QT Double buffering does not work on the board



  • The PC will operate normally , but the image output is not smooth in the board.
    I checked and double-buffering support in QT itself, I understand that.
    Why not apply ? Below are the specific signal occurs when the behavior of the function.

    void curvePlotter::keyPressEvent(QKeyEvent *event)
    {

    switch (event->key()) {
    case Qt::Key_Plus:
        zoomIn();
        break;
    case Qt::Key_Minus:
        zoomOut();
        break;
    case Qt::Key_Left:
        zoomStack[curZoom].scroll(-1, 0);
        refreshPixmap();
        break;
    case Qt::Key_Right:
        zoomStack[curZoom].scroll(+1, 0);
        refreshPixmap();
        break;
    case Qt::Key_Down:
        zoomStack[curZoom].scroll(0, -1);
        refreshPixmap();
        break;
    case Qt::Key_Up:
        zoomStack[curZoom].scroll(0, +1);
        refreshPixmap();
        break;
    default:
        QWidget::keyPressEvent(event);
    }
    

    }

    void curvePlotter::refreshPixmap()
    {
    pixmap = QPixmap(size());
    pixmap.fill(this, 0, 0);
    QPainter painter(&pixmap);
    painter.initFrom(this);
    drawGrid(&painter);
    drawCurves(&painter);
    update();
    }


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