How to display a QPixmap/QImage in QML?

KroMignon

@Wieland Thanks a lot for your code example. This was very interresting, but still to much overhead for my very simple use case!

I found an alternative solution, which works fine for me. I post it as reply to my question if someone else has the same needs.
To pass the QImage to QML, I simply serialize into a QByteArray like this:


Q_PROPERTY(QString picture READ picture CONSTANT)

...

const QString MyImageClasse::picture()
{
   QImage myImage;
  // Some init code to setup the image (e.g. loading a PGN/JPEG, etc.)
  QByteArray bArray;
  QBuffer buffer(&bArray);
  buffer.open(QIODevice::WriteOnly);
  myImage.save(&buffer, "JPEG");

  QString image("data:image/jpg;base64,");
  image.append(QString::fromLatin1(bArray.toBase64().data()));

  return image;
}

...

Works for me (TM) ;-)

Regards

Julian Guarin

@Wieland said in How to display a QPixmap/QImage in QML?:

qmlRegisterType<PixmapContainer>("io.qt.forum", 1, 0, "PixmapContainer");
qmlRegisterType<Backend>("io.qt.forum", 1, 0, "Backend");
qmlRegisterType<PixmapImage>("io.qt.forum", 1, 0, "PixmapImage");

@Wieland Why did you register the backend & container objects? Why would you access such objects in the QML? Just being curious...

? Offline

@Julian-Guarin You're right, registering those wasn't necessary here.

Mickey Rockman

This is a very good example. I follow the code and it works exactly as I expected.
Thank you so much

Yunus

Hi, I just copied this example but I got some errors. in "backend.cpp" and "pixmapimage.cpp" . The errors are the same and:

error: undefined reference to `PixmapContainer::PixmapContainer(QObject*)'

What is the problem?

jsulm

@yunus said in How to display a QPixmap/QImage in QML?:

What is the problem?

The problem is right there in the error message.
Where is PixmapContainer::PixmapContainer(QObject*) defined?
I guess you forgot to add the cpp file for PixmapContainer.

Or change this line

explicit PixmapContainer(QObject *parent = 0);

to

explicit PixmapContainer(QObject *parent = 0) : QObject(parent) {}

Yunus

@jsulm yes I didnt add it because in the example there is no file named as pixmapcontainer.cpp

Yunus

@jsulm Ahh okey. After added the line you advised it worked thak you so much

Huang Zhen

@KroMignon It works, thank you!

fcarney

@KroMignon said in How to display a QPixmap/QImage in QML?:

I found an alternative solution

So are you feeding that string to the "source" property of QML Image?

KroMignon

@fcarney said in How to display a QPixmap/QImage in QML?:

So are you feeding that string to the "source" property of QML Image?

Yes

JoeMaesai

Thank a lot for your code example. Really appreciate.