Qt 4.8: screenshot.cpp Example File (desktop/screenshot/screenshot.cpp)

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# screenshot.cpp Example File

desktop/screenshot/screenshot.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
     ** Contact: http://www.qt-project.org/legal
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** You may use this file under the terms of the BSD license as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
     **     of its contributors may be used to endorse or promote products derived
     **     from this software without specific prior written permission.
     **
     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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     ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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     ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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     ****************************************************************************/

     #include <QtGui>

     #include "screenshot.h"

     Screenshot::Screenshot()
     {
         screenshotLabel = new QLabel;
         screenshotLabel->setSizePolicy(QSizePolicy::Expanding,
                                        QSizePolicy::Expanding);
         screenshotLabel->setAlignment(Qt::AlignCenter);
         screenshotLabel->setMinimumSize(240, 160);

         createOptionsGroupBox();
         createButtonsLayout();

         mainLayout = new QVBoxLayout;
         mainLayout->addWidget(screenshotLabel);
         mainLayout->addWidget(optionsGroupBox);
         mainLayout->addLayout(buttonsLayout);
         setLayout(mainLayout);

         shootScreen();
         delaySpinBox->setValue(5);

         setWindowTitle(tr("Screenshot"));
         resize(300, 200);
     }

     void Screenshot::resizeEvent(QResizeEvent * /* event */)
     {
         QSize scaledSize = originalPixmap.size();
         scaledSize.scale(screenshotLabel->size(), Qt::KeepAspectRatio);
         if (!screenshotLabel->pixmap()
                 || scaledSize != screenshotLabel->pixmap()->size())
             updateScreenshotLabel();
     }

     void Screenshot::newScreenshot()
     {
         if (hideThisWindowCheckBox->isChecked())
             hide();
         newScreenshotButton->setDisabled(true);

         QTimer::singleShot(delaySpinBox->value() * 1000, this, SLOT(shootScreen()));
     }

     void Screenshot::saveScreenshot()
     {
         QString format = "png";
         QString initialPath = QDir::currentPath() + tr("/untitled.") + format;

         QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"),
                                    initialPath,
                                    tr("%1 Files (*.%2);;All Files (*)")
                                    .arg(format.toUpper())
                                    .arg(format));
         if (!fileName.isEmpty())
             originalPixmap.save(fileName, format.toAscii());
     }

     void Screenshot::shootScreen()
     {
         if (delaySpinBox->value() != 0)
             qApp->beep();
         originalPixmap = QPixmap(); // clear image for low memory situations
                                     // on embedded devices.
         originalPixmap = QPixmap::grabWindow(QApplication::desktop()->winId());
         updateScreenshotLabel();

         newScreenshotButton->setDisabled(false);
         if (hideThisWindowCheckBox->isChecked())
             show();
     }

     void Screenshot::updateCheckBox()
     {
         if (delaySpinBox->value() == 0) {
             hideThisWindowCheckBox->setDisabled(true);
             hideThisWindowCheckBox->setChecked(false);
         }
         else
             hideThisWindowCheckBox->setDisabled(false);
     }

     void Screenshot::createOptionsGroupBox()
     {
         optionsGroupBox = new QGroupBox(tr("Options"));

         delaySpinBox = new QSpinBox;
         delaySpinBox->setSuffix(tr(" s"));
         delaySpinBox->setMaximum(60);
         connect(delaySpinBox, SIGNAL(valueChanged(int)), this, SLOT(updateCheckBox()));

         delaySpinBoxLabel = new QLabel(tr("Screenshot Delay:"));

         hideThisWindowCheckBox = new QCheckBox(tr("Hide This Window"));

         optionsGroupBoxLayout = new QGridLayout;
         optionsGroupBoxLayout->addWidget(delaySpinBoxLabel, 0, 0);
         optionsGroupBoxLayout->addWidget(delaySpinBox, 0, 1);
         optionsGroupBoxLayout->addWidget(hideThisWindowCheckBox, 1, 0, 1, 2);
         optionsGroupBox->setLayout(optionsGroupBoxLayout);
     }

     void Screenshot::createButtonsLayout()
     {
         newScreenshotButton = createButton(tr("New Screenshot"),
                                            this, SLOT(newScreenshot()));

         saveScreenshotButton = createButton(tr("Save Screenshot"),
                                             this, SLOT(saveScreenshot()));

         quitScreenshotButton = createButton(tr("Quit"), this, SLOT(close()));

         buttonsLayout = new QHBoxLayout;
         buttonsLayout->addStretch();
         buttonsLayout->addWidget(newScreenshotButton);
         buttonsLayout->addWidget(saveScreenshotButton);
         buttonsLayout->addWidget(quitScreenshotButton);
     }

     QPushButton *Screenshot::createButton(const QString &text, QWidget *receiver,
                                           const char *member)
     {
         QPushButton *button = new QPushButton(text);
         button->connect(button, SIGNAL(clicked()), receiver, member);
         return button;
     }

     void Screenshot::updateScreenshotLabel()
     {
         screenshotLabel->setPixmap(originalPixmap.scaled(screenshotLabel->size(),
                                                          Qt::KeepAspectRatio,
                                                          Qt::SmoothTransformation));
     }