(solved) Screenshot in qml

[daljit97]

Hello, i'm new to qt and i'm trying to experiment screen capturing in qml, but i'm getting many errors. Can anyone help? Here's the code.
Update: I've correct some errors but doesn't work yet.
Main.cpp

@#include <QtGui/QApplication>
#include "qmlapplicationviewer.h"
#include "QPixmap"
#include "QDeclarativeView"
#include "QDeclarativeContext"
class Snap : public QObject
{
Q_OBJECT
public:
Q_INVOKABLE void shoot() {
QPixmap screenShot;
QPainter p(&screenShot);
[view]->render(&p);
}
};
int main(int argc, char *argv[]) {
QApplication app(argc, argv);

     QDeclarativeView view;

     Snap data;
     view.rootContext()->setContextProperty("snap", &data);

     view.setSource(QUrl::fromLocalFile("main.qml");
     view.show();

     return app.exec();
 }@

main.qml

@import QtQuick 1.1
import com.nokia.symbian 1.1

Page {
id: mainPage
Button {
id: button1
x: 119
y: 187
text: "Button"
onClicked: snap.shoot()
}
}@

[sierdzio]

[quote author="daljit97" date="1339960006"]but i'm getting many errors.[/quote]

Any news on what the errors actually are?

[sierdzio]

Line 11. is very, very strange. Why do you pass the QDeclarativeView to ::grabWidget()? Should it not be a real object? And why do you return QPixMap and then not do anything with it (line 11 of QML file)?

[Peppy]

@bool QPixmap::save(QString file);@ returns bool, not QPixmap.

[daljit97]

Thanks. I have done many errors because i'm new to c++ and qt. I've tried Peppy code but it anyhow shows these errors: invalid use of QPixmap::save; expected primary expressions before 'bool'.

[Peppy]

I would suggest you to look firstly at pure C++ basics of OOP, because this is not good way how to teach you, how to use C++ neither Qt/QML...

We could teach you here basics of language C++, but it's not good idea, because there are tons of tutorials and basics of C++ on the Internet...you should google it first.

I think, tutorials will be better than "try and hope" programming.

The whole function written above is logically wrong... that's all what I would say to that. And to that error. You can not use QDeclarativeView as stand-alone name for something - that's the reason why it was expecting something more (name of variable) - that is one of the basics for C++.

Best regards,
Peppy.

[daljit97]

I was trying it because i need it in qml app, but thanks anyhow.

[daljit97]

--Update: I’ve corrected some errors but doesn’t work yet.

[Peppy]

how does it look like after you have rewritten it?

[DigitalPioneer]

I wrote a class to acquire a screenshot in QML once. It's designed for QtQuick 1.1, I haven't updated it for 2.0. Here's the code:

screensnapper.h
@
#ifndef SCREENSNAPPER_H
#define SCREENSNAPPER_H

#include <QDeclarativeImageProvider>

class ScreenSnapper : public QDeclarativeImageProvider
{
public:
ScreenSnapper();

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

};

#endif // SCREENSNAPPER_H
@

screensnapper.cpp
@

#include "screensnapper.h"

#include "QApplication"
#include "QDesktopWidget"

ScreenSnapper::ScreenSnapper()
: QDeclarativeImageProvider(QDeclarativeImageProvider::Pixmap)
{
}

QPixmap ScreenSnapper::requestPixmap(const QString &id, QSize *size, const QSize &requestedSize)
{
*size = QApplication::desktop()->size();
return QPixmap::grabWindow(QApplication::desktop()->winId());
}
@

Use it in QML like so:
@
Image {
id: desktopSnapshot
source: "image://snapper/snapshot"
anchors.fill: parent
}
@

See how that does for you. :)

EDIT: Oops, I forgot the code to register it... Assuming your QDeclarativeView is called view, you'll need to do this before you load the QML:
@view->engine()->addImageProvider(QString("snapper"), new ScreenSnapper());@

[daljit97]

thank you very much, but i'm getting this little error(I'm getting errors and errors also with little things these days): base operand of '->' has non-pointer type 'QDeclarativeView'
Here's code.

@#include <QtGui/QApplication>
#include "qmlapplicationviewer.h"
#include "screensnapper.h"
Q_DECL_EXPORT int main(int argc, char *argv[])
{
QScopedPointer<QApplication> app(createApplication(argc, argv));

QmlApplicationViewer viewer;
viewer.setMainQmlFile(QLatin1String("qml/untitled18/main.qml"));
viewer.showExpanded();
QDeclarativeView view;
view->engine()->addImageProvider(QString("snapper"), new ScreenSnapper());
return app->exec();

}@

[DigitalPioneer]

OK, that's not going to work; you're creating a worthless QDeclarativeView. You need to get the engine from the actual QML viewer and set the image provider before loading the QML, like so:

@
#include <QtGui/QApplication>
#include "qmlapplicationviewer.h"
#include "screensnapper.h"
Q_DECL_EXPORT int main(int argc, char *argv[])
{
QScopedPointer<QApplication> app(createApplication(argc, argv));

QmlApplicationViewer viewer;
viewer.engine()->addImageProvider(QString("snapper"), new ScreenSnapper());
viewer.setMainQmlFile(QLatin1String("qml/untitled18/main.qml"));
viewer.showExpanded();

return app->exec();

}
@

The error you received was simply pointing out that you were using the dereferencing member selection operator (->) when you didn't have a pointer to an object, you just had the object. In that case, you would need to use the normal member selection operator, which is a dot.

[daljit97]

I've already tried it before your post but it was showing this errors(it's a malediction): -invalid use of incomplete type 'structQDeclarativeEngine'(line 9) & -forward declaration of 'structQDeclarativeEngine'

[DigitalPioneer]

Now it's angry because the compiler doesn't actually know what QDeclarativeEngine is -- you need to include the header for it:

@#include <QDeclarativeEngine>@

[daljit97]

Error: QML Image: Failed to get image from provider: image://snapper/snapshot.
P.S. : thanks to be so patient.
EDIT: It works perfectly on a symbian phone. It doesn't work in Qtsimulator.

[daljit97]

Any way to save it to the phone memory?

[DigitalPioneer]

You can look into the QtMobility stuff, but I would just write that in C++ personally.

[Djay96]

this is simple code from which i get snapshot

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

QDeclarativeView *view = new QDeclarativeView();

view->setSource(QUrl::fromLocalFile("inputQMLFile.qml")); //inputQMLFile.qml instead your QML file that will generate Image

QPixmap::grabWidget(view).save("outputFile.png"); //Output file where you want to store the image
}