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/****************************************************************************
**
** Copyright (C) 2011 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.
**
** $QT_BEGIN_LICENSE:BSD$
** 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 Nokia Corporation 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,
** 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."
** $QT_END_LICENSE$
**
****************************************************************************/
//! [0]
U function(const T &t);
//! [0]
//! [1]
QImage scaled(const QImage &image)
{
return image.scaled(100, 100);
}
QList<QImage> images = ...;
QFuture<QImage> thumbnails = QtConcurrent::mapped(images, scaled);
//! [1]
//! [2]
U function(T &t);
//! [2]
//! [3]
void scale(QImage &image)
{
image = image.scaled(100, 100);
}
QList<QImage> images = ...;
QFuture<void> future = QtConcurrent::map(images, scale);
//! [3]
//! [4]
V function(T &result, const U &intermediate)
//! [4]
//! [5]
void addToCollage(QImage &collage, const QImage &thumbnail)
{
QPainter p(&collage);
static QPoint offset = QPoint(0, 0);
p.drawImage(offset, thumbnail);
offset += ...;
}
QList<QImage> images = ...;
QFuture<QImage> collage = QtConcurrent::mappedReduced(images, scaled, addToCollage);
//! [5]
//! [6]
QList<QImage> images = ...;
QFuture<QImage> thumbnails = QtConcurrent::mapped(images.constBegin(), images.constEnd(), scaled);
// map in-place only works on non-const iterators
QFuture<void> future = QtConcurrent::map(images.begin(), images.end(), scale);
QFuture<QImage> collage = QtConcurrent::mappedReduced(images.constBegin(), images.constEnd(), scaled, addToCollage);
//! [6]
//! [7]
QList<QImage> images = ...;
// each call blocks until the entire operation is finished
QList<QImage> future = QtConcurrent::blockingMapped(images, scaled);
QtConcurrent::blockingMap(images, scale);
QImage collage = QtConcurrent::blockingMappedReduced(images, scaled, addToCollage);
//! [7]
//! [8]
// squeeze all strings in a QStringList
QStringList strings = ...;
QFuture<void> squeezedStrings = QtConcurrent::map(strings, &QString::squeeze);
// swap the rgb values of all pixels on a list of images
QList<QImage> images = ...;
QFuture<QImage> bgrImages = QtConcurrent::mapped(images, &QImage::rgbSwapped);
// create a set of the lengths of all strings in a list
QStringList strings = ...;
QFuture<QSet<int> > wordLengths = QtConcurrent::mappedReduced(string, &QString::length, &QSet<int>::insert);
//! [8]
//! [9]
// can mix normal functions and member functions with QtConcurrent::mappedReduced()
// compute the average length of a list of strings
extern void computeAverage(int &average, int length);
QStringList strings = ...;
QFuture<int> averageWordLength = QtConcurrent::mappedReduced(strings, &QString::length, computeAverage);
// create a set of the color distribution of all images in a list
extern int colorDistribution(const QImage &string);
QList<QImage> images = ...;
QFuture<QSet<int> > totalColorDistribution = QtConcurrent::mappedReduced(images, colorDistribution, QSet<int>::insert);
//! [9]
//! [10]
QImage QImage::scaledToWidth(int width, Qt::TransformationMode) const;
//! [10]
//! [11]
boost::bind(&QImage::scaledToWidth, 100, Qt::SmoothTransformation)
//! [11]
//! [12]
QImage scaledToWith(const QImage &image)
//! [12]
//! [13]
QList<QImage> images = ...;
QFuture<QImage> thumbnails = QtConcurrent::mapped(images, boost::bind(&QImage::scaledToWidth, 100 Qt::SmoothTransformation));
//! [13]
//! [14]
struct Scaled
{
Scaled(int size)
: m_size(size) { }
typedef QImage result_type;
QImage operator()(const QImage &image)
{
return image.scaled(m_size, m_size);
}
int m_size;
};
QList<QImage> images = ...;
QFuture<QImage> thumbnails = QtConcurrent::mapped(images, Scaled(100));
//! [14]
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