Examples: Cleanup and modernize Plug&Paint

* Use C++11 member init
* Use auto where appropriate
* Replace foreach with range-for
* Replace last Qt4-style connects
* Sort includes to common style
* Fix some Clang warnings

Task-number: QTBUG-60635
Change-Id: I61c98b34b954e416dd175b56ca589125217083de
Reviewed-by: Venugopal Shivashankar <Venugopal.Shivashankar@qt.io>
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

9 files changed, 91 insertions, 99 deletions

diff --git a/examples/widgets/tools/plugandpaint/app/main.cpp b/examples/widgets/tools/plugandpaint/app/main.cpp
index f157957da5..f50fd86b97 100644
--- a/examples/widgets/tools/plugandpaint/app/main.cpp
+++ b/examples/widgets/tools/plugandpaint/app/main.cpp
@@ -50,8 +50,9 @@
 
 //! [0]
 #include "mainwindow.h"
-#include <QtPlugin>
+
 #include <QApplication>
+#include <QtPlugin>
 
 Q_IMPORT_PLUGIN(BasicToolsPlugin)
 
diff --git a/examples/widgets/tools/plugandpaint/app/mainwindow.cpp b/examples/widgets/tools/plugandpaint/app/mainwindow.cpp
index b2287ee072..ebe1150eea 100644
--- a/examples/widgets/tools/plugandpaint/app/mainwindow.cpp
+++ b/examples/widgets/tools/plugandpaint/app/mainwindow.cpp
@@ -54,19 +54,18 @@
 #include "paintarea.h"
 #include "plugindialog.h"
 
-#include <QPluginLoader>
-#include <QTimer>
-
-#include <QScrollArea>
-#include <QMessageBox>
-#include <QActionGroup>
 #include <QAction>
-#include <QMenu>
-#include <QMenuBar>
-#include <QFileDialog>
+#include <QActionGroup>
+#include <QApplication>
 #include <QColorDialog>
+#include <QFileDialog>
 #include <QInputDialog>
-#include <QApplication>
+#include <QMenu>
+#include <QMenuBar>
+#include <QMessageBox>
+#include <QPluginLoader>
+#include <QScrollArea>
+#include <QTimer>
 
 MainWindow::MainWindow() :
     paintArea(new PaintArea),
@@ -109,11 +108,10 @@ bool MainWindow::saveAs()
 
     const QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"),
                                                           initialPath);
-    if (fileName.isEmpty()) {
+    if (fileName.isEmpty())
         return false;
-    } else {
-        return paintArea->saveImage(fileName, "png");
-    }
+
+    return paintArea->saveImage(fileName, "png");
 }
 
 void MainWindow::brushColor()
@@ -137,8 +135,8 @@ void MainWindow::brushWidth()
 //! [0]
 void MainWindow::changeBrush()
 {
-    QAction *action = qobject_cast<QAction *>(sender());
-    BrushInterface *iBrush = qobject_cast<BrushInterface *>(action->parent());
+    auto action = qobject_cast<QAction *>(sender());
+    auto iBrush = qobject_cast<BrushInterface *>(action->parent());
     const QString brush = action->text();
 
     paintArea->setBrush(iBrush, brush);
@@ -148,8 +146,8 @@ void MainWindow::changeBrush()
 //! [1]
 void MainWindow::insertShape()
 {
-    QAction *action = qobject_cast<QAction *>(sender());
-    ShapeInterface *iShape = qobject_cast<ShapeInterface *>(action->parent());
+    auto action = qobject_cast<QAction *>(sender());
+    auto iShape = qobject_cast<ShapeInterface *>(action->parent());
 
     const QPainterPath path = iShape->generateShape(action->text(), this);
     if (!path.isEmpty())
@@ -160,9 +158,8 @@ void MainWindow::insertShape()
 //! [2]
 void MainWindow::applyFilter()
 {
-    QAction *action = qobject_cast<QAction *>(sender());
-    FilterInterface *iFilter =
-            qobject_cast<FilterInterface *>(action->parent());
+    auto action = qobject_cast<QAction *>(sender());
+    auto iFilter = qobject_cast<FilterInterface *>(action->parent());
 
     const QImage image = iFilter->filterImage(action->text(), paintArea->image(),
                                               this);
@@ -245,7 +242,8 @@ void MainWindow::createMenus()
 //! [4]
 void MainWindow::loadPlugins()
 {
-    foreach (QObject *plugin, QPluginLoader::staticInstances())
+    const auto staticInstances = QPluginLoader::staticInstances();
+    for (QObject *plugin : staticInstances)
         populateMenus(plugin);
 //! [4] //! [5]
 
@@ -265,7 +263,8 @@ void MainWindow::loadPlugins()
 //! [5]
 
 //! [6]
-    foreach (QString fileName, pluginsDir.entryList(QDir::Files)) {
+    const auto entryList = pluginsDir.entryList(QDir::Files);
+    for (const QString &fileName : entryList) {
         QPluginLoader loader(pluginsDir.absoluteFilePath(fileName));
         QObject *plugin = loader.instance();
         if (plugin) {
@@ -287,16 +286,16 @@ void MainWindow::loadPlugins()
 //! [10]
 void MainWindow::populateMenus(QObject *plugin)
 {
-    BrushInterface *iBrush = qobject_cast<BrushInterface *>(plugin);
+    auto iBrush = qobject_cast<BrushInterface *>(plugin);
     if (iBrush)
         addToMenu(plugin, iBrush->brushes(), brushMenu, &MainWindow::changeBrush,
                   brushActionGroup);
 
-    ShapeInterface *iShape = qobject_cast<ShapeInterface *>(plugin);
+    auto iShape = qobject_cast<ShapeInterface *>(plugin);
     if (iShape)
         addToMenu(plugin, iShape->shapes(), shapesMenu, &MainWindow::insertShape);
 
-    FilterInterface *iFilter = qobject_cast<FilterInterface *>(plugin);
+    auto iFilter = qobject_cast<FilterInterface *>(plugin);
     if (iFilter)
         addToMenu(plugin, iFilter->filters(), filterMenu, &MainWindow::applyFilter);
 }
@@ -306,8 +305,8 @@ void MainWindow::addToMenu(QObject *plugin, const QStringList &texts,
                            QMenu *menu, Member member,
                            QActionGroup *actionGroup)
 {
-    foreach (QString text, texts) {
-        QAction *action = new QAction(text, plugin);
+    for (const QString &text : texts) {
+        auto action = new QAction(text, plugin);
         connect(action, &QAction::triggered, this, member);
         menu->addAction(action);
 
diff --git a/examples/widgets/tools/plugandpaint/app/mainwindow.h b/examples/widgets/tools/plugandpaint/app/mainwindow.h
index 7d2c085c23..2b54264893 100644
--- a/examples/widgets/tools/plugandpaint/app/mainwindow.h
+++ b/examples/widgets/tools/plugandpaint/app/mainwindow.h
@@ -89,27 +89,27 @@ private:
     void loadPlugins();
     void populateMenus(QObject *plugin);
     void addToMenu(QObject *plugin, const QStringList &texts, QMenu *menu,
-                   Member member, QActionGroup *actionGroup = 0);
+                   Member member, QActionGroup *actionGroup = nullptr);
 
-    PaintArea *paintArea;
-    QScrollArea *scrollArea;
+    PaintArea *paintArea = nullptr;
+    QScrollArea *scrollArea = nullptr;
     QDir pluginsDir;
     QStringList pluginFileNames;
 
-    QMenu *fileMenu;
-    QMenu *brushMenu;
-    QMenu *shapesMenu;
-    QMenu *filterMenu;
-    QMenu *helpMenu;
-    QActionGroup *brushActionGroup;
-    QAction *openAct;
-    QAction *saveAsAct;
-    QAction *exitAct;
-    QAction *brushWidthAct;
-    QAction *brushColorAct;
-    QAction *aboutAct;
-    QAction *aboutQtAct;
-    QAction *aboutPluginsAct;
+    QMenu *fileMenu = nullptr;
+    QMenu *brushMenu = nullptr;
+    QMenu *shapesMenu = nullptr;
+    QMenu *filterMenu = nullptr;
+    QMenu *helpMenu = nullptr;
+    QActionGroup *brushActionGroup = nullptr;
+    QAction *openAct = nullptr;
+    QAction *saveAsAct = nullptr;
+    QAction *exitAct = nullptr;
+    QAction *brushWidthAct = nullptr;
+    QAction *brushColorAct = nullptr;
+    QAction *aboutAct = nullptr;
+    QAction *aboutQtAct = nullptr;
+    QAction *aboutPluginsAct = nullptr;
 };
 
 #endif
diff --git a/examples/widgets/tools/plugandpaint/app/paintarea.cpp b/examples/widgets/tools/plugandpaint/app/paintarea.cpp
index 5d2170bfd4..4295e04cc0 100644
--- a/examples/widgets/tools/plugandpaint/app/paintarea.cpp
+++ b/examples/widgets/tools/plugandpaint/app/paintarea.cpp
@@ -52,16 +52,11 @@
 #include "interfaces.h"
 #include "paintarea.h"
 
-#include <QPainter>
 #include <QMouseEvent>
+#include <QPainter>
 
 PaintArea::PaintArea(QWidget *parent) :
-    QWidget(parent),
-    theImage(500, 400, QImage::Format_RGB32),
-    color(Qt::blue),
-    thickness(3),
-    brushInterface(0),
-    lastPos(-1, -1)
+    QWidget(parent)
 {
     setAttribute(Qt::WA_StaticContents);
     setAttribute(Qt::WA_NoBackground);
diff --git a/examples/widgets/tools/plugandpaint/app/paintarea.h b/examples/widgets/tools/plugandpaint/app/paintarea.h
index 1c8ee1ee1b..1d1e6006c8 100644
--- a/examples/widgets/tools/plugandpaint/app/paintarea.h
+++ b/examples/widgets/tools/plugandpaint/app/paintarea.h
@@ -63,7 +63,7 @@ class PaintArea : public QWidget
     Q_OBJECT
 
 public:
-    PaintArea(QWidget *parent = 0);
+    PaintArea(QWidget *parent = nullptr);
 
     bool openImage(const QString &fileName);
     bool saveImage(const QString &fileName, const char *fileFormat);
@@ -87,13 +87,13 @@ protected:
 private:
     void setupPainter(QPainter &painter);
 
-    QImage theImage;
-    QColor color;
-    int thickness;
+    QImage theImage = {500, 400, QImage::Format_RGB32};
+    QColor color = Qt::blue;
+    int thickness = 3;
 
-    BrushInterface *brushInterface;
+    BrushInterface *brushInterface = nullptr;
     QString brush;
-    QPoint lastPos;
+    QPoint lastPos = {-1, -1};
 
     QPainterPath pendingPath;
 };
diff --git a/examples/widgets/tools/plugandpaint/app/plugindialog.cpp b/examples/widgets/tools/plugandpaint/app/plugindialog.cpp
index 43eb34f423..af5828f67e 100644
--- a/examples/widgets/tools/plugandpaint/app/plugindialog.cpp
+++ b/examples/widgets/tools/plugandpaint/app/plugindialog.cpp
@@ -52,16 +52,15 @@
 #include "interfaces.h"
 #include "plugindialog.h"
 
-#include <QPluginLoader>
-#include <QStringList>
 #include <QDir>
-
-#include <QLabel>
 #include <QGridLayout>
+#include <QHeaderView>
+#include <QLabel>
+#include <QPluginLoader>
 #include <QPushButton>
+#include <QStringList>
 #include <QTreeWidget>
 #include <QTreeWidgetItem>
-#include <QHeaderView>
 
 PluginDialog::PluginDialog(const QString &path, const QStringList &fileNames,
                            QWidget *parent) :
@@ -107,11 +106,12 @@ void PluginDialog::findPlugins(const QString &path,
 
     const QDir dir(path);
 
-    foreach (QObject *plugin, QPluginLoader::staticInstances())
+    const auto staticInstances = QPluginLoader::staticInstances();
+    for (QObject *plugin : staticInstances)
         populateTreeWidget(plugin, tr("%1 (Static Plugin)")
                                    .arg(plugin->metaObject()->className()));
 
-    foreach (QString fileName, fileNames) {
+    for (const QString &fileName : fileNames) {
         QPluginLoader loader(dir.absoluteFilePath(fileName));
         QObject *plugin = loader.instance();
         if (plugin)
@@ -123,7 +123,7 @@ void PluginDialog::findPlugins(const QString &path,
 //! [1]
 void PluginDialog::populateTreeWidget(QObject *plugin, const QString &text)
 {
-    QTreeWidgetItem *pluginItem = new QTreeWidgetItem(treeWidget);
+    auto pluginItem = new QTreeWidgetItem(treeWidget);
     pluginItem->setText(0, text);
     treeWidget->setItemExpanded(pluginItem, true);
 
@@ -132,16 +132,15 @@ void PluginDialog::populateTreeWidget(QObject *plugin, const QString &text)
     pluginItem->setFont(0, boldFont);
 
     if (plugin) {
-        BrushInterface *iBrush = qobject_cast<BrushInterface *>(plugin);
+        auto iBrush = qobject_cast<BrushInterface *>(plugin);
         if (iBrush)
             addItems(pluginItem, "BrushInterface", iBrush->brushes());
 
-        ShapeInterface *iShape = qobject_cast<ShapeInterface *>(plugin);
+        auto iShape = qobject_cast<ShapeInterface *>(plugin);
         if (iShape)
             addItems(pluginItem, "ShapeInterface", iShape->shapes());
 
-        FilterInterface *iFilter =
-                qobject_cast<FilterInterface *>(plugin);
+        auto iFilter = qobject_cast<FilterInterface *>(plugin);
         if (iFilter)
             addItems(pluginItem, "FilterInterface", iFilter->filters());
     }
@@ -152,14 +151,14 @@ void PluginDialog::addItems(QTreeWidgetItem *pluginItem,
                             const char *interfaceName,
                             const QStringList &features)
 {
-    QTreeWidgetItem *interfaceItem = new QTreeWidgetItem(pluginItem);
+    auto interfaceItem = new QTreeWidgetItem(pluginItem);
     interfaceItem->setText(0, interfaceName);
     interfaceItem->setIcon(0, interfaceIcon);
 
-    foreach (QString feature, features) {
+    for (QString feature : features) {
         if (feature.endsWith("..."))
             feature.chop(3);
-        QTreeWidgetItem *featureItem = new QTreeWidgetItem(interfaceItem);
+        auto featureItem = new QTreeWidgetItem(interfaceItem);
         featureItem->setText(0, feature);
         featureItem->setIcon(0, featureIcon);
     }
diff --git a/examples/widgets/tools/plugandpaint/app/plugindialog.h b/examples/widgets/tools/plugandpaint/app/plugindialog.h
index f8e5bcda24..b18b30e62c 100644
--- a/examples/widgets/tools/plugandpaint/app/plugindialog.h
+++ b/examples/widgets/tools/plugandpaint/app/plugindialog.h
@@ -68,7 +68,7 @@ class PluginDialog : public QDialog
 
 public:
     PluginDialog(const QString &path, const QStringList &fileNames,
-                 QWidget *parent = 0);
+                 QWidget *parent = nullptr);
 
 private:
     void findPlugins(const QString &path, const QStringList &fileNames);
@@ -76,9 +76,9 @@ private:
     void addItems(QTreeWidgetItem *pluginItem, const char *interfaceName,
                   const QStringList &features);
 
-    QLabel *label;
-    QTreeWidget *treeWidget;
-    QPushButton *okButton;
+    QLabel *label = nullptr;
+    QTreeWidget *treeWidget = nullptr;
+    QPushButton *okButton = nullptr;
     QIcon interfaceIcon;
     QIcon featureIcon;
 };
diff --git a/examples/widgets/tools/plugandpaint/plugins/basictools/basictoolsplugin.cpp b/examples/widgets/tools/plugandpaint/plugins/basictools/basictoolsplugin.cpp
index 92620ddd8c..3b465565ba 100644
--- a/examples/widgets/tools/plugandpaint/plugins/basictools/basictoolsplugin.cpp
+++ b/examples/widgets/tools/plugandpaint/plugins/basictools/basictoolsplugin.cpp
@@ -48,18 +48,17 @@
 **
 ****************************************************************************/
 
+#include "basictoolsplugin.h"
+
+#include <QtMath>
 #include <QtWidgets>
 
-#include <qmath.h>
 #include <stdlib.h>
 
-#include "basictoolsplugin.h"
-
 //! [0]
 QStringList BasicToolsPlugin::brushes() const
 {
-    return QStringList() << tr("Pencil") << tr("Air Brush")
-                         << tr("Random Letters");
+    return {tr("Pencil"), tr("Air Brush"), tr("Random Letters")};
 }
 //! [0]
 
@@ -132,7 +131,7 @@ QRect BasicToolsPlugin::mouseRelease(const QString & /* brush */,
 //! [5]
 QStringList BasicToolsPlugin::shapes() const
 {
-    return QStringList() << tr("Circle") << tr("Star") << tr("Text...");
+    return {tr("Circle"), tr("Star"), tr("Text...")};
 }
 //! [5]
 
@@ -169,8 +168,7 @@ QPainterPath BasicToolsPlugin::generateShape(const QString &shape,
 //! [7]
 QStringList BasicToolsPlugin::filters() const
 {
-    return QStringList() << tr("Invert Pixels") << tr("Swap RGB")
-                         << tr("Grayscale");
+    return {tr("Invert Pixels"), tr("Swap RGB"), tr("Grayscale")};
 }
 //! [7]
 
@@ -187,7 +185,7 @@ QImage BasicToolsPlugin::filterImage(const QString &filter, const QImage &image,
     } else if (filter == tr("Grayscale")) {
         for (int y = 0; y < result.height(); ++y) {
             for (int x = 0; x < result.width(); ++x) {
-                int pixel = result.pixel(x, y);
+                QRgb pixel = result.pixel(x, y);
                 int gray = qGray(pixel);
                 int alpha = qAlpha(pixel);
                 result.setPixel(x, y, qRgba(gray, gray, gray, alpha));
diff --git a/examples/widgets/tools/plugandpaint/plugins/extrafilters/extrafiltersplugin.cpp b/examples/widgets/tools/plugandpaint/plugins/extrafilters/extrafiltersplugin.cpp
index 8f59afa759..48717e34f6 100644
--- a/examples/widgets/tools/plugandpaint/plugins/extrafilters/extrafiltersplugin.cpp
+++ b/examples/widgets/tools/plugandpaint/plugins/extrafilters/extrafiltersplugin.cpp
@@ -48,17 +48,17 @@
 **
 ****************************************************************************/
 
+#include "extrafiltersplugin.h"
+
 #include <QtWidgets>
 
 #include <math.h>
 #include <stdlib.h>
 
-#include "extrafiltersplugin.h"
-
 QStringList ExtraFiltersPlugin::filters() const
 {
-    return QStringList() << tr("Flip Horizontally") << tr("Flip Vertically")
-                         << tr("Smudge...") << tr("Threshold...");
+    return {tr("Flip Horizontally"), tr("Flip Vertically"),
+            tr("Smudge..."), tr("Threshold...")};
 }
 
 QImage ExtraFiltersPlugin::filterImage(const QString &filter,
@@ -70,14 +70,14 @@ QImage ExtraFiltersPlugin::filterImage(const QString &filter,
     if (filter == tr("Flip Horizontally")) {
         for (int y = 0; y < original.height(); ++y) {
             for (int x = 0; x < original.width(); ++x) {
-                int pixel = original.pixel(original.width() - x - 1, y);
+                QRgb pixel = original.pixel(original.width() - x - 1, y);
                 result.setPixel(x, y, pixel);
             }
         }
     } else if (filter == tr("Flip Vertically")) {
         for (int y = 0; y < original.height(); ++y) {
             for (int x = 0; x < original.width(); ++x) {
-                int pixel = original.pixel(x, original.height() - y - 1);
+                QRgb pixel = original.pixel(x, original.height() - y - 1);
                 result.setPixel(x, y, pixel);
             }
         }
@@ -90,11 +90,11 @@ QImage ExtraFiltersPlugin::filterImage(const QString &filter,
             for (int i = 0; i < numIters; ++i) {
                 for (int y = 1; y < original.height() - 1; ++y) {
                     for (int x = 1; x < original.width() - 1; ++x) {
-                        int p1 = original.pixel(x, y);
-                        int p2 = original.pixel(x, y + 1);
-                        int p3 = original.pixel(x, y - 1);
-                        int p4 = original.pixel(x + 1, y);
-                        int p5 = original.pixel(x - 1, y);
+                        QRgb p1 = original.pixel(x, y);
+                        QRgb p2 = original.pixel(x, y + 1);
+                        QRgb p3 = original.pixel(x, y - 1);
+                        QRgb p4 = original.pixel(x + 1, y);
+                        QRgb p5 = original.pixel(x - 1, y);
 
                         int red = (qRed(p1) + qRed(p2) + qRed(p3) + qRed(p4)
                                    + qRed(p5)) / 5;
@@ -119,7 +119,7 @@ QImage ExtraFiltersPlugin::filterImage(const QString &filter,
             int factor = 256 / threshold;
             for (int y = 0; y < original.height(); ++y) {
                 for (int x = 0; x < original.width(); ++x) {
-                    int pixel = original.pixel(x, y);
+                    QRgb pixel = original.pixel(x, y);
                     result.setPixel(x, y, qRgba(qRed(pixel) / factor * factor,
                                                 qGreen(pixel) / factor * factor,
                                                 qBlue(pixel) / factor * factor,