWidth: 1
fillColor: "transparent"
startX: 0
startY: 0
pathElements: createPathLineElements(myPositions, myPath)
}
}

Answer 1

Use an Instantiator:
Shape {
ListModel {
id: myPositions
}
function getRandomInt(min, max) {
min = Math.ceil(min);
max = Math.floor(max);
return Math.floor(Math.random() * (max - min + 1)) + min;
}
Timer {
interval: 100
running: true
repeat: true
property real myX: 0
onTriggered: {
myPositions.append({"x":myX, "y":getRandomInt(0,30)})
myX = myX + 10
}
}
ShapePath {
id: myPath
fillColor: "transparent"
strokeColor: "red"
capStyle: ShapePath.RoundCap
joinStyle: ShapePath.RoundJoin
strokeWidth: 3
strokeStyle: ShapePath.SolidLine
}
Instantiator {
model: myPositions
onObjectAdded: myPath.pathElements.push(object)
PathLine {
x: model.x
y: model.y
}
}
}

Answer 2

You can't use repeater in that element.
The most performant way is to use QQuickItem in order to create a custom Item which draws incremental path.
Yet another simpler ways are:
1- Use PathSvg element and set its path runtime like below:
ShapePath {
fillColor: "transparent"
strokeColor: "red"
capStyle: ShapePath.RoundCap
joinStyle: ShapePath.RoundJoin
strokeWidth: 3
strokeStyle: ShapePath.SolidLine
PathSvg { id: ps; path: parent.p } //<== fill path property using js
property string p: ""
Component.onCompleted: {
for ( var i = 0; i < myModel.count; i++) {
p += "L %1 %2".arg(myModel.get(i).x).arg(myModel.get(i).y);
}
ps.path = p;
}
}
2- If you know steps, so you can pre-declare all PathLines and then set their values runtime. Just like a heart rate line on a health care monitor.