123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206 | // Copyright (C) 2016 The Qt Company Ltd.// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause//! [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]voidscale(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]voidaddToCollage(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,static_cast<QImage(QImage::*)()const&>(&QImage::rgbSwapped));// Create a set of the lengths of all strings in a list. QStringList strings = ...; QFuture<QSet<int>> wordLengths =QtConcurrent::mappedReduced(strings, &QString::length, qOverload<const int&>(&QSet<int>::insert));//! [8]//! [9]// Can mix normal functions and member functions with QtConcurrent::mappedReduced().// Compute the average length of a list of strings.externvoidcomputeAverage(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.externintcolorDistribution(const QImage &string); QList<QImage> images = ...; QFuture<QSet<int>> totalColorDistribution =QtConcurrent::mappedReduced(images, colorDistribution, qOverload<const int&>(&QSet<int>::insert));//! [9]//! [10] QImage QImage::scaledToWidth(int width,Qt::TransformationMode)const;//! [10]//! [11]struct ImageTransform {voidoperator()(QImage &result,const QImage &value);}; QFuture<QImage> thumbNails =QtConcurrent::mappedReduced(images,Scaled(100),ImageTransform(),QtConcurrent::SequentialReduce);//! [11]//! [13] QList<QImage> images = ...;std::function<QImage(const QImage &)> scale = [](const QImage &img) {return img.scaledToWidth(100,Qt::SmoothTransformation);}; QFuture<QImage> thumbnails =QtConcurrent::mapped(images, scale);//! [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]//! [15] QList<int> vector {1,2,3,4};QtConcurrent::blockingMap(vector, [](int&x) { x *=2; });int size =100; QList<QImage> images = ...; QList<QImage> thumbnails =QtConcurrent::mapped(images,[&size](const QImage &image) {return image.scaled(size, size);}).results();//! [15]//! [16] QList<QImage> collage =QtConcurrent::mappedReduced(images,[&size](const QImage &image) {return image.scaled(size, size);}, addToCollage ).results();//! [16]//! [17] QList<QImage> collage =QtConcurrent::mappedReduced(images,[&size](const QImage &image) {return image.scaled(size, size);},[](QImage &result,const QImage &value) {// do some transformation}).results();//! [17]//! [18]auto process = [](int val) {return val *2;}; QList<int> inputs {1,2,3};auto badFuture =QtConcurrent::mapped(inputs, process).then([](int val) {qDebug() << val;});auto goodFuture =QtConcurrent::mapped(inputs, process).then([](QFuture<int> f) {for(auto r : f.results()) {qDebug() << r;}});//! [18]
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