problem of customize the shape of QDialog

[julianfox0119]

customDlg.PNGcustomDlg.PNG

hello everyone,

i want to customize the shape of the QDialog and found a example for test, the code is:

void customDlg::paintEvent(QPaintEvent* event)
{
    Q_UNUSED(event)
 
    QPainter painter(this);
    QStyle* style = this->style();
    QRect active_area = this->rect();
 
    qDebug() << active_area;
 
    int titlebar_height = 0;
 
    // Titlebar.
    QStyleOptionTitleBar t_opt;
    t_opt.initFrom(this);
 
    titlebar_height = style->pixelMetric(QStyle::PM_TitleBarHeight, &t_opt, this);
 
    qDebug() << titlebar_height;
 
    t_opt.rect = QRect(0, 0, this->width(), titlebar_height);
    t_opt.titleBarState = this->windowState();
    t_opt.titleBarFlags = Qt::FramelessWindowHint;
    t_opt.text = t_opt.fontMetrics.elidedText(this->windowTitle(), Qt::ElideRight, t_opt.rect.width());
    style->drawComplexControl(QStyle::CC_TitleBar, &t_opt, &painter, this);
    style->drawItemText(&painter, t_opt.rect, Qt::AlignCenter, t_opt.palette, true, t_opt.text, QPalette::ToolTipText);
 
    // Background widget.
    active_area.setTopLeft(QPoint(0, titlebar_height));
    this->setContentsMargins(0, titlebar_height, 0, 0);
 
    QStyleOption w_opt;
    w_opt.initFrom(this);
    w_opt.rect = active_area;
 
    qDebug() << w_opt.rect;
 
    style->drawPrimitive(QStyle::PE_Widget, &w_opt, &painter, this);
}

void customDlg::paintEvent(QPaintEvent* event)
{
    Q_UNUSED(event)

    QPainter painter(this);
    QStyle* style = this->style();
    QRect active_area = this->rect();

    qDebug() << active_area;

    int titlebar_height = 0;

    // Titlebar.
    QStyleOptionTitleBar t_opt;
    t_opt.initFrom(this);

    titlebar_height = style->pixelMetric(QStyle::PM_TitleBarHeight, &t_opt, this);

    qDebug() << titlebar_height;

    t_opt.rect = QRect(0, 0, this->width(), titlebar_height);
    t_opt.titleBarState = this->windowState();
    t_opt.titleBarFlags = Qt::FramelessWindowHint;
    t_opt.text = t_opt.fontMetrics.elidedText(this->windowTitle(), Qt::ElideRight, t_opt.rect.width());
    style->drawComplexControl(QStyle::CC_TitleBar, &t_opt, &painter, this);
    style->drawItemText(&painter, t_opt.rect, Qt::AlignCenter, t_opt.palette, true, t_opt.text, QPalette::ToolTipText);

    // Background widget.
    active_area.setTopLeft(QPoint(0, titlebar_height));
    this->setContentsMargins(0, titlebar_height, 0, 0);

    QStyleOption w_opt;
    w_opt.initFrom(this);
    w_opt.rect = active_area;

    qDebug() << w_opt.rect;

    style->drawPrimitive(QStyle::PE_Widget, &w_opt, &painter, this);
}

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but there is a gray rect behind the round corner of the titlebar(see attachment), how can i remove(or hide) it?
thanks!