Screenshot Example

#ifndef SCREENSHOT_H
#define SCREENSHOT_H
#include <QPixmap>
#include <QWidget>

class QCheckBox;
class QGridLayout;
class QGroupBox;
class QHBoxLayout;
class QLabel;
class QPushButton;
class QSpinBox;
class QVBoxLayout;

class Screenshot:public QWidget
{
 Q_OBJECT
public:
 Screenshot();
protected:
 void resizeEvent(QResizeEvent* event);
private slots:
 void new_screenshot();
 void save_screenshot();
 void shoot_screenshot();
 void update_checkbox();
private:
 void create_options_groupbox();
 void create_buttons_layout();
 QPushButton* create_button(const QString &text,QWidget* receiver, const char* members);
 void update_screenshot_label();

 QPixmap original_pixmap_;
 QLabel* screenshot_label_;
 QGroupBox* options_groupbox_;
 QSpinBox* delay_spinbox_;
 QLabel* delay_spinbox_label_;
 QCheckBox* hide_this_window_checkbox_;
 QPushButton* new_screenshot_button_;
 QPushButton* save_screenshot_button_;
 QPushButton* quit_screenshot_button_;
 QVBoxLayout* main_layout_;
 QGridLayout* options_groupbox_layout_;
 QHBoxLayout* butttons_layout_;
};

#endif

#include "screenshot.h"

#include <QtGui>

Screenshot::Screenshot()
{
 screenshot_label_ = new QLabel;
 screenshot_label_->setSizePolicy(QSizePolicy::Expanding,
  QSizePolicy::Expanding);
 screenshot_label_->setAlignment(Qt::AlignCenter);
 screenshot_label_->setMinimumSize(240, 160);
 create_options_groupbox();
 create_buttons_layout();
 main_layout_ = new QVBoxLayout;
 main_layout_->addWidget(screenshot_label_);
 main_layout_->addWidget(options_groupbox_);
 main_layout_->addLayout(butttons_layout_);
 setLayout(main_layout_);
 shoot_screenshot();
 delay_spinbox_->setValue(5);
 setWindowTitle(tr("Screenshot"));
 resize(300, 200);
}

void Screenshot::resizeEvent(QResizeEvent* event)
{
 QSize scaled_size = original_pixmap_.size();
 scaled_size.scale(screenshot_label_->size(), Qt::KeepAspectRatio);
 if (!screenshot_label_->pixmap() || scaled_size != screenshot_label_->pixmap()->size())
 {
  update_screenshot_label();
 }
}

void Screenshot::new_screenshot()
{
 if (hide_this_window_checkbox_->isChecked())
 {
  hide();
 }
 new_screenshot_button_->setDisabled(true);
 QTimer::singleShot(delay_spinbox_->value() * 1000, this, SLOT(shoot_screenshot()));
}

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

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

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

 new_screenshot_button_->setDisabled(false);
 if (hide_this_window_checkbox_->isChecked())
  show();
}

void Screenshot::update_checkbox()
{
 if (delay_spinbox_->value() == 0) {
  hide_this_window_checkbox_->setDisabled(true);
  hide_this_window_checkbox_->setChecked(false);
 }
 else
  hide_this_window_checkbox_->setDisabled(false);
}

void Screenshot::create_options_groupbox()
{
 options_groupbox_ = new QGroupBox(tr("Options"));

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

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

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

 options_groupbox_layout_ = new QGridLayout;
 options_groupbox_layout_->addWidget(delay_spinbox_label_, 0, 0);
 options_groupbox_layout_->addWidget(delay_spinbox_, 0, 1);
 options_groupbox_layout_->addWidget(hide_this_window_checkbox_, 1, 0, 1, 2);
 options_groupbox_->setLayout(options_groupbox_layout_);
}

void Screenshot::create_buttons_layout()
{
 new_screenshot_button_ = create_button(tr("New Screenshot"),
  this, SLOT(new_screenshot()));

 save_screenshot_button_ = create_button(tr("Save Screenshot"),
  this, SLOT(save_screenshot()));

 quit_screenshot_button_ = create_button(tr("Quit"), this, SLOT(close()));

 butttons_layout_ = new QHBoxLayout;
 butttons_layout_->addStretch();
 butttons_layout_->addWidget(new_screenshot_button_);
 butttons_layout_->addWidget(save_screenshot_button_);
 butttons_layout_->addWidget(quit_screenshot_button_);
}

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

void Screenshot::update_screenshot_label()
{
 screenshot_label_->setPixmap(original_pixmap_.scaled(screenshot_label_->size(),
  Qt::KeepAspectRatio,
  Qt::SmoothTransformation));
}


 

#include "screenshot.h"
#include <QtGui/QApplication>

int main(int argc, char *argv[])
{
 QApplication a(argc, argv);
 Screenshot w;
 w.show();
 return a.exec();
}