Size QGraphicsView automatically

[AlvaroS]

Hi users!!
First of all thanks for helping me.

I have a Scene in a GraphicView. In this Scene I depict lines which show a map.
The problem is that the lines has not always the same size so I depict the lines sometimes small, sometimes big...
I need to fit the map to the QGraphicsView window.

Here my code is:

QGraphicsScene *scene;
QGraphicsLineItem *line;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
   scene = new QGraphicsScene(this);
    ui->graphicsView->setScene(scene); //We associate the ui GraphicsView to Scene that we have created before.

    //connect(this,SIGNAL(print_lines_signal(QFile *)),this,SLOT(print_lines_slot(QFile *)));
}

..........


        if(file.open(QFile::ReadOnly))
        {

            /*************************
             pinta las líneas
            *************************/
                QString text = file.readAll(); //Conversion from QFile to QString to be able to split the whole text in lines and words.
                QStringList lines = text.split("\n", QString::SkipEmptyParts); //Split the whole text in lines and save them in an List called "lines"
                QStringList words; //Words will save all the words in each lines. We will always have   words (x_start, y_start, x_end, y_end, psi, r)

                int num_lines = lines.size(); //We obtein the number of lines that text has.

                struct struc_lines lines_struct[num_lines]; //We create the line structury which will be an array structure with num_lines elements.

                for (int i=0;i<num_lines;i++)
                {
                    words = lines.at(i).split(" ", QString::SkipEmptyParts); // Split each line in words
                    lines_struct[i].x_start= words.at(0).toDouble(); //We take the first word and convert it to Double because it was QString type before
                    lines_struct[i].y_start= words.at(1).toDouble(); //Second word
                    lines_struct[i].x_end= words.at(2).toDouble(); //Third word
                    lines_struct[i].y_end= words.at(3).toDouble(); //Fourth word

                    QPen blue(Qt::blue);
                    blue.setWidth(1);
                    line = scene->addLine(lines_struct[i].x_start,lines_struct[i].y_start,lines_struct[i].x_end,lines_struct[i].y_end, blue); //Esta multiplicado por diez para que se vea mejor

                    std::cout<<i << " " << lines_struct[i].x_start<< std::endl;
                }
    }
 
Can anybody help me'
Thanks

[AlvaroS]

@AlvaroS I have done this:

ui->graphicsView->scale(ui->graphicsView->width()/scene->width(),ui->graphicsView->height()/scene->height());

the problem is that the scene fits well but not at all. My graphivsView always show a little scrollbars to see the part of the scene that is not showed in the graphicsview...

How can I fix that¿

Thanks.

[Joel Bodenmann]

You might want to have a look at QGraphicsView::setFixedSize(). Also, it's possible to disable the scroll bars using QGraphicsView::setXxxScrollBarPolicy()

view->setFixedSize(view->scene()->width(), view->scene()->height());
view->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
view->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

Depending on your needs, you might want to combine that together with QGraphicsView::setFixedSize().
Other functions that might help to archive what you want include QGraphicsView::ensureVisible() and QGraphicsView::fitInView().

I hope that helps

[AlvaroS]

@Joel-Bodenmann Thanks a lot. You helped me!!!