Override QQuickImageProvider requestImage() - c++

Question

I am using QQuickImageProvider and have taken a class object(PageBuffer) in requestimage function:
class ImageProvider : public QQuickImageProvider{
public:
explicit ImageProvider();
virtual QImage requestImage(int id, QSize *size, const QSize& requestedSize,PageBuffer p);
~ImageProvider();
};
I want to set QImage of ImageProvider using the variable saved in the PageBuffer object and use the id as index
Something like this:
QImage ImageProvider:: requestImage(int id, QSize *size, const QSize &requestedSize,PageBuffer p) {
return p.imagelist[id];
}
Here is my QML file where i want to call the Image Provider:
Image{
x: 4
y: 4
height : imagerec.height
visible: true
width : imagerec.width
anchors.fill: imagerec
source:fileUrl
Text{
id:txt
x: 0
y: 71
text:"Sketch"+(index+1)
horizontalAlignment: txt.AlignHCenter
font.family: "Tahoma"
color:"#ffffff"
}
MouseArea {
anchors.rightMargin: -59
anchors.bottomMargin: -39
anchors.fill: parent
onClicked: {
p.index=index;
p.image=mod.get(index).fileUrl
main.source="image://image/"+index
}
}
}

Answer 1

Ok guys, you can begin from this example by Qt.
Also below the piece of code demonstrates using Image Provider to load random images from Internet, although I think that it is very trivial.
myimageprovider.h
class MyImageProvider : public QQuickImageProvider
{
public:
MyImageProvider(ImageType type, Flags flags = 0);
~MyImageProvider();
QImage requestImage(const QString & id, QSize * size, const QSize & requestedSize);
protected:
QNetworkAccessManager *manager;
};
myimageprovider.cpp
MyImageProvider::MyImageProvider(ImageType type, Flags flags) :
QQuickImageProvider(type,flags)
{
manager = new QNetworkAccessManager;
}
MyImageProvider::~MyImageProvider()
{
delete manager;
}
QImage MyImageProvider::requestImage(const QString &id, QSize *size, const QSize &requestedSize)
{
QUrl url("http://lorempixel.com/" + id);
QNetworkReply* reply = manager->get(QNetworkRequest(url));
QEventLoop eventLoop;
QObject::connect(reply, SIGNAL(finished()), &eventLoop, SLOT(quit()));
eventLoop.exec();
if (reply->error() != QNetworkReply::NoError)
return QImage();
QImage image = QImage::fromData(reply->readAll());
size->setWidth(image.width());
size->setHeight(image.height());
return image;
}
Registering our image provider in main.cpp:
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
MyImageProvider *imageProvider = new MyImageProvider(QQmlImageProviderBase::Image);
engine.addImageProvider("myprovider",imageProvider);
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
return app.exec();
}
And finally using the provider in QML:
Window {
visible: true
width: 800
height: 600
Image {
id: img
anchors.centerIn: parent
source: "image://myprovider/500/500/"
onStatusChanged: {
if(status == Image.Ready)
indicator.running = false;
}
BusyIndicator {
id: indicator
anchors.centerIn: parent
running: false
}
MouseArea {
anchors.fill: parent
onClicked: {
indicator.running = true;
img.source = "image://myprovider/500/500/?seed=" + Math.random(1000)
}
}
}
}