[Qt-interest] transparent widget can't have parent widget

[cheng long]

Denis, I tried to fill the QWinWidget's background color by setting
QPalette's color, the background became black instead of transparent. I also
tried QWinWidget::setStyleSheet(), background became black too.

You said "As far as I know, attribute Qt::WA_TranslucentBackground is
applicable to the top-level widget only (i.e. without parent)", isn't there
any workaround to assign a parent to it?

Thanks,
Kevin

On Wed, May 19, 2010 at 8:16 PM, Denis Akhmetzyanov <
dakhmetzyanov at smartlabs.tv> wrote:

> If I used pure QtGui I would simply fill widget with transparent color. But
> I don't know how it deal with MFC widgets like CView.
>
>
> 2010/5/19 cheng long <kevinclcn at gmail.com>
>
>> Thank you Denis, is there any other approaches to make a child widget
>> transparent?
>>
>> -Kevin
>>
>>
>> On Wed, May 19, 2010 at 7:04 PM, Denis Akhmetzyanov <
>> dakhmetzyanov at smartlabs.tv> wrote:
>>
>>> Hi,
>>> As far as I know, attribute Qt::WA_TranslucentBackground is applicable to
>>> the top-level widget only (i.e. without parent). The good reference for this
>>> topic is Qt Quarterly http://doc.trolltech.com/qq/
>>> *Issue 29 · Q1 2009, Translucent Widgets in Qt*
>>>
>>>
>>> 2010/5/19 cheng long <kevinclcn at gmail.com>
>>>
>>>> I created a transparent QWinWidget and set the a CView as its parent,
>>>> but the QWinWidget has an item in the task bar and it can be shown, hidden
>>>> and closed regardless of the CView.
>>>>
>>>> Environment: Qt 4.5.2, Visual Studio 2008, Windows 7,
>>>> Code:
>>>>          QWinWidget* pQWinWidget = new QWinWidget(pWnd); // pWnd is a
>>>> CView pointer
>>>>          pQWinWidget->setWindowFlags(Qt::FramelessWindowHint);
>>>>          pQWinWidget->setAttribute(Qt::WA_TranslucentBackground);
>>>>
>>>>          QHBoxLayout *pQHBoxLayout = new QHBoxLayout(pQWinWidget);
>>>>          pQHBoxLayout->setMargin(0);
>>>>
>>>>          QGraphicsScene* scene = new QGraphicsScene();
>>>>          QGraphicsView* view = new QGraphicsView(pQWinWidget);
>>>>          pQHBoxLayout->addWidget(view);
>>>>
>>>>          view->setScene(scene);
>>>>          view->setMinimumWidth(300);
>>>>          view->setMinimumHeight(300);
>>>>          view->setRenderHints(QPainter::Antialiasing |
>>>> QPainter::TextAntialiasing);
>>>>          view->setStyleSheet("background: transparent");
>>>>
>>>>          QGraphicsTextItem* text = new QGraphicsTextItem();
>>>>          scene->addItem(text);
>>>>          text->setPlainText("hello Qt!");
>>>>
>>>>          pQWinWidget->show();
>>>>
>>>> If I comment these two lines below, the QWinWidget will exist as the
>>>> CView's child.
>>>>          pQWinWidget->setWindowFlags(Qt::FramelessWindowHint);
>>>>          pQWinWidget->setAttribute(Qt::WA_TranslucentBackground);
>>>>
>>>> Any suggestions?
>>>>
>>>> Thanks,
>>>> Kevin
>>>>
>>>> _______________________________________________
>>>> Qt-interest mailing list
>>>> Qt-interest at trolltech.com
>>>> http://lists.trolltech.com/mailman/listinfo/qt-interest
>>>>
>>>>
>>>
>>>
>>> --
>>> Best regards,
>>> Denis Akhmetzyanov
>>>
>>
>>
>
>
> --
> Best regards,
> Denis Akhmetzyanov
>
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