CG2_Tasks/imageviewer-qt4.cpp

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 #include "imageviewer-qt4.h"

 ImageViewer::ImageViewer()
 {
 	image=NULL;	
	
	startLogging();

	generateMainGui();
	renewLogging();

	generateControlPanels();
    	createActions();
    	createMenus();

     resize(1600, 600);
 }

void ImageViewer::drawBlackLine()
{
  if(image!=NULL) {
    for(int i=0;i<std::min(image->width(),image->height());i++) {
      image->setPixel(i,i,0);
    }
    updateImageDisplay();
    logFile << "Black line drawn." << std::endl;
    renewLogging();
  }
}

void ImageViewer::drawDiagonalCross() {
  if(image!=NULL) {
    int color = QColor::fromHsl(120,255,125).rgba();
    int width = image->width();
    int height = image->height();
    for(int y=0; y<image->height(); y++) {
      image->setPixel((1.0*y/height)*width,y,color); //holy shit, ez gg!
    }
  }
  updateImageDisplay();
  logFile << "Let's try a diagonal cross now." << std::endl;
  renewLogging();
}


//Proxy-Method to actual algorithm
void ImageViewer::drawRainbowCross() {
  drawRainbowCross(0);
}

void ImageViewer::drawRainbowCross(int initialHue=0) {
  if(image!=NULL) {
    int h = initialHue;
    QColor myColor = QColor::fromHsl(h, 255, 125);
    int image_width = image->width()-1;
    int range = lineSlider->value();
    if(range > image->width()-2) range = image->width()-2;
    for(int i=0;i<std::min(image->width(),image->height());i++) {
      int color = myColor.rgba();
      for(int r=0; r<range; r++) {
	image->setPixel(i+r,i,color);
	image->setPixel((image_width-i)-r,i,color);
      }
      h++;
      if(h > 359) h = 0;
      myColor.setHsl(h, 255, 125);
    }
    updateImageDisplay();
  }
}

void ImageViewer::acidTrippin() {
  logFile << "There is no stop button yet. Kill the process or keep it." << std::endl;
  renewLogging();
  int h = 0;
  while(true) {
    drawRainbowCross(h);
    h += 20;
    if(h > 359) h = 0;
    qApp->processEvents();
  }
}

/**************************************************************************************** 
*   
*  mit dieser Methode können sie sich pro Aufgabe ein  Tab anlegen, in der die Ein-
*  stellungen per Slider, Button, Checkbox etc. gemacht werden und die zu implemen-
*  tierenden Algorithmen gestatet werden.
*
*****************************************************************************************/

void ImageViewer::generateControlPanels()
{
	// first tab

    	m_option_panel1 = new QWidget();
	m_option_layout1 = new QVBoxLayout();
	m_option_panel1->setLayout(m_option_layout1);      

	button1 = new QPushButton();
	button1->setText("Draw a black line");

	button2 = new QPushButton();
	button2->setText("Draw a rainbow cross");

	button3 = new QPushButton();
	button3->setText("Start the neverending acid trip!");
	
	button4 = new QPushButton();
	button4->setText("Draw a diagonal cross");
	
	lineSlider = new QSlider(Qt::Horizontal);
	lineSlider->setMinimum(1);
	lineSlider->setMaximum(150);
	lineSlider->setValue(3);

	QObject::connect(button1, SIGNAL (clicked()), this, SLOT (drawBlackLine()));
	QObject::connect(button2, SIGNAL (clicked()), this, SLOT (drawRainbowCross()));
	QObject::connect(button3, SIGNAL (clicked()), this, SLOT (acidTrippin()));
	QObject::connect(button4, SIGNAL (clicked()), this, SLOT (drawDiagonalCross()));
	//QObject::connect(lineSlider, SIGNAL (valueChanged(int)), this, SLOT (drawRainbowCross()));
 
	m_option_layout1->addWidget(new QLabel("Let's draw something!"));
	m_option_layout1->addWidget(button1);
	m_option_layout1->addWidget(button2);
	m_option_layout1->addWidget(button3);
	m_option_layout1->addWidget(button4);
	m_option_layout1->addWidget(new QLabel("This will not stop unless process is killed."));
	m_option_layout1->addWidget(lineSlider);
	m_option_layout1->addWidget(new QLabel("Sets the width of the cross."));

	tabWidget->addTab(m_option_panel1,"Task #1");   

	// another tab 
        m_option_panel2 = new QWidget();
	m_option_layout2 = new QVBoxLayout();
	m_option_panel2->setLayout(m_option_layout2);      

	spinbox1 = new QSpinBox(tabWidget);

	m_option_layout2->addWidget(new QLabel("Here we put some more controls later."));
	m_option_layout2->addWidget(spinbox1);

	tabWidget->addTab(m_option_panel2,"Task #2");
	tabWidget->show();

	// Hinweis: Es bietet sich an pro Aufgabe jeweils einen solchen Tab zu erstellen
}

/**************************************************************************************** 
*
*   ab hier kommen technische Details, die nicht notwenig für das Verständnis und die 
*   Bearbeitung sind.
*
*
*****************************************************************************************/

void ImageViewer::startLogging()
{
	//LogFile
	logFile.open("log.txt", std::ios::out);
	logFile << "Logging: \n" << std::endl;
}

void ImageViewer::renewLogging()
{
	QFile file("log.txt"); // Create a file handle for the file named
	QString line;
	file.open(QIODevice::ReadOnly); // Open the file

	QTextStream stream( &file ); // Set the stream to read from myFile
	logBrowser->clear();
	while(!stream.atEnd()){

		line = stream.readLine(); // this reads a line (QString) from the file
		logBrowser->append(line);
	}
}

void ImageViewer::updateImageDisplay()
{
	imageLabel->setPixmap(QPixmap::fromImage(*image));
}


void ImageViewer::generateMainGui()
{
	/* Tab widget */
        tabWidget = new QTabWidget(this);
	tabWidget->setObjectName("tabWidget");
	


	/* Center widget */
	centralwidget = new QWidget(this);
	centralwidget->setObjectName("centralwidget");
	//centralwidget->setFixedSize(200,200);
	//setCentralWidget(centralwidget);

    	imageLabel = new QLabel;
 	imageLabel->setBackgroundRole(QPalette::Base);
    	imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
    	imageLabel->setScaledContents(true);
	

	/* Center widget */
	scrollArea = new QScrollArea;
   	scrollArea->setBackgroundRole(QPalette::Dark);
    	scrollArea->setWidget(imageLabel);
	
	
    	setCentralWidget(scrollArea);

	/* HBox layout */
	QGridLayout* gLayout = new QGridLayout(centralwidget);
	gLayout->setObjectName("hboxLayout");
	gLayout->addWidget(new QLabel(),1,1);
	gLayout->setVerticalSpacing(50);
	gLayout->addWidget(tabWidget,2,1);
	gLayout->addWidget(scrollArea,2,2);
	
	logBrowser= new QTextEdit(this);
	logBrowser->setMinimumHeight(100);
	logBrowser->setMaximumHeight(200);
	logBrowser->setMinimumWidth(width());
	logBrowser->setMaximumWidth(width());
	gLayout->addWidget(logBrowser,3,1,1,2);
	gLayout->setVerticalSpacing(50);
}

void ImageViewer::print()
{
    Q_ASSERT(imageLabel->pixmap());
#if !defined(QT_NO_PRINTER) && !defined(QT_NO_PRINTDIALOG)
    QPrintDialog dialog(&printer, this);
    if (dialog.exec()) {
        QPainter painter(&printer);
        QRect rect = painter.viewport();
        QSize size = imageLabel->pixmap()->size();
        size.scale(rect.size(), Qt::KeepAspectRatio);
        painter.setViewport(rect.x(), rect.y(), size.width(), size.height());
        painter.setWindow(imageLabel->pixmap()->rect());
        painter.drawPixmap(0, 0, *imageLabel->pixmap());
    }
#endif
}

void ImageViewer::open()
{
    if(image!=NULL)
    {
	delete image;
	image=NULL;
    }

      QString fileName = QFileDialog::getOpenFileName(this,
                                     tr("Open File"), QDir::currentPath());
     if (!fileName.isEmpty()) {
         image = new QImage(fileName);
         if (image->isNull()) {
             QMessageBox::information(this, tr("Image Viewer"),
                                      tr("Cannot load %1.").arg(fileName));
             return;
         }
    	
    
    scaleFactor = 1.0;

    
    updateImageDisplay();

    printAct->setEnabled(true);
    fitToWindowAct->setEnabled(true);
    updateActions();

    if (!fitToWindowAct->isChecked())
        imageLabel->adjustSize();

    setWindowFilePath(fileName);
    logFile << "geladen: " << fileName.toStdString().c_str()  << std::endl;
    renewLogging();
    }
}


void ImageViewer::resizeEvent(QResizeEvent * event)
{
	QMainWindow::resizeEvent(event);
	centralwidget->setMinimumWidth(width());	
    	centralwidget->setMinimumHeight(height());
	centralwidget->setMaximumWidth(width());	
    	centralwidget->setMaximumHeight(height());
 	logBrowser->setMinimumWidth(width()-40);
    	logBrowser->setMaximumWidth(width()-40);
}

 void ImageViewer::zoomIn()
 {
     scaleImage(1.25);
 }

 void ImageViewer::zoomOut()
 {
     scaleImage(0.8);
 }

 void ImageViewer::normalSize()
 {
     imageLabel->adjustSize();
     scaleFactor = 1.0;
 }

 void ImageViewer::fitToWindow()
 {
     bool fitToWindow = fitToWindowAct->isChecked();
     scrollArea->setWidgetResizable(fitToWindow);
     if (!fitToWindow) {
         normalSize();
     }
     updateActions();
 }

 void ImageViewer::about()
 {
     QMessageBox::about(this, tr("About Image Viewer"),
             tr("<p>The <b>Image Viewer</b> example shows how to combine QLabel "
                "and QScrollArea to display an image. QLabel is typically used "
                "for displaying a text, but it can also display an image. "
                "QScrollArea provides a scrolling view around another widget. "
                "If the child widget exceeds the size of the frame, QScrollArea "
                "automatically provides scroll bars. </p><p>The example "
                "demonstrates how QLabel's ability to scale its contents "
                "(QLabel::scaledContents), and QScrollArea's ability to "
                "automatically resize its contents "
                "(QScrollArea::widgetResizable), can be used to implement "
                "zooming and scaling features. </p><p>In addition the example "
                "shows how to use QPainter to print an image.</p>"));
 }

 void ImageViewer::createActions()
 {
     openAct = new QAction(tr("&Open..."), this);
     openAct->setShortcut(tr("Ctrl+O"));
     connect(openAct, SIGNAL(triggered()), this, SLOT(open()));

     printAct = new QAction(tr("&Print..."), this);
     printAct->setShortcut(tr("Ctrl+P"));
     printAct->setEnabled(false);
     connect(printAct, SIGNAL(triggered()), this, SLOT(print()));

     exitAct = new QAction(tr("E&xit"), this);
     exitAct->setShortcut(tr("Ctrl+Q"));
     connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));

     zoomInAct = new QAction(tr("Zoom &In (25%)"), this);
     zoomInAct->setShortcut(tr("Ctrl++"));
     zoomInAct->setEnabled(false);
     connect(zoomInAct, SIGNAL(triggered()), this, SLOT(zoomIn()));

     zoomOutAct = new QAction(tr("Zoom &Out (25%)"), this);
     zoomOutAct->setShortcut(tr("Ctrl+-"));
     zoomOutAct->setEnabled(false);
     connect(zoomOutAct, SIGNAL(triggered()), this, SLOT(zoomOut()));

     normalSizeAct = new QAction(tr("&Normal Size"), this);
     normalSizeAct->setShortcut(tr("Ctrl+S"));
     normalSizeAct->setEnabled(false);
     connect(normalSizeAct, SIGNAL(triggered()), this, SLOT(normalSize()));

     fitToWindowAct = new QAction(tr("&Fit to Window"), this);
     fitToWindowAct->setEnabled(false);
     fitToWindowAct->setCheckable(true);
     fitToWindowAct->setShortcut(tr("Ctrl+F"));
     connect(fitToWindowAct, SIGNAL(triggered()), this, SLOT(fitToWindow()));

     aboutAct = new QAction(tr("&About"), this);
     connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));

     aboutQtAct = new QAction(tr("About &Qt"), this);
     connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
 }

 void ImageViewer::createMenus()
 {
     fileMenu = new QMenu(tr("&File"), this);
     fileMenu->addAction(openAct);
     fileMenu->addAction(printAct);
     fileMenu->addSeparator();
     fileMenu->addAction(exitAct);

     viewMenu = new QMenu(tr("&View"), this);
     viewMenu->addAction(zoomInAct);
     viewMenu->addAction(zoomOutAct);
     viewMenu->addAction(normalSizeAct);
     viewMenu->addSeparator();
     viewMenu->addAction(fitToWindowAct);

     helpMenu = new QMenu(tr("&Help"), this);
     helpMenu->addAction(aboutAct);
     helpMenu->addAction(aboutQtAct);

     menuBar()->addMenu(fileMenu);
     menuBar()->addMenu(viewMenu);
     menuBar()->addMenu(helpMenu);
 }

 void ImageViewer::updateActions()
 {
     zoomInAct->setEnabled(!fitToWindowAct->isChecked());
     zoomOutAct->setEnabled(!fitToWindowAct->isChecked());
     normalSizeAct->setEnabled(!fitToWindowAct->isChecked());
 }

 void ImageViewer::scaleImage(double factor)
 {
     Q_ASSERT(imageLabel->pixmap());
     scaleFactor *= factor;
     imageLabel->resize(scaleFactor * imageLabel->pixmap()->size());

     adjustScrollBar(scrollArea->horizontalScrollBar(), factor);
     adjustScrollBar(scrollArea->verticalScrollBar(), factor);

     zoomInAct->setEnabled(scaleFactor < 3.0);
     zoomOutAct->setEnabled(scaleFactor > 0.333);
 }

 void ImageViewer::adjustScrollBar(QScrollBar *scrollBar, double factor)
 {
     scrollBar->setValue(int(factor * scrollBar->value()
                             + ((factor - 1) * scrollBar->pageStep()/2)));
 }