C++/Qt/QPixmap

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Create pixmal with QPixmap, save to png file

  
Foundations of Qt Development\Chapter07\paths\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * 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 APress 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, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QApplication>
#include <QPainter>
#include <QPainterPath>
#include <QPixmap>
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  
  QPixmap pixmap( 200, 200 );
  pixmap.fill( Qt::white );
    
  QPainterPath path;
  
  path.addEllipse( 80, 80, 80, 80 );
  
  path.moveTo( 120, 120 );
  path.lineTo( 120, 40 );
  path.arcTo( 40, 40, 160, 160, 90, 90 );
  path.lineTo( 120, 120 );
  
  QFont font = QApplication::font();
  font.setPixelSize( 40 );
  
  path.addText( 20, 180, font, "Path" );
  
  QPainter painter( &pixmap );
  painter.setRenderHint( QPainter::Antialiasing );
  
  painter.setPen( Qt::black );
  painter.setBrush( Qt::gray );
  
  painter.drawPath( path );
  
  pixmap.save( "path.png" );
  
  return 0;
}


Create screen shot

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef SCREENSHOT_H
#define SCREENSHOT_H
#include <QPixmap>
#include <QWidget>
QT_BEGIN_NAMESPACE
class QCheckBox;
class QGridLayout;
class QGroupBox;
class QHBoxLayout;
class QLabel;
class QPushButton;
class QSpinBox;
class QVBoxLayout;
QT_END_NAMESPACE

class Screenshot : public QWidget
{
    Q_OBJECT
public:
    Screenshot();
protected:
    void resizeEvent(QResizeEvent *event);
private slots:
    void newScreenshot();
    void saveScreenshot();
    void shootScreen();
    void updateCheckBox();
private:
    void createOptionsGroupBox();
    void createButtonsLayout();
    QPushButton *createButton(const QString &text, QWidget *receiver,
                              const char *member);
    void updateScreenshotLabel();
    QPixmap originalPixmap;
    QLabel *screenshotLabel;
    QGroupBox *optionsGroupBox;
    QSpinBox *delaySpinBox;
    QLabel *delaySpinBoxLabel;
    QCheckBox *hideThisWindowCheckBox;
    QPushButton *newScreenshotButton;
    QPushButton *saveScreenshotButton;
    QPushButton *quitScreenshotButton;
    QVBoxLayout *mainLayout;
    QGridLayout *optionsGroupBoxLayout;
    QHBoxLayout *buttonsLayout;
};

#endif



#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));
}



#include <QApplication>
#include "screenshot.h"
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Screenshot screenshot;
    screenshot.show();
    return app.exec();
}


Set mask for QPixmap

  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>
int main()
{
    int x, y;
    {
        QPixmap alpha("image-with-alpha.png");
        QPixmap alphacopy = alpha;
        alphacopy.setMask(alphacopy.mask());
    }

}