Polish rich text example.

- Introduce Qt 5 signals & slot syntax.
- Use mime types in the file dialogs.
- Streamline the code creating the actions.
- Introduce QCommandLineParser.
- Query the available size when determining
  the initial size instead of using hard-coded values
  for High-DPI screens.

Change-Id: Ifc84a41ed55a4a674b6eafdb6120ac42441405b6
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>

examples/widgets/richtext/textedit/main.cpp

@@ -32,15 +32,37 @@
 ****************************************************************************/
 
 #include "textedit.h"
+
 #include <QApplication>
+#include <QDesktopWidget>
+#include <QCommandLineParser>
+#include <QCommandLineOption>
 
 int main(int argc, char *argv[])
 {
     Q_INIT_RESOURCE(textedit);
 
     QApplication a(argc, argv);
+    QCoreApplication::setOrganizationName("QtProject");
+    QCoreApplication::setApplicationName("Rich Text");
+    QCoreApplication::setApplicationVersion(QT_VERSION_STR);
+    QCommandLineParser parser;
+    parser.setApplicationDescription(QCoreApplication::applicationName());
+    parser.addHelpOption();
+    parser.addVersionOption();
+    parser.addPositionalArgument("file", "The file to open.");
+    parser.process(a);
+
     TextEdit mw;
-    mw.resize(700, 800);
+
+    const QRect availableGeometry = QApplication::desktop()->availableGeometry(&mw);
+    mw.resize(availableGeometry.width() / 2, (availableGeometry.height() * 2) / 3);
+    mw.move((availableGeometry.width() - mw.width()) / 2,
+            (availableGeometry.height() - mw.height()) / 2);
+
+    if (!mw.load(parser.positionalArguments().value(0, QLatin1String(":/example.html"))))
+        mw.fileNew();
+
     mw.show();
     return a.exec();
 }

examples/widgets/richtext/textedit/textedit.h

@@ -55,19 +55,15 @@ class TextEdit : public QMainWindow
 public:
     TextEdit(QWidget *parent = 0);
 
+    bool load(const QString &f);
+
+public slots:
+    void fileNew();
+
 protected:
     virtual void closeEvent(QCloseEvent *e) Q_DECL_OVERRIDE;
 
-private:
-    void setupFileActions();
-    void setupEditActions();
-    void setupTextActions();
-    bool load(const QString &f);
-    bool maybeSave();
-    void setCurrentFileName(const QString &fileName);
-
 private slots:
-    void fileNew();
     void fileOpen();
     bool fileSave();
     bool fileSaveAs();
@@ -92,6 +88,12 @@ private slots:
     void printPreview(QPrinter *);
 
 private:
+    void setupFileActions();
+    void setupEditActions();
+    void setupTextActions();
+    bool maybeSave();
+    void setCurrentFileName(const QString &fileName);
+
     void mergeFormatOnWordOrSelection(const QTextCharFormat &format);
     void fontChanged(const QFont &f);
     void colorChanged(const QColor &c);