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How to apply antialiasing to shrunk QImage on OpenGLSurface(Windows Desktop and WinRT)

  • I'm trying to draw the png image to QWindow::OpenGLSurface .

    When the app is Qt 5.4.1 for MSVC2013 or Windows Runtime, a shrunk QImage is not applied an antialiasing. On the other hand, scaled up QImage is antialiased at the same program. Is this issue solvable by a high-level API?

    QOpenGLPaintDevice device(this->size());
    QPainter painter;
    painter.setRenderHints(QPainter::HighQualityAntialiasing | QPainter::SmoothPixmapTransform, true);
    painter.drawImage(QRect(0,0,100,100), qimg); //Size of qimg is larger than (100, 100)