Alpha color and irregular form widget

[sshd]

Hi, I need to write a program similar to XTeddy, portable, I make the image to be showed and I can move it with the mouse, but it appear in a rectancle that ignore the alpha color.

Some idea of how to set the region of the widget only to the non alpha zone of the image?

Thanks

PD: sorry for my bad english

[wysota]

Take a look at QWidget::setMask.

[sshd]

I have a problem again, with the function

void CarmenTiger::paintEvent(QPaintEvent *) {
   QPainter painter(this);
   QPointF  point;
   const QImage image = QImage("tiger.png");
 
   painter.setBackgroundMode(Qt::TransparentMode);
   painter.setRenderHint(QPainter::Antialiasing);
   painter.drawImage(point, image);
} // paintEvent

void CarmenTiger::paintEvent(QPaintEvent *) {
   QPainter painter(this);
   QPointF  point;
   const QImage image = QImage("tiger.png");

   painter.setBackgroundMode(Qt::TransparentMode);
   painter.setRenderHint(QPainter::Antialiasing);
   painter.drawImage(point, image);
} // paintEvent

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the program draw the image over a rectangle and using the function

void CarmenTiger::paintEvent(QPaintEvent *) {
   QLabel  topLevelLabel;
   QPixmap pixmap(":/tiger.png");
 
   topLevelLabel.setPixmap(pixmap);
   topLevelLabel.setMask(pixmap.mask());
} // paintEvent

void CarmenTiger::paintEvent(QPaintEvent *) {
   QLabel  topLevelLabel;
   QPixmap pixmap(":/tiger.png");

   topLevelLabel.setPixmap(pixmap);
   topLevelLabel.setMask(pixmap.mask());
} // paintEvent

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the program draw only the rectangle.

Any idea of what is wrong?

[jpn]

You don't want to

• instantiate a QLabel object (you create a label, set a pixmap, and the object is immediately destructed after paintEvent() reaches its end)
• apply the mask (which is an expensive operation especially if the mask is complex)

during every paint event.

[sshd]

OK, I understand the problem, but I have no idea of how fix it, what I have to modify, something in the main.cpp, the constructor, the paintEvent or I have to write another function?