Use QCommandLineParser; add target directory option

When doing repeated work (or testing) into a particular output directory
it's nice to be able to specify it on the command line.

Phototonic.cpp

@@ -3298,9 +3298,11 @@ void Phototonic::createSubDirectory() {
     fileSystemTree->expand(selectedDirs[0]);
 }
 
-void Phototonic::setSaveDirectory() {
-    Settings::saveDirectory = QFileDialog::getExistingDirectory(this, tr("Directory to save images into:"),
-            QString(), QFileDialog::ShowDirsOnly | QFileDialog::DontResolveSymlinks);
+void Phototonic::setSaveDirectory(QString path) {
+    Settings::saveDirectory = path.isEmpty() ?
+        QFileDialog::getExistingDirectory(this, tr("Directory to save images into:"),
+            QString(), QFileDialog::ShowDirsOnly | QFileDialog::DontResolveSymlinks) :
+        path;
 }
 
 QString Phototonic::getSelectedPath() {

Phototonic.h

@@ -78,6 +78,8 @@ public slots:
 
     void hideViewer();
 
+    void setSaveDirectory(QString path = QString());
+
 private slots:
 
     void about();
@@ -114,8 +116,6 @@ private slots:
 
     void createSubDirectory();
 
-    void setSaveDirectory();
-
     void checkDirState(const QModelIndex &, int, int);
 
     void goSelectedDir(const QModelIndex &currDir);

main.cpp

@@ -18,29 +18,35 @@
 
 #include "Phototonic.h"
 #include <QApplication>
-
-static void showHelp() {
-    qInfo() << VERSION << "image viewer.";
-    qInfo() << "Usage: phototonic [OPTION] [FILE... | DIRECTORY]";
-    qInfo() << "  -h, --help\t\t\tshow this help and exit";
-    qInfo() << "  -l, --lang=LANGUAGE\t\tstart with a specific translation";
-}
+#include <QCommandLineParser>
 
 int main(int argc, char *argv[]) {
     QApplication QApp(argc, argv);
-    QStringList arguments = QCoreApplication::arguments();
     QLocale locale = QLocale::system();
-    int argumentsStartAt = 1;
-
-    if (arguments.size() == 2) {
-        if (arguments.at(1).startsWith("-")) {
-            showHelp();
-            return -1;
-        }
-    } else if (arguments.size() >= 3 && (arguments.at(1) == "-l" || arguments.at(1) == "--lang")) {
-        locale = QLocale(arguments.at(2));
-        argumentsStartAt = 3;
-    }
+    QCoreApplication::setApplicationVersion(VERSION);
+
+    QCommandLineParser parser;
+    parser.setApplicationDescription(VERSION " image viewer.");
+    parser.addHelpOption();
+    parser.addVersionOption();
+    parser.addPositionalArgument(QCoreApplication::translate("main", "files or directory"),
+                                 QCoreApplication::translate("main", "files or directory to open"),
+                                 QCoreApplication::translate("main", "[FILE...] | [DIRECTORY]"));
+
+    QCommandLineOption langOption(QStringList() << "l" << "lang",
+                                             QCoreApplication::translate("main", "start with a specific translation"),
+                                             QCoreApplication::translate("main", "language"));
+    parser.addOption(langOption);
+
+    QCommandLineOption targetDirectoryOption(QStringList() << "o" << "output-directory",
+            QCoreApplication::translate("main", "Copy all modified images into <directory>."),
+            QCoreApplication::translate("main", "directory"));
+    parser.addOption(targetDirectoryOption);
+
+    parser.process(QApp);
+
+    if (parser.isSet(langOption))
+        locale = QLocale(parser.value(langOption));
 
     QTranslator qTranslator;
     qTranslator.load(locale, "qt", "_", QLibraryInfo::location(QLibraryInfo::TranslationsPath));
@@ -50,8 +56,9 @@ int main(int argc, char *argv[]) {
     qTranslatorPhototonic.load(locale, "phototonic", "_", ":/translations");
     QApp.installTranslator(&qTranslatorPhototonic);
 
-    Phototonic phototonic(arguments, argumentsStartAt);
+    Phototonic phototonic(parser.positionalArguments(), 0);
+    if (parser.isSet(targetDirectoryOption))
+        phototonic.setSaveDirectory(parser.value(targetDirectoryOption));
     phototonic.show();
     return QApp.exec();
 }
-