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Diffstat (limited to 'doc/codesnippets/doc/src/snippets/code/src_corelib_concurrent_qtconcurrentmap.cpp')
-rw-r--r-- | doc/codesnippets/doc/src/snippets/code/src_corelib_concurrent_qtconcurrentmap.cpp | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/doc/codesnippets/doc/src/snippets/code/src_corelib_concurrent_qtconcurrentmap.cpp b/doc/codesnippets/doc/src/snippets/code/src_corelib_concurrent_qtconcurrentmap.cpp new file mode 100644 index 000000000..cbff31892 --- /dev/null +++ b/doc/codesnippets/doc/src/snippets/code/src_corelib_concurrent_qtconcurrentmap.cpp @@ -0,0 +1,144 @@ +//! [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] |