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50
51#include <QImage>
52#include <QList>
53#include <QThread>
54#include <QDebug>
55#include <QGuiApplication>
56#include <qtconcurrentmap.h>
57
58#include <functional>
59
60int main(int argc, char *argv[])
61{
62 QGuiApplication app(argc, argv);
63
64 const int imageCount = 20;
65
66 // Create a list containing imageCount images.
67 QList<QImage> images;
68 for (int i = 0; i < imageCount; ++i)
69 images.append(t: QImage(1600, 1200, QImage::Format_ARGB32_Premultiplied));
70
71 std::function<QImage(const QImage&)> scale = [](const QImage &image) -> QImage
72 {
73 qDebug() << "Scaling image in thread" << QThread::currentThread();
74 return image.scaled(s: QSize(100, 100), aspectMode: Qt::IgnoreAspectRatio, mode: Qt::SmoothTransformation);
75 };
76
77 // Use QtConcurrentBlocking::mapped to apply the scale function to all the
78 // images in the list.
79 QList<QImage> thumbnails = QtConcurrent::blockingMapped(sequence: images, map: scale);
80
81 return 0;
82}
83

source code of qtbase/examples/qtconcurrent/map/main.cpp