Stopped widget in a moveable QGraphicsScene

[jano_alex_es]

Hello,

I'm doing a game with items in a QGraphicsScene - QGraphicsView. The scene is the entire level, it's big, so the view is following the main character when it's going outside the boundaries.

But I want to have a static widget (a button) in the bottom-left part of the screen (view). So the view is focusing in the main character but that widget keeps its position on the screen.

I though I could achieve that by calculating (each frame) the QGraphicsView position in the screen and place the button in the proper scene coordinate.

So far I tried with QWidget::pos() and QGraphicsView::sceneRect() but it's no use.

How can I know the position the view is showing of the scene every frame, or, if so, there is any way to have a QGraphicsPixmap item statically in the view?

thanks!

[jano_alex_es]

So, there is no way to know which part of the QGraphicsScene is showing the QGraphicsView? (sceneRect does not work as expected, it return the whole scene)

[Stef]

If the button is supposed to be in the bottom-left position of the screen (the qgraphicsview) the whole time, then why don't you just create it on top of the qgraphicsview instead of creating it in the qgraphicsscene?

You can achieve this very easy. Assuming you have a QMainWindow with according ui class and a QGraphicsView widget (graphicsview) is placed in this form. The code look like:

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
 
namespace Ui {
    class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
    void createButton(int buttonWidth, int buttonHeight);
 
private:
    Ui::MainWindow *ui;
};
 
#endif // MAINWINDOW_H

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
    class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

    void createButton(int buttonWidth, int buttonHeight);

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

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mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
 
#include <QPushButton>
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::createButton(int buttonWidth, int buttonHeight)
{
    QPushButton* button = new QPushButton(ui->graphicsView);
    button->setText("Click me!");
 
    button->setGeometry(0,
                        ui->graphicsView->geometry().height() - buttonHeight,
                        buttonWidth, buttonHeight);
 
    button->show();
}

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QPushButton>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::createButton(int buttonWidth, int buttonHeight)
{
    QPushButton* button = new QPushButton(ui->graphicsView);
    button->setText("Click me!");

    button->setGeometry(0,
                        ui->graphicsView->geometry().height() - buttonHeight,
                        buttonWidth, buttonHeight);

    button->show();
}

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main.cpp

#include <QtGui/QApplication>
#include "mainwindow.h"
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
 
    w.createButton(100,50);
 
    return a.exec();
}

#include <QtGui/QApplication>
#include "mainwindow.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    w.createButton(100,50);

    return a.exec();
}

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[jano_alex_es]

Lol, I didn't think in that possibility... thanks!