[Interest] How to have partially transparent widget on top that do not catch events

[Frederik Christiani]

Hi,

On 13-06-2018 09:26, Nicolas Krieger wrote:
> I would like to have a border in my widget, just like a QFrame. But a 
> QFrame which border is over and not beside. I want to hide and show the 
> border, but without layout re-sizing effects.

If I understand your problem correctly, you should be able to use a 
QGraphicsEffect like this:

#include <QGraphicsEffect>
#include <QPainter>

class InsideBorderGraphicsEffect : public QGraphicsEffect
{
   Q_OBJECT
public:
   InsideBorderGraphicsEffect(QObject* parent = nullptr)
     : QGraphicsEffect(parent)
   {
   }

protected:
   void draw(QPainter* painter) override
   {
     QPoint offset;
     const QPixmap pixmap = sourcePixmap(Qt::LogicalCoordinates,
                                         &offset);
     painter->drawPixmap(offset, pixmap);
     painter->setPen(QPen(Qt::magenta, 10));
     painter->drawRect(boundingRect());
   }
};


Now it is just a matter of setting the effect on your widget with

   setGraphicsEffect(new InsideBorderGraphicsEffect);

and clear it again with

   setGraphicsEffect(nullptr);

-- 
Frederik Christiani
Viking Software
https://www.vikingsoftware.com/