Polish the SVG viewer example.

- Use Qt 5 connection syntax, demonstrating lambdas.
- Use QCommandLineParser.
- Improve error handling.
- Use Mime API of QFileDialog, point to pictures location initially.
- Prevent the application from shrinking when loading small images.
- Minor polishing, status messages on loading, About Qt dialog.

Change-Id: I76f14001c9ab12cbfaaacc2ca4828b404e4b13b2
Reviewed-by: aavit <eirik.aavitsland@theqtcompany.com>

5 files changed, 102 insertions, 87 deletions

diff --git a/examples/svg/svgviewer/main.cpp b/examples/svg/svgviewer/main.cpp
index 671262c..9155c87 100644
--- a/examples/svg/svgviewer/main.cpp
+++ b/examples/svg/svgviewer/main.cpp
@@ -39,7 +39,9 @@
 ****************************************************************************/
 
 #include <QApplication>
-#include <QString>
+#include <QCommandLineParser>
+#include <QCommandLineOption>
+#include <QStringList>
 #ifndef QT_NO_OPENGL
 #include <QGLFormat>
 #endif
@@ -51,12 +53,21 @@ int main(int argc, char **argv)
     Q_INIT_RESOURCE(svgviewer);
 
     QApplication app(argc, argv);
+    QCoreApplication::setApplicationName("SVG Viewer");
+    QGuiApplication::setApplicationDisplayName(QCoreApplication::applicationName());
+    QCoreApplication::setOrganizationName("QtProject");
+    QCoreApplication::setApplicationVersion(QT_VERSION_STR);
+
+    QCommandLineParser parser;
+    parser.setApplicationDescription("Qt SVG Viewer");
+    parser.addHelpOption();
+    parser.addVersionOption();
+    parser.addPositionalArgument("file", "The file to open.");
+    parser.process(app);
 
     MainWindow window;
-    if (argc == 2)
-        window.openFile(argv[1]);
-    else
-        window.openFile(":/files/bubbles.svg");
+    if (!window.loadFile(parser.positionalArguments().value(0, QLatin1String(":/files/bubbles.svg"))))
+        return -1;
     window.show();
     return app.exec();
 }
diff --git a/examples/svg/svgviewer/mainwindow.cpp b/examples/svg/svgviewer/mainwindow.cpp
index d78c5fb..4e94642 100644
--- a/examples/svg/svgviewer/mainwindow.cpp
+++ b/examples/svg/svgviewer/mainwindow.cpp
@@ -48,47 +48,47 @@ MainWindow::MainWindow()
     : QMainWindow()
     , m_view(new SvgView)
 {
-    QMenu *fileMenu = new QMenu(tr("&File"), this);
-    QAction *openAction = fileMenu->addAction(tr("&Open..."));
-    openAction->setShortcut(QKeySequence(tr("Ctrl+O")));
-    QAction *quitAction = fileMenu->addAction(tr("E&xit"));
+    QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
+    QAction *openAction = fileMenu->addAction(tr("&Open..."), this, &MainWindow::openFile);
+    openAction->setShortcut(QKeySequence::Open);
+    QAction *quitAction = fileMenu->addAction(tr("E&xit"), qApp, QCoreApplication::quit);
     quitAction->setShortcuts(QKeySequence::Quit);
 
-    menuBar()->addMenu(fileMenu);
-
-    QMenu *viewMenu = new QMenu(tr("&View"), this);
+    QMenu *viewMenu = menuBar()->addMenu(tr("&View"));
     m_backgroundAction = viewMenu->addAction(tr("&Background"));
     m_backgroundAction->setEnabled(false);
     m_backgroundAction->setCheckable(true);
     m_backgroundAction->setChecked(false);
-    connect(m_backgroundAction, SIGNAL(toggled(bool)), m_view, SLOT(setViewBackground(bool)));
+    connect(m_backgroundAction, &QAction::toggled, m_view, &SvgView::setViewBackground);
 
     m_outlineAction = viewMenu->addAction(tr("&Outline"));
     m_outlineAction->setEnabled(false);
     m_outlineAction->setCheckable(true);
     m_outlineAction->setChecked(true);
-    connect(m_outlineAction, SIGNAL(toggled(bool)), m_view, SLOT(setViewOutline(bool)));
-
-    menuBar()->addMenu(viewMenu);
+    connect(m_outlineAction, &QAction::toggled, m_view, &SvgView::setViewOutline);
 
-    QMenu *rendererMenu = new QMenu(tr("&Renderer"), this);
+    QMenu *rendererMenu = menuBar()->addMenu(tr("&Renderer"));
     m_nativeAction = rendererMenu->addAction(tr("&Native"));
     m_nativeAction->setCheckable(true);
     m_nativeAction->setChecked(true);
+    m_nativeAction->setData(int(SvgView::Native));
 #ifndef QT_NO_OPENGL
     m_glAction = rendererMenu->addAction(tr("&OpenGL"));
     m_glAction->setCheckable(true);
+    m_glAction->setData(int(SvgView::OpenGL));
 #endif
     m_imageAction = rendererMenu->addAction(tr("&Image"));
     m_imageAction->setCheckable(true);
+    m_imageAction->setData(int(SvgView::Image));
 
-#ifndef QT_NO_OPENGL
     rendererMenu->addSeparator();
     m_highQualityAntialiasingAction = rendererMenu->addAction(tr("&High Quality Antialiasing"));
     m_highQualityAntialiasingAction->setEnabled(false);
     m_highQualityAntialiasingAction->setCheckable(true);
     m_highQualityAntialiasingAction->setChecked(false);
-    connect(m_highQualityAntialiasingAction, SIGNAL(toggled(bool)), m_view, SLOT(setHighQualityAntialiasing(bool)));
+    connect(m_highQualityAntialiasingAction, &QAction::toggled, m_view, &SvgView::setHighQualityAntialiasing);
+#ifdef QT_NO_OPENGL
+    m_highQualityAntialiasingAction->setVisible(false);
 #endif
 
     QActionGroup *rendererGroup = new QActionGroup(this);
@@ -100,64 +100,57 @@ MainWindow::MainWindow()
 
     menuBar()->addMenu(rendererMenu);
 
-    connect(openAction, SIGNAL(triggered()), this, SLOT(openFile()));
-    connect(quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
-    connect(rendererGroup, SIGNAL(triggered(QAction*)),
-            this, SLOT(setRenderer(QAction*)));
+    connect(rendererGroup, &QActionGroup::triggered,
+            [this] (QAction *a) { setRenderer(a->data().toInt()); });
+
+    QMenu *help = menuBar()->addMenu(tr("&Help"));
+    help->addAction(tr("About Qt"), qApp, &QApplication::aboutQt);
 
     setCentralWidget(m_view);
-    setWindowTitle(tr("SVG Viewer"));
 }
 
-void MainWindow::openFile(const QString &path)
+void MainWindow::openFile()
 {
-    QString fileName;
-    if (path.isNull())
-        fileName = QFileDialog::getOpenFileName(this, tr("Open SVG File"),
-                m_currentPath, "SVG files (*.svg *.svgz *.svg.gz)");
-    else
-        fileName = path;
-
-    if (!fileName.isEmpty()) {
-        QFile file(fileName);
-        if (!file.exists()) {
-            QMessageBox::critical(this, tr("Open SVG File"),
-                           QString("Could not open file '%1'.").arg(fileName));
-
-            m_outlineAction->setEnabled(false);
-            m_backgroundAction->setEnabled(false);
-            return;
-        }
-
-        m_view->openFile(file);
-
-        if (!fileName.startsWith(":/")) {
-            m_currentPath = fileName;
-            setWindowTitle(tr("%1 - SVGViewer").arg(m_currentPath));
-        }
-
-        m_outlineAction->setEnabled(true);
-        m_backgroundAction->setEnabled(true);
-
-        resize(m_view->sizeHint() + QSize(80, 80 + menuBar()->height()));
-    }
+    QFileDialog fileDialog(this);
+    fileDialog.setAcceptMode(QFileDialog::AcceptOpen);
+    fileDialog.setMimeTypeFilters(QStringList() << "image/svg+xml" << "image/svg+xml-compressed");
+    fileDialog.setWindowTitle(tr("Open SVG File"));
+    if (m_currentPath.isEmpty())
+        fileDialog.setDirectory(QStandardPaths::standardLocations(QStandardPaths::PicturesLocation).value(0, QDir::currentPath()));
+
+    while (fileDialog.exec() == QDialog::Accepted && !loadFile(fileDialog.selectedFiles().constFirst()))
+        ;
 }
 
-void MainWindow::setRenderer(QAction *action)
+bool MainWindow::loadFile(const QString &fileName)
 {
-#ifndef QT_NO_OPENGL
-    m_highQualityAntialiasingAction->setEnabled(false);
-#endif
-
-    if (action == m_nativeAction)
-        m_view->setRenderer(SvgView::Native);
-#ifndef QT_NO_OPENGL
-    else if (action == m_glAction) {
-        m_highQualityAntialiasingAction->setEnabled(true);
-        m_view->setRenderer(SvgView::OpenGL);
+    if (!QFileInfo::exists(fileName) || !m_view->openFile(fileName)) {
+        QMessageBox::critical(this, tr("Open SVG File"),
+                              QString("Could not open file '%1'.").arg(QDir::toNativeSeparators(fileName)));
+        return false;
     }
-#endif
-    else if (action == m_imageAction) {
-        m_view->setRenderer(SvgView::Image);
+
+    if (!fileName.startsWith(":/")) {
+        m_currentPath = fileName;
+        setWindowFilePath(fileName);
+        const QSize size = m_view->svgSize();
+        const QString message =
+            tr("Opened %1, %2x%3").arg(QFileInfo(fileName).fileName()).arg(size.width()).arg(size.width());
+        statusBar()->showMessage(message);
     }
+
+    m_outlineAction->setEnabled(true);
+    m_backgroundAction->setEnabled(true);
+
+    const QSize availableSize = QApplication::desktop()->availableGeometry(this).size();
+    resize(m_view->sizeHint().expandedTo(availableSize / 4) + QSize(80, 80 + menuBar()->height()));
+
+    return true;
+}
+
+void MainWindow::setRenderer(int renderMode)
+{
+
+    m_highQualityAntialiasingAction->setEnabled(renderMode == SvgView::OpenGL);
+    m_view->setRenderer(static_cast<SvgView::RendererType>(renderMode));
 }
diff --git a/examples/svg/svgviewer/mainwindow.h b/examples/svg/svgviewer/mainwindow.h
index 1c43da6..215f4a6 100644
--- a/examples/svg/svgviewer/mainwindow.h
+++ b/examples/svg/svgviewer/mainwindow.h
@@ -60,9 +60,11 @@ class MainWindow : public QMainWindow
 public:
     MainWindow();
 
+    bool loadFile(const QString &path);
+
 public slots:
-    void openFile(const QString &path = QString());
-    void setRenderer(QAction *action);
+    void openFile();
+    void setRenderer(int renderMode);
 
 private:
     QAction *m_nativeAction;
diff --git a/examples/svg/svgviewer/svgview.cpp b/examples/svg/svgviewer/svgview.cpp
index 5283bf1..dd9de1a 100644
--- a/examples/svg/svgviewer/svgview.cpp
+++ b/examples/svg/svgviewer/svgview.cpp
@@ -39,7 +39,8 @@
 ****************************************************************************/
 #include "svgview.h"
 
-#include <QFile>
+#include <QSvgRenderer>
+
 #include <QWheelEvent>
 #include <QMouseEvent>
 #include <QGraphicsRectItem>
@@ -54,9 +55,9 @@
 SvgView::SvgView(QWidget *parent)
     : QGraphicsView(parent)
     , m_renderer(Native)
-    , m_svgItem(0)
-    , m_backgroundItem(0)
-    , m_outlineItem(0)
+    , m_svgItem(nullptr)
+    , m_backgroundItem(nullptr)
+    , m_outlineItem(nullptr)
 {
     setScene(new QGraphicsScene(this));
     setTransformationAnchor(AnchorUnderMouse);
@@ -83,20 +84,26 @@ void SvgView::drawBackground(QPainter *p, const QRectF &)
     p->restore();
 }
 
-void SvgView::openFile(const QFile &file)
+QSize SvgView::svgSize() const
 {
-    if (!file.exists())
-        return;
+    return m_svgItem ? m_svgItem->boundingRect().size().toSize() : QSize();
+}
 
+bool SvgView::openFile(const QString &fileName)
+{
     QGraphicsScene *s = scene();
 
-    bool drawBackground = (m_backgroundItem ? m_backgroundItem->isVisible() : false);
-    bool drawOutline = (m_outlineItem ? m_outlineItem->isVisible() : true);
+    const bool drawBackground = (m_backgroundItem ? m_backgroundItem->isVisible() : false);
+    const bool drawOutline = (m_outlineItem ? m_outlineItem->isVisible() : true);
+
+    QScopedPointer<QGraphicsSvgItem> svgItem(new QGraphicsSvgItem(fileName));
+    if (!svgItem->renderer()->isValid())
+        return false;
 
     s->clear();
     resetTransform();
 
-    m_svgItem = new QGraphicsSvgItem(file.fileName());
+    m_svgItem = svgItem.take();
     m_svgItem->setFlags(QGraphicsItem::ItemClipsToShape);
     m_svgItem->setCacheMode(QGraphicsItem::NoCache);
     m_svgItem->setZValue(0);
@@ -120,6 +127,7 @@ void SvgView::openFile(const QFile &file)
     s->addItem(m_outlineItem);
 
     s->setSceneRect(m_outlineItem->boundingRect().adjusted(-10, -10, 10, 10));
+    return true;
 }
 
 void SvgView::setRenderer(RendererType type)
diff --git a/examples/svg/svgviewer/svgview.h b/examples/svg/svgviewer/svgview.h
index b6d1b01..41c0ca5 100644
--- a/examples/svg/svgviewer/svgview.h
+++ b/examples/svg/svgviewer/svgview.h
@@ -46,7 +46,6 @@
 QT_BEGIN_NAMESPACE
 class QWheelEvent;
 class QPaintEvent;
-class QFile;
 QT_END_NAMESPACE
 
 class SvgView : public QGraphicsView
@@ -56,11 +55,13 @@ class SvgView : public QGraphicsView
 public:
     enum RendererType { Native, OpenGL, Image };
 
-    SvgView(QWidget *parent = 0);
+    explicit SvgView(QWidget *parent = nullptr);
 
-    void openFile(const QFile &file);
+    bool openFile(const QString &fileName);
     void setRenderer(RendererType type = Native);
-    void drawBackground(QPainter *p, const QRectF &rect);
+    void drawBackground(QPainter *p, const QRectF &rect) override;
+
+    QSize svgSize() const;
 
 public slots:
     void setHighQualityAntialiasing(bool highQualityAntialiasing);
@@ -68,8 +69,8 @@ public slots:
     void setViewOutline(bool enable);
 
 protected:
-    void wheelEvent(QWheelEvent *event);
-    void paintEvent(QPaintEvent *event);
+    void wheelEvent(QWheelEvent *event) override;
+    void paintEvent(QPaintEvent *event) override;
 
 private:
     RendererType m_renderer;