svg background for QGraphicsView C++ - c++

Question

I would like to put an svg image as background to my QGraphicsView without repetition and preserving the ratio. Can you help me?
Thanks.

Answer 1

This is one Example :
First of all add QT += svgwidgets in your .pro.
then add one graphicsView in your UI File :
in mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QGraphicsScene>
#include <QMainWindow>
QT_BEGIN_NAMESPACE
namespace Ui
{
class MainWindow;
}
QT_END_NAMESPACE
class MainWindow: public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
private:
Ui::MainWindow *ui;
QGraphicsScene *scene;
};
#endif // MAINWINDOW_H
in mainwindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QGraphicsSvgItem>
#include <QSvgRenderer>
MainWindow::MainWindow(QWidget *parent):
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
scene = new QGraphicsScene(this);
ui->graphicsView->setScene(scene);
QGraphicsSvgItem *item = new QGraphicsSvgItem(":/images/images/diagramTool.svg");
scene->addItem(item);
}
MainWindow::~MainWindow()
{
delete ui;
}
output :
And there is one easy way you can add this stylesheet in your graphics view :
background-image: url(":/images/images/diagramTool.svg");
background-repeat: no-repeat;
background-position: center;
border-style:none;
This will add SVG as your background image.

Answer 2

To put a background that fits the size of the object I created a class that inherits from QGraphicsScene and I rewrote drawBackground by putting my svg image in it.
myscene.h
class myscene : public QGraphicsScene
{
public:
myscene();
~myscene();
void drawBackground(QPainter *painter, const QRectF &rect);
};
myscene.cpp
myscene::myscene():QGraphicsScene()
{
}
myscene::~myscene()
{
}
void myscene::drawBackground(QPainter *painter, const QRectF &rect)
{
painter->drawImage(rect, QImage(":myPathImage.svg"));
}
Then in my QGraphicsView I passed it this scene and it works.
myview.h:
class myview : public QGraphicsView
{
private :
myscene* _scene;
public:
myview();
~myview();
};
myview.cpp:
myview::myview() : QGraphicsView()
{
_scene = new myscene();
this->setScene(_scene);
this->showMaximized();
}
myview::~myview()
{
delete _scene;
}