Qt example 37: rounded rectangle item is a QGraphicsRectItem example that displays some QGraphicsRectItem the are movable and selectable. Additionally, the items display their coordinats.

Technical facts

Application type(s)

Desktop application

Operating system(s) or programming environment(s)

Lubuntu 12.10 (quantal)

IDE(s):

Qt Creator 2.5.2

Project type:

GUI application

C++ standard:

C++11

Compiler(s):

G++ 4.7.2

Libraries used:

Qt: version 4.8.3 (32 bit)
STL: GNU ISO C++ Library, version 4.7.2

Qt project file: CppQtExample37.pro


QT       += core gui

QMAKE_CXXFLAGS += -std=c++11 -Wall -Wextra -Werror

TARGET = CppQtExample37

TEMPLATE = app



SOURCES += \

    qtmain.cpp \

    qtwidget.cpp \

    qtroundedrectitem.cpp



HEADERS += \

    qtwidget.h \

    qtroundedrectitem.h

qtmain.cpp


#include <QApplication>

#include <QDesktopWidget>

#include "qtwidget.h"



int main(int argc, char *argv[])

{

  QApplication a(argc, argv);

  QtWidget w;

  {

    //Resize the dialog and put it in the screen center

    w.setGeometry(0,0,800,600);

    const QRect screen = QApplication::desktop()->screenGeometry();

    w.move( screen.center() - w.rect().center() );

  }

  w.show();

  return a.exec();

}

qtroundedrectitem.h


#ifndef QTRECTITEM_H

#define QTRECTITEM_H



#include <QGraphicsRectItem>



struct QtRoundedRectItem : public QGraphicsRectItem

{

  QtRoundedRectItem(QGraphicsItem *parent = 0, QGraphicsScene *scene = 0);



  void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);



  ///Get the rounded rect corner x radius

  double getRadiusX() const { return m_radius_x; }



  ///Get the rounded rect corner y radius

  double getRadiusY() const { return m_radius_y; }



  ///Set the rounded rect corner x radius

  void setRadiusX(const double radius_x) { m_radius_x = radius_x; }



  ///Set the rounded rect corner y radius

  void setRadiusY(const double radius_y) { m_radius_y = radius_y; }



  ///Set the rounded rect

  void setRoundedRect(const QRectF rect, const double radius_x, const double radius_y);



  private:



  ///The rounded rect corner x radius

  double m_radius_x;



  ///The rounded rect corner y radius

  double m_radius_y;

};



#endif // QTRECTITEM_H

qtroundedrectitem.cpp


#ifdef _WIN32

//See http://www.richelbilderbeek.nl/CppCompileErrorSwprintfHasNotBeenDeclared.htm

#undef __STRICT_ANSI__

#endif



//#include own header file as first substantive line of code, from:

// * John Lakos. Large-Scale C++ Software Design. 1996. ISBN: 0-201-63362-0. Section 3.2, page 110

#include "qtroundedrectitem.h"



#include <cassert>

#include <sstream>

#include <QGraphicsScene>

#include <QPainter>



QtRoundedRectItem::QtRoundedRectItem(QGraphicsItem *parent, QGraphicsScene *scene)

 : QGraphicsRectItem(parent,scene)

{

  this->setFlags(

      QGraphicsItem::ItemIsFocusable

    | QGraphicsItem::ItemIsMovable

    | QGraphicsItem::ItemIsSelectable);



}



void QtRoundedRectItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)

{

  if (this->isSelected())

  {

    QPen pen;

    pen.setStyle(Qt::DashLine);

    painter->setPen(pen);

  }

  painter->drawRoundedRect(this->rect(),m_radius_x,m_radius_y);

}



void QtRoundedRectItem::setRoundedRect(const QRectF rect, const double radius_x, const double radius_y)

{

  this->setRect(rect);

  this->setRadiusX(radius_x);

  this->setRadiusY(radius_y);

}

qtwidget.h


#ifndef QTWIDGET_H

#define QTWIDGET_H



#include <QGraphicsView>



///The widget holding the items

struct QtWidget : public QGraphicsView

{

  QtWidget(QWidget *parent = 0);

};



#endif // QTWIDGET_H

qtwidget.cpp


#ifdef _WIN32

//See http://www.richelbilderbeek.nl/CppCompileErrorSwprintfHasNotBeenDeclared.htm

#undef __STRICT_ANSI__

#endif



//#include own header file as first substantive line of code, from:

// * John Lakos. Large-Scale C++ Software Design. 1996. ISBN: 0-201-63362-0. Section 3.2, page 110

#include "qtwidget.h"



#include <cassert>

#include <cmath>

#include <iostream>

#include <QGraphicsScene>

#include <QKeyEvent>

#include <QGraphicsSimpleTextItem>

#include "qtroundedrectitem.h"



QtWidget::QtWidget(QWidget *parent)

  : QGraphicsView(new QGraphicsScene,parent)

{

  const int n_items = 16;

  for (int i=0; i!=n_items; ++i)

  {

    const double angle = 2.0 * M_PI * (static_cast<double>(i) / static_cast<double>(n_items));

    {

      const double ray = 200.0;

      const double x =  std::sin(angle) * ray;

      const double y = -std::cos(angle) * ray;

      QtRoundedRectItem * const item = new QtRoundedRectItem;

      item->setPos(x,y);

      item->setRoundedRect(QRectF(-32.0,-32.0,64.0,64.0),16.0,16.0);

      scene()->addItem(item);

    }

    {

      const double ray = 120.0;

      const double x =  std::sin(angle) * ray;

      const double y = -std::cos(angle) * ray;

      QGraphicsRectItem * const item = new QGraphicsRectItem;

      item->setFlags(

          QGraphicsItem::ItemIsFocusable

        | QGraphicsItem::ItemIsMovable

        | QGraphicsItem::ItemIsSelectable);

      item->setPos(x,y);

      item->setRect(-16.0,-16.0,32.0,32.0);

      scene()->addItem(item);

    }

  }

}

crosscompiletowindows.sh


#!/bin/sh

#From http://richelbilderbeek.nl/CppQtCrosscompileToWindowsExample15.htm



echo "Cross compiling to Windows"



echo "1/2: Creating Windows makefile"

i686-pc-mingw32-qmake CppQtExample37.pro



echo "2/2: making makefile"



make



echo "Done"

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(C++) Qt example 37: rounded rectangle item