[Qt-interest] Making part of QWebView as transaparent

[Nitin Mahajan]

Hello,

--- On Wed, 16/12/09, Samuel Rødal <sroedal at trolltech.com> wrote:

> From: Samuel Rødal <sroedal at trolltech.com>
> Subject: Re: [Qt-interest] Making part of QWebView as transaparent
> To: nitinm76 at yahoo.com
> Cc: qt-interest at trolltech.com
> Date: Wednesday, 16 December, 2009, 2:20 PM
> Nitin Mahajan wrote:
> > HI,
> > 
> > --- On Tue, 15/12/09, Samuel Rødal <sroedal at trolltech.com>
> wrote:
> > 
> >> From: Samuel Rødal <sroedal at trolltech.com>
> >> Subject: Re: [Qt-interest] Making part of QWebView
> as transaparent
> >> To: nitinm76 at yahoo.com
> >> Cc: qt-interest at trolltech.com
> >> Date: Tuesday, 15 December, 2009, 6:23 PM
> >> Nitin Mahajan wrote:
> >>> Hello,
> >>> 
> >>> I am trying to make a part of QWebView as
> transparent
> >> using setMask(). I am doing this experiment with
> the demo
> >> browser.
> >>> The demo browser is allowed to run for some
> time.Later
> >> some region of web view is made transparent using
> setMask().
> >> 
> >>> What I find is that the region where a whole
> should
> >> have been punched remains white, instead of
> becoming
> >> transparent. Can some one help me with this?
> >>> regards
> >>> 
> >>> -Nitin
> >> Are you sure you're using setMask() on a top-level
> widget?
> >> Otherwise there won't be any transparency as
> there'll be
> >> another widget behind.
> >> 
> > 
> > You are right. I forgot to set mask on
> BrowserMainWindow. After doing that the transparency is
> fine. 
> > Now I have a new problem. The Area where I punch a
> hole in webview,had a child widget. That widget is also not
> being shown now. I want to show that child widget with some
> transparency.
> > 
> > Can I get, some pointers towards this?
> > 
> > regards
> > 
> > -Nitin
> 
> With setMask() you can only get either fully opaque or
> fully transparent pixels. If you want semi transparency you
> need to not use setMask() but use the window attribute
> Qt::WA_TranslucentBackground on the top level.
> 
> You then need to override the top level's paint event to
> source fill the areas where you want transparency with
> Qt::transparent, something like this:
> 
> // first let the parent do its drawing
Do you mean Base class's paintEvent() or Parent Widget's paint event?
> ParentClass::paintEvent(event);
> 
> QPainter p(this);
> p.setCompositionMode(QPainter::CompositionMode_Source);
> 
> // fill the region where you want transparency

Why the for loop here?
> foreach (QRect rect, transparentRegion);
>     p.fillRect(rect, Qt::transparent);
> 
> 
I wrote the child widget's paint event like this, and it does most of the job the way I wanted.

void MyWidget::paintEvent(QPaintEvent *event)
{
     QWidget::paintEvent(event);
     QPainter p(this);
     p.setCompositionMode(QPainter::CompositionMode_Source);
     p.fillRect(rect(), Qt::transparent);
}

Only problem is my mouse, which is a PNG image appears with a very dirty square background in the transparent area. Am I missing something here?

regards

-Nitin


--
> Samuel
> 


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