hi,
i have a QLabel and loaded a picture in it. Now i'd like to realize that a user can select a part of the picture. Therefore i captured the mouseevents over the label and could save the selection in another QLabel (like clipping).
So far, everything works fine, but now i want to visualize the selection the user is doing while he has pressed the mouse over the picture. I tried using a QPainter like this:
QRectF rectangle(leftUpperX, leftUpperY, rightLowerX, rightLowerY);
QPainter painter(this);
painter.drawRect(rectangle);
In the mousemove-event i got no functionality and this error:
QPainter::begin: Widget painting can only begin as a result of a paintEvent
So i tried to put in into an paint-Event:
void InitialLabel::paintEvent(QPaintEvent* event) {
QRectF rectangle(10.0, 20.0, 200.0, 200.0);
QPainter painter(this);
painter.drawRect(rectangle); // drawing code
}
But now the picture is no longer shown, only the rectangle.
What i would like is a variable rectangle while the mouse button is held that fixes it's position when the mouse button is released.
This should be on top of the picture, so that a user can see the picture in the background while he makes his selection.
Anyone who can help me with this?
Thanks in advance.
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