Revamp QtConcurrent examples to C++11

I updated signals and slots and for each loops to the new syntax and
replaced most free functions with std::function.

Task-number: QTBUG-60641
Change-Id: I7693f81f71c7f53fcbe83189a0de2fb76ddf99a8
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

1 files changed, 7 insertions, 5 deletions

diff --git a/examples/qtconcurrent/map/main.cpp b/examples/qtconcurrent/map/main.cpp
index d01b91fe55..8fc670b64b 100644
--- a/examples/qtconcurrent/map/main.cpp
+++ b/examples/qtconcurrent/map/main.cpp
@@ -55,11 +55,7 @@
 #include <QGuiApplication>
 #include <qtconcurrentmap.h>
 
-QImage scale(const QImage &image)
-{
-    qDebug() << "Scaling image in thread" << QThread::currentThread();
-    return image.scaled(QSize(100, 100), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
-}
+#include <functional>
 
 int main(int argc, char *argv[])
 {
@@ -72,6 +68,12 @@ int main(int argc, char *argv[])
     for (int i = 0; i < imageCount; ++i)
         images.append(QImage(1600, 1200, QImage::Format_ARGB32_Premultiplied));
 
+    std::function<QImage(const QImage&)> scale = [](const QImage &image) -> QImage
+    {
+        qDebug() << "Scaling image in thread" << QThread::currentThread();
+        return image.scaled(QSize(100, 100), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
+    };
+
     // Use QtConcurrentBlocking::mapped to apply the scale function to all the
     // images in the list.
     QList<QImage> thumbnails = QtConcurrent::blockingMapped(images, scale);