I did sub-classing to include mouse click function. Here, a rectangle can be chosen by mousePressEvent, mouseMoveEvent and mouseReleaseEvent. When I am trying to chose another rectangle, my previous rectangle is not being removed. It is still displaying with my previous drawn rectangle, which I don't want to display. I want to chose and display only one rectangle. I meant when I press again to chose another rectange, the previous one should be removed.
I included here my subclass named mouse_crop
mouse_crop.h is as follows
#ifndef MOUSE_CROP_H
#define MOUSE_CROP_H
#include <QMainWindow>
#include <QObject>
#include <QWidget>
#include <QMouseEvent>
#include <QLabel>
#include <QRubberBand>
class mouse_crop : public QLabel
{
Q_OBJECT
public:
mouse_crop(QWidget *parent=0);
QRubberBand *rubberBand;
QPoint origin, ending;
protected:
void mousePressEvent(QMouseEvent *ev);
void mouseMoveEvent(QMouseEvent *ev);
void mouseReleaseEvent(QMouseEvent *ev);
signals:
void sendMousePosition(QPoint&);
void sendMouseEnding(QPoint&);
};
#endif // MOUSE_CROP_H`
And mouse_crop.cpp is as follows
#include "mouse_crop.h"
mouse_crop::mouse_crop(QWidget *parent):QLabel (parent)
{
}
void mouse_crop::mousePressEvent(QMouseEvent *ev)
{
origin = ev->pos();
rubberBand = new QRubberBand(QRubberBand::Rectangle, this);
if(ev->button()== Qt::LeftButton || ev->button()== Qt::RightButton)
{
rubberBand->show();
emit sendMousePosition(origin);
}
}
void mouse_crop::mouseMoveEvent(QMouseEvent *ev)
{
rubberBand->setGeometry(QRect(origin, ev->pos()).normalized());
}
void mouse_crop::mouseReleaseEvent(QMouseEvent *ev)
{
ending = ev->globalPos();
if(ev->button()== Qt::LeftButton || ev->button()== Qt::RightButton)
{
emit sendMouseEnding(ending);
}
}
Can any one tell me how to solve this? Thanks in advance.
The problem is caused because every time you press the mouse you are creating a new QRubberBand, what you must do is create only a QRubberBand, hide it and show it when necessary.
mouse_crop::mouse_crop(QWidget *parent)
: QLabel(parent)
{
rubberBand = new QRubberBand(QRubberBand::Rectangle, this);
rubberBand->hide();
}
void mouse_crop::mousePressEvent(QMouseEvent *ev)
{
origin = ev->pos();
rubberBand->setGeometry(QRect(origin, origin));
if(ev->button()== Qt::LeftButton || ev->button()== Qt::RightButton)
{
rubberBand->show();
emit sendMousePosition(origin);
}
}
void mouse_crop::mouseMoveEvent(QMouseEvent *ev)
{
rubberBand->setGeometry(QRect(origin, ev->pos()).normalized());
}
void mouse_crop::mouseReleaseEvent(QMouseEvent *ev)
{
ending = ev->globalPos();
if(ev->button()== Qt::LeftButton || ev->button()== Qt::RightButton)
{
emit sendMouseEnding(ending);
}
}
Related
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;
}
}
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);
}
}
I want to select an area on a custom video widget and draw rectangle on selected area.
So far I can select an area with QRubberband but I am having trouble with drawing the rectangle after releasing left click.
Whenever I click-drag then release to draw rectangle it gives this error:
QBackingStore::endPaint() called with active painter on backingstore paint device
The program has unexpectedly finished.
Here is my code:
myvideoobject.h
#ifndef MYVIDEOOBJECT_H
#define MYVIDEOOBJECT_H
#include <QObject>
#include <QVideoWidget>
#include <QRubberBand>
#include <QPainter>
#include <QPen>
#include <QPaintEvent>
#include <QRect>
#include <QMouseEvent>
#include <QDebug>
class MyVideoObject : public QVideoWidget
{
Q_OBJECT
public:
explicit MyVideoObject(QWidget *parent = 0);
void mouseMoveEvent(QMouseEvent *ev);
void mousePressEvent(QMouseEvent *ev);
void mouseReleaseEvent(QMouseEvent *ev);
void paintEvent(QPaintEvent *ev);
private:
QRubberBand* rubberBand;
QPainter* painter;
//QRect *rectangle;
QPoint origin;
QPoint endPoint;
};
#endif // MYVIDEOOBJECT_H
myvideoobject.cpp
#include "myvideoobject.h"
MyVideoObject::MyVideoObject(QWidget* parent) :
QVideoWidget(parent)
{
rubberBand = new QRubberBand(QRubberBand::Rectangle, this);
rubberBand->setGeometry(0,0,50,50);//ileride silebilrisin
}
void MyVideoObject::mouseMoveEvent(QMouseEvent *ev)
{
rubberBand->setGeometry(QRect(origin,ev->pos()).normalized());
}
void MyVideoObject::mousePressEvent(QMouseEvent *ev)
{
origin = ev->pos();
if(!rubberBand)
rubberBand = new QRubberBand(QRubberBand::Rectangle, this);
rubberBand->setGeometry(QRect(origin,QSize()));
rubberBand->show();
}
void MyVideoObject::mouseReleaseEvent(QMouseEvent *ev)
{
rubberBand->hide();
endPoint = ev->pos();
painter->begin(this);
painter->drawRect(QRect(origin,endPoint));
}
void MyVideoObject::paintEvent(QPaintEvent *ev)
{
QRect rect = ev->rect();
painter = new QPainter(this);
painter->setRenderHint(QPainter::Antialiasing);
painter->setPen(Qt::black);
painter->drawText(rect,Qt::AlignCenter,"Data");
painter->drawRect(rect);
//painter->setPen(Qt::red);
}
I didn't add mainwindow.cpp and mainwindow.h cuz there isn't much code in those other than selecting video with openfiledialog.
When you create a pointer: QPainter *painter, this can point to any memory since it has garbage. so when you do painter->begin(this) you are accessing uninitialized memory, that's why you get that error. On the other hand in a QWidget such as QVideoWidget should only be painted in the method paintEvent, the strategy is to have variables that save the state of what you want to paint, for example the QRect, and call update to paint it.
myvideoobject.h
#ifndef MYVIDEOOBJECT_H
#define MYVIDEOOBJECT_H
#include <QVideoWidget>
class QRubberBand;
class MyVideoObject : public QVideoWidget
{
public:
MyVideoObject(QWidget *parent = nullptr);
protected:
void mouseMoveEvent(QMouseEvent *ev);
void mousePressEvent(QMouseEvent *ev);
void mouseReleaseEvent(QMouseEvent *ev);
void paintEvent(QPaintEvent *ev);
private:
QRubberBand *rubberBand;
QPoint origin;
QRect rect;
};
#endif // MYVIDEOOBJECT_H
myvideoobject.cpp
#include "myvideoobject.h"
#include <QMouseEvent>
#include <QPainter>
#include <QRubberBand>
MyVideoObject::MyVideoObject(QWidget *parent):
QVideoWidget(parent),
rubberBand(nullptr){}
void MyVideoObject::mousePressEvent(QMouseEvent *ev)
{
origin = ev->pos();
if(!rubberBand)
rubberBand = new QRubberBand(QRubberBand::Rectangle, this);
rubberBand->setGeometry(QRect(origin,QSize()));
rubberBand->show();
QVideoWidget::mousePressEvent(ev);
}
void MyVideoObject::mouseMoveEvent(QMouseEvent *ev)
{
rubberBand->setGeometry(QRect(origin,ev->pos()).normalized());
QVideoWidget::mouseMoveEvent(ev);
}
void MyVideoObject::mouseReleaseEvent(QMouseEvent *ev)
{
rect = rubberBand->geometry();
update();
QVideoWidget::mouseReleaseEvent(ev);
}
void MyVideoObject::paintEvent(QPaintEvent *ev)
{
QVideoWidget::paintEvent(ev);
QPainter painter(this);
painter.save();
painter.setBrush(Qt::red);
if(!rect.isNull())
painter.drawRect(rect);
painter.restore();
}
I am new in qt and c++. I have a qgraphicsview to plot signal. I would zoom specific area with mouse clicking and rectangle drawing. So I need mouse pressed position and dragged position. For this I do such this:
in header file:
#include <QtWidgets/QMainWindow>
#include <QGraphicsScene>
#include <QMouseEvent>
#include <QGraphicsSceneMouseEvent>
#include "ui_QtGuiApplication.h"
class QtGuiApplication : public QMainWindow
{
Q_OBJECT
public:
QtGuiApplication(QWidget *parent = Q_NULLPTR);
protected:
void mouseMoveEvent(QMouseEvent* event);
void mousePressEvent(QMouseEvent* event);
bool eventFilter(QObject *obj, QEvent *ev);
private:
Ui::QtGuiApplicationClass ui;
QPoint Zoom_point1_;
QPoint Zoom_point2_;
QGraphicsScene* scene = new QGraphicsScene();
};
in source file:
QtGuiApplication::QtGuiApplication(QWidget *parent)
: QMainWindow(parent)
{
ui.setupUi(this);
ui.graphicsView->installEventFilter(this);
ui.graphicsView->setMouseTracking(true);
}
bool QtGuiApplication::eventFilter(QObject * obj, QEvent * ev)
{
if (obj == ui.graphicsView)
if (ev->type() == QEvent::MouseMove)
{
QMouseEvent *mEvent = (QMouseEvent*)ev;
Zoom_point2_ = mEvent->pos();
}
return false;
}
void QtGuiApplication::mouseMoveEvent(QMouseEvent * ev)
{
Zoom_point2_ = ev->globalPos();
//do some thing …
}
void QtGuiApplication::mousePressEvent(QMouseEvent * ev)
{
Zoom_point1_ = ev->globalPos();
}
When I press and move mouse in graphicsview, I can recognize the clicked position but mouseMoveEvent(QMouseEvent * ev) never be calle. and also obj == ui.graphicsView statement in eventFilter never be occurred.What's wrong with me? How can I fix it?
By Installing event filter on the viewport of the QgraphicsView object such as
ui.graphicsView->viewport()->installEventFilter(this);
and adding below condition on eventfilter
if (ui.graphicsView->viewport())
if (ev->type() == QEvent::MouseMove)
{
QMouseEvent *mEvent = (QMouseEvent*)ev;
Zoom_point2_ = mEvent->pos();
}
problem solved.
I am trying to get a mouse press event to work with my widget I created but every time I click the widget, the window stops responding and I have to kill the program. Does anyone know how to fix this and also how to get the color to change?
Here is the .h and the .cpp files.
.cpp file:
#include "iconwidget.h"
#include <QPaintEvent>
#include <QPainter>
#include <QPainterPath>
iconWidget::iconWidget(QWidget *parent) :
QWidget(parent)
{
this->resize(ICON_WIDGET_WIDTH,ICON_WIDGET_HEIGHT);
pressed = false;
}
void iconWidget::paintEvent(QPaintEvent *event)
{
QRect areatopaint = event->rect();
QPainter painter(this);
QBrush brush(Qt::black);
QPointF center = this->rect().center();
QPainterPath icon;
icon.addEllipse(center,20,20);
painter.drawPath(icon);
painter.fillPath(icon, brush);
if (pressed) {
brush.setColor(Qt::red);
}
}
void iconWidget::mousePressEvent(QMouseEvent *event)
{
pressed = true;
update();
iconWidget::mousePressEvent(event);
}
.h file:
#define ICONWIDGET_H
#include <QWidget>
#define ICON_WIDGET_WIDTH 45
#define ICON_WIDGET_HEIGHT 45
class iconWidget : public QWidget
{
Q_OBJECT
public:
explicit iconWidget(QWidget *parent = 0);
void paintEvent(QPaintEvent *event);
bool pressed;
protected:
void mousePressEvent(QMouseEvent *event);
};
#endif // ICONWIDGET_H
You call mousePressEvent() in an endless recursion. You should change the line:
iconWidget::mousePressEvent(event);
in your mousePressEvent function to:
QWidget::mousePressEvent(event);
I have a window based on a semitransparent image:
import QtQuick 1.1
import QtWebKit 1.1
Image {
source: "qrc:/assets/bg.png"
}
And something like this in main window
#include "mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent)
{
setAttribute(Qt::WA_TranslucentBackground);
setStyleSheet("background:transparent;");
/* turn off window decorations */
setWindowFlags(Qt::FramelessWindowHint);
ui = new QDeclarativeView;
ui->setSource(QUrl("qrc:/assets/ui.qml"));\
setCentralWidget(ui);
}
MainWindow::~MainWindow()
{
delete ui;
}
and
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QtDeclarative/QDeclarativeView>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
QDeclarativeView *ui;
};
#endif // MAINWINDOW_H
I wonder how to make my window draggable across the screen (user presses on an image and drugs window around..)?
Reimplement mousePressEvent() and mouseReleaseEvent() to know when the user is holding the mouse down, then reimplement mouseMoveEvent() and if the user is holding the mouse down, move the widget.
// **Untested code**
protected:
virtual void mousePressEvent(QMouseEvent *event) { _mouseIsDown = true; }
virtual void mouseReleaseEvent(QMouseEvent *event) { _mouseIsDown = false; }
virtual void mouseMoveEvent(QMouseEvent *event) { if(_mouseIsDown) { move(event->pos() + globalPos()); } }
#include <QMouseEvent>
#include <Qpoint>
class MainWindow : public QMainWindow{
...
void mousePressEvent(QMouseEvent *event);
void mouseMoveEvent(QMouseEvent *event);
QPoint LastPoint;
QPoint LastTopLeft;
void mousePressEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton) {
QPoint Point=event->globalPos();
LastTopLeft=this->frameGeometry().topLeft();
LastPoint=Point;
}
}
void mouseMoveEvent(QMouseEvent *event)
{
if ((event->buttons() & Qt::LeftButton)) {
const QPoint Point=event->globalPos();
QPoint offset=Point-LastPoint;
this->move(LastTopLeft+offset);
}
}
...
}
It worked for me after I removed the first two declarations.