Qt5 and QML: How to update QQuickPaintedItem after widget resize? - image

Question

I'll be very appreciated for help!
i created a custom object, inherited from QQuickPaintedItem and send it to QML application.
It goes well, but there is some issue.
I need to repaint scaled image every time widget changes it's own size.
But i can't get it how to make it in C++. It call's paint method only once.
Any suggestions?
Source code:
myimage.h
#ifndef MYIMAGE_H
#define MYIMAGE_H
#include <QQuickPaintedItem>
#include <QQuickItem>
#include <QPainter>
class MyImage : public QQuickPaintedItem
{
Q_OBJECT
public:
explicit MyImage(QQuickItem *parent = 0);
void paint(QPainter* painter) override;
signals:
public slots:
};
#endif // MYIMAGE_H
myimage.cpp
#include "layerimage.h"
MyImage::MyImage(QQuickItem *parent) : QQuickPaintedItem(parent)
{
setImplicitWidth(600);
setImplicitHeight(600);
}
void MyImage::paint(QPainter *painter)
{
QImage firstImage("e:/image1.png");
QImage secondImage("e:/image2.png");
secondImage = secondImage.mirrored(false, true);
firstImage = firstImage.scaled(width(), height(),Qt::KeepAspectRatio);
secondImage = secondImage.scaled(width(), height(),Qt::KeepAspectRatio);
painter->drawImage(0,0, firstImage);
painter->setOpacity(0.5);
painter->drawImage(0,0, secondImage);
}
main.cpp
#include <QApplication>
#include <QQmlApplicationEngine>
#include <QQmlContext>
#include "myimage.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QQmlApplicationEngine engine;
qmlRegisterType<MyImage>("CustomImage", 1, 0 , "MyImage");
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
return app.exec();
}
main.qml
import QtQuick 2.5
import QtQuick.Controls 1.3
import CustomImage 1.0
ApplicationWindow {
visible: true
width: 900
height: 900
minimumWidth: 900
minimumHeight: 480
title: qsTr("Checker")
Rectangle
{
id: image
color: "transparent"
border.color: "red"
anchors
{
margins: 20
centerIn: parent
fill: parent
}
MyImage
{
anchors
{
centerIn: parent
}
}
}
}

Answer 1

Okey. I have found a solution. Seems like i need make MyImage element anchors.fill: parent. Or set width and height equal to parents size.
After that it will call paint every resize window moment!