[Gabor]

Hi,

In my QML app I want to use QQuickImageProvider to turn an image into QPixmap. I created the ResourceImageProvider class like this:

resourceimageprovider.h:

#ifndef RESOURCEIMAGEPROVIDER_H
#define RESOURCEIMAGEPROVIDER_H

#include <QQuickImageProvider>
#include <QImage>
#include <QPixmap>
#include <QObject>

class ResourceImageProvider : public QQuickImageProvider, public QObject
{
    Q_OBJECT
public:
    ResourceImageProvider();
//    ~ ResourceImageProvider();

    QImage requestImage(const QString &id, QSize *size, const QSize &requestedSize);
    QPixmap requestPixmap(const QString &id, QSize *size, const QSize &requestedSize);
};

#endif // RESOURCEIMAGEPROVIDER_H

resourceimageprovider.cpp:

#include "resourceimageprovider.h"


ResourceImageProvider::ResourceImageProvider() : QQuickImageProvider (QQuickImageProvider(Image))
{



}
QImage ResourceImageProvider::requestImage (const QString &id, QSize *size, const QSize &requestedSize)
{
    QString rsrcid = ":/" + id;
    QImage image(rsrcid);
    QImage result;

    if(requestedSize.isValid ()) {
        result = image.scaled (requestedSize,Qt::KeepAspectRatio);
    } else {
        result = image;
    }

    *size = result.size();
    return  result;
}

QPixmap requestPixmap(const QString &id, QSize *size, const QSize &requestedSize)
{
    QString rsrcid = ":/" + id;
    QPixmap image(rsrcid);
    QPixmap result;

    if(requestedSize.isValid ()) {
        result = image.scaled (requestedSize,Qt::KeepAspectRatio);
    } else {
        result = image;
    }

    *size = result.size();
    return  result;
}

main.cpp:

#include <QApplication>
#include <VPApplication>

#include <QQmlApplicationEngine>
#include <QQuickImageProvider>
#include "resourceimageprovider.h"


int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    VPApplication vplay;

    // Use platform-specific fonts instead of Felgo's default font
    vplay.setPreservePlatformFonts(true);

    QQmlApplicationEngine engine;
  vplay.initialize(&engine);

    // use this during development
    // for PUBLISHING, use the entry point below
    vplay.setMainQmlFileName(QStringLiteral("qml/Main.qml"));

    ResourceImageProvider *imageProvider = new ResourceImageProvider();
    imageProvider->requestPixmap("kép",140,100);
    engine.rootContext ()->setContextProperty("ImageProvider",imageProvider);

    // vplay.setMainQmlFileName(QStringLiteral("qrc:/qml/Main.qml"));

    engine.load(QUrl(vplay.mainQmlFileName()));

    return app.exec();
}

How can I fix the

 imageProvider->requestPixmap("kép",140,100);

line so I would be able to ssign values from the QML code?

(I am trying to follow the Integrate C++ and QML example).

Thank you for your help.

[Kacper]

Did you see it?

How to Expose a Qt C++ Class with Signals and Slots to QML

[Gabor Toth]

Hi,

Yes, I tried. I wanted to add the c++ object as a property. My problem is that requestPixmap needs to pass 3 variables (id, size and requested size) and I couldn’t figure out how to use those variables there.

[GüntherFelgo Team]

To make functions or properties usable from QML, your ResourceImageProvider type requires some additional markup. For example, add them under public slots, similar to the increment(value) method of the guide:  How to Expose a Qt C++ Class with Signals and Slots to QML

You can then call requestPixmap(…) on the ResourceImageProvider instance in your QML code.