QML append new PathCurve elements to List<PathElements> in ShapePath - qt

Question

To be specific: I want to connect several Points on a Map with a spline curve. New points can be added with a Mouseclick and should also be connected to the existing Path. The points are stored within a model, so I can access them also in C++.
Unfortunately I can't figure out, how I can append new PathCurve elements to the existing List in the Shape::ShapePath Object.
I expected that something like this should work:
...
MapQuickItem {
coordinate: QtPositioning.coordinate(0.0000, 0.0000)
sourceItem: Shape {
id: myShape
anchors.fill: parent
vendorExtensionsEnabled: false
ShapePath {
id: myPath
strokeColor: "black"
strokeWidth: 2
capStyle: ShapePath.RoundCap
fillColor: "transparent"
startX: 0; startY: 0
}
}
zoomLevel: 15
}
MouseArea {
anchors.fill: parent
onClicked: {
var coord = parent.toCoordinate(Qt.point(mouse.x,mouse.y))
myPath.pathElements.push( new PathCurve(mouse.x, mouse.y) ) //does not work
}
}
I also tried to fill the PathElements from C++, but the PathCurve class seems to be private and is only usable from within QML. Hardcoding PathCurve Elements works just fine like in every online example, but I want to dynamically modify the list of pathelements.
Any help would be appreciated very much!

Answer 1

You must dynamically components using the function createQmlObject, but for this you must bear in mind that it depends on the zoomLevel that you apply to the MapQuickItem the relation of sizes since that depends on the painting, the PathCurve does not use coordinates of the window but the coordinates of the Shape, and the Shape is painted according to how it is configured. So for in this case the zoomLevel of the MapQuickItem must be 0 or the same as the map. Considering the above, the solution is:
import QtQuick 2.9
import QtQuick.Window 2.2
import QtQuick.Shapes 1.12
import QtPositioning 5.9
import QtLocation 5.3
Window {
id: root
visible: true
width: 640
height: 480
title: qsTr("Hello World")
Plugin {
id: mapPlugin
name: "osm" // "mapboxgl" "osm" "esri"
}
Map {
id: map
anchors.fill: parent
plugin: mapPlugin
zoomLevel: 14
center: QtPositioning.coordinate(59.91, 10.75) // Oslo
MapQuickItem {
id: map_item
coordinate: QtPositioning.coordinate(59.91, 10.75)
anchorPoint.x : 0
anchorPoint.y : 0
zoomLevel: map.zoomLevel
sourceItem: Shape {
id: myShape
anchors.fill: parent
vendorExtensionsEnabled: false
ShapePath {
id: myPath
strokeColor: "black"
strokeWidth: 2
capStyle: ShapePath.RoundCap
fillColor: "transparent"
startX: 0; startY: 0
}
}
}
}
MouseArea {
id: mousearea
anchors.fill: map
onClicked: {
var item_pos = map.fromCoordinate(map_item.coordinate, false)
var pathcurve = Qt.createQmlObject('import QtQuick 2.12; PathCurve {}',
myPath);
pathcurve.x = mouse.x - item_pos.x
pathcurve.y = mouse.y - item_pos.y
myPath.pathElements.push(pathcurve)
}
}
}