How to get global geometry of child widget - c++

Question

I have label inside custom frame.
I try to movement of MainWindow (all aplication) on mouse event:
void settingslogolabel::mouseMoveEvent(QMouseEvent *ev)
{
if ((ev->buttons() & Qt::LeftButton) && firstCIsNotNull){
window()->move( mapToGlobal(ev->pos() - m_dragPosition - this->geometry().topLeft()));
}
}
BUT! this->geometry() returns local geometry.
So, how can I get global geometry of child?
What I try to make:
When you press mouse and move - all application should move as your cursor move, until you up mouse button. I want to make this interactive for label.
Full code:
HPP:
#ifndef SETTINGSLOGOLABEL_H
#define SETTINGSLOGOLABEL_H
#include <QLabel>
#include <QWidget>
#include <QMouseEvent>
class settingslogolabel : public QLabel
{
Q_OBJECT
public:
explicit settingslogolabel(QWidget *parent = 0);
void mouseMoveEvent(QMouseEvent *ev);
void mousePressEvent(QMouseEvent *ev);
void mouseReleaseEvent(QMouseEvent *ev);
private:
QPoint m_dragPosition;
bool firstCIsNotNull = true;
private:
};
#endif // SETTINGSLOGOLABEL_H
CPP:
#include "settingslogolabel.hpp"
settingslogolabel::settingslogolabel(QWidget *parent) :
QLabel(parent)
{
}
void settingslogolabel::mouseMoveEvent(QMouseEvent *ev)
{
if ((ev->buttons() & Qt::LeftButton) && firstCIsNotNull){
window()->move( mapToGlobal(ev->pos() - m_dragPosition - this->geometry().topLeft()));
}
}
void settingslogolabel::mousePressEvent(QMouseEvent *ev)
{
if (ev->button() == Qt::LeftButton) {
m_dragPosition = ev->pos();
firstCIsNotNull = true;
}
}
void settingslogolabel::mouseReleaseEvent(QMouseEvent *ev)
{
if (ev->button() == Qt::LeftButton) {
firstCIsNotNull = false;
}
}

Answer 1

Not sure I fully understand the problem but, the global coordinates of the top left corner of a widget can be found -- from within that widget's member functions -- using...
mapToGlobal(QPoint(0, 0));
Similarly, the global geometry would be...
rect().translated(mapToGlobal(QPoint(0, 0)));
Edit:
If the aim is to allow dragging of the top level window then your mouseMoveEvent implementation should be something like (untested)...
void settingslogolabel::mouseMoveEvent (QMouseEvent *ev)
{
if ((ev->buttons() & Qt::LeftButton) && firstCIsNotNull) {
auto delta = ev->pos() - m_dragPosition;
window()->move(window()->pos() + delta);
}
}