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Thread: Trouble with image painting (QPainter + QImage)

  1. #1
    Join Date
    Jan 2006
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    Default Trouble with image painting (QPainter + QImage)

    Hello!

    Why this code is incorrect?
    Why image doesn't painting in frame?

    //////////////////////////////////////////////////////////////////
    #include <QtGui>
    #include <QApplication>
    int main(int argc, char *argv[])
    {
    QApplication app(argc, argv);
    QFrame f;
    QPainter p(&f);
    QImage i("tst.jpg");
    p.drawImage(0,0,i);
    f.show();
    return app.exec();
    }
    //////////////////////////////////////////////////////////////////

    P.S.
    mingw / QT-4.1.0

  2. #2
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    Default Re: Trouble with image painting (QPainter + QImage)

    Quote Originally Posted by krivenok
    Why this code is incorrect?
    Why image doesn't painting in frame?
    1. Everything you draw on a hidden widget will be discarded.
    2. Make sure you have JPEG image format plugin compiled
    3. The docs say:
      Warning: Unless a widget has the Qt::WA_PaintOutsidePaintEvent attribute set. A QPainter can only be used on a widget inside a paintEvent() or a function called by a paintEvent(). On Mac OS X, you can only paint on a widget in a paintEvent() regardless of this attribute's setting.


    If you want to show an image, use QLabel and the QLabel::setPixmap() method.

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