c++ - Implement Resize option to Qt Frameless widget

Question

How can i implement resize option to Qt frameless widget that it's used as Main Window?

Answer 1

I just encountered this problem as well, and I solved it by adding custom mouseEvent handlers for my QMainWindow. I'm using PyQt, but it should be fairly similar in C++.

In my implementation, dragging the right mouse button anywhere on the frameless widget (called MyClass) resizes it.

When the right mouse button is pressed, store the coordinates:

def mousePressEvent(self, event):
    super(MyClass, self).mousePressEvent(event)

    if event.button() == QtCore.Qt.RightButton:
        self.rdragx = event.x()
        self.rdragy = event.y()        
        self.currentx = self.width()
        self.currenty = self.height()
        self.rightClick = True

If the mouse is moved while the button is still pressed (i.e., when it's dragged), resize the QMainWindow. Don't allow it to become smaller than the predefined minimum size.

def mouseMoveEvent(self, event):
    super(Myclass, self).mouseMoveEvent(event)
    if self.rightClick == True:
        x = max(frame.minimumWidth(), 
                self.currentx + event.x() - self.rdragx)
        y = max(frame.minimumHeight(), 
                self.currenty + event.y() - self.rdragy)
        self.resize(x, y)

When the mouse button is released, reset the button variable to False to stop resizing on movement.

def mouseReleaseEvent(self, event):
    super(MyClass, self).mouseReleaseEvent(event)
    self.rightClick = False