(C++) QtExample19

 

 

This Qt example shows how to create a GUI around a program that displays a rotating image, like this screenshot (png).

 

• Download the Qt Project of 'QtExample19' (zip)

Technical facts

 

Application type(s)

• Desktop application

Operating system(s) or programming environment(s)

• Lubuntu 15.04 (vivid)

IDE(s):

• Qt Creator 3.1.1

Project type:

• GUI application

C++ standard:

• C++11

Compiler(s):

• G++ 4.9.2

Libraries used:

• Qt: version 5.4.1 (32 bit)
• STL: GNU ISO C++ Library, version 4.9.2

 

 

 

 

 

Qt project file: ./CppQtExample19/CppQtExample19.pro

 

---

exists(../../DesktopApplication.pri) {   include(../../DesktopApplication.pri) } !exists(../../DesktopApplication.pri) {   QT += core gui   greaterThan(QT_MAJOR_VERSION, 4): QT += widgets   TEMPLATE = app   CONFIG(debug, debug|release) {     message(Debug mode)   }   CONFIG(release, debug|release) {     message(Release mode)     DEFINES += NDEBUG NTRACE_BILDERBIKKEL   }   QMAKE_CXXFLAGS += -std=c++11 -Wall -Wextra   unix {     QMAKE_CXXFLAGS += -Werror   } } exists(../../Libraries/Boost.pri) {   include(../../Libraries/Boost.pri) } !exists(../../Libraries/Boost.pri) {   win32 {     INCLUDEPATH += \       ../../../Projects/Libraries/boost_1_55_0   } } SOURCES += main.cpp SOURCES += dialogmain.cpp HEADERS += dialogmain.h FORMS   += dialogmain.ui RESOURCES += resources.qrc

 

 

 

 

 

./CppQtExample19/dialogmain.h

 

---

#ifndef DIALOGMAIN_H #define DIALOGMAIN_H #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #include <QDialog> #pragma GCC diagnostic pop struct QGraphicsScene; struct QGraphicsPixmapItem; namespace Ui {   class DialogMain; } class DialogMain : public QDialog {   Q_OBJECT public:   explicit DialogMain(QWidget *parent = 0);   DialogMain(const DialogMain&) = delete;   DialogMain& operator=(const DialogMain&) = delete;   ~DialogMain(); private:   Ui::DialogMain *ui;   QTimer * const m_timer;   QGraphicsScene * const m_scene;   QGraphicsPixmapItem * const m_sprite;   double m_angle;   void resizeEvent(QResizeEvent*);   void keyPressEvent(QKeyEvent* e); private slots:   void onTick();   void onCheck();   void onButtonLeft();   void onButtonRight(); }; #endif // DIALOGMAIN_H

 

 

 

 

 

./CppQtExample19/dialogmain.cpp

 

---

#include "dialogmain.h" #include <cassert> #include <cmath> #include <iostream> #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #include <QDesktopWidget> #include <QGraphicsPixmapItem> #include <QGraphicsScene> #include <QKeyEvent> #include <QTimer> #include "ui_dialogmain.h" #pragma GCC diagnostic pop DialogMain::DialogMain(QWidget *parent) :   QDialog(parent),   ui(new Ui::DialogMain),   m_timer(new QTimer(this)),   m_scene(new QGraphicsScene(this)),   m_sprite(new QGraphicsPixmapItem),   m_angle(0.0) {   ui->setupUi(this);   //Load the sprite   m_sprite->setPixmap(QPixmap(":/images/R.png"));   assert(!m_sprite->pixmap().isNull());   //Set the center of the sprite for rotation   m_sprite->setTransformOriginPoint(     static_cast<double>(m_sprite->pixmap().width()) / 2.0,     static_cast<double>(m_sprite->pixmap().height()) / 2.0);   //Add the sprite to the scene   m_scene->addItem(m_sprite);   //Add the scene to the view   ui->graphicsView->setScene(m_scene);   //Connect and start a timer   QObject::connect(m_timer,SIGNAL(timeout()),this,SLOT(onTick()));   QObject::connect(ui->check_auto_rotate,SIGNAL(clicked()),this,SLOT(onCheck()));   QObject::connect(ui->button_left,SIGNAL(clicked()),this,SLOT(onButtonLeft()));   QObject::connect(ui->button_right,SIGNAL(clicked()),this,SLOT(onButtonRight()));   //Start the timer   m_timer->start(100);   this->setGeometry(0,0,     static_cast<int>(640),     static_cast<int>(640));   const QRect screen = QApplication::desktop()->screenGeometry();   this->move( screen.center() - this->rect().center() ); } DialogMain::~DialogMain() {   delete ui;   delete m_sprite; } //Sets the scale of the maze void DialogMain::resizeEvent(QResizeEvent*) {   const int size = std::max(     m_sprite->pixmap().width(),     m_sprite->pixmap().height());   const double scale = 0.9     * std::min(ui->graphicsView->width(),         ui->graphicsView->height())     / (static_cast<double>(size) * std::sqrt(2.0));   m_sprite->setScale(scale); } void DialogMain::keyPressEvent(QKeyEvent* e) {   switch (e->key())   {     case Qt::Key_Left: case Qt::Key_Minus: case Qt::Key_A:       m_angle-=1.0;       m_sprite->setRotation(m_angle);       break;     case Qt::Key_Right: case Qt::Key_Plus: case Qt::Key_D:       m_angle+=1.0;       m_sprite->setRotation(m_angle);       break;   } } void DialogMain::onTick() {   m_angle+=1.0;   m_sprite->setRotation(m_angle); } void DialogMain::onCheck() {   if (ui->check_auto_rotate->isChecked())   {     m_timer->start();   }   else   {     m_timer->stop();   } } void DialogMain::onButtonLeft() {   m_angle-=1.0;   m_sprite->setRotation(m_angle); } void DialogMain::onButtonRight() {   m_angle+=1.0;   m_sprite->setRotation(m_angle); }

 

 

 

 

 

./CppQtExample19/main.cpp

 

---

#pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #include <QApplication> #include "dialogmain.h" #pragma GCC diagnostic pop int main(int argc, char *argv[]) {   QApplication a(argc, argv);   DialogMain w;   w.show();   return a.exec(); }