7 files changed, 1006 insertions, 0 deletions
diff --git a/src/plugins/platformthemes/gtk3/gtk3.json b/src/plugins/platformthemes/gtk3/gtk3.json
new file mode 100644
index 0000000000..3887248353
--- /dev/null
+++ b/src/plugins/platformthemes/gtk3/gtk3.json
@@ -0,0 +1,3 @@
+{
+    "Keys": [ "gtk3" ]
+}
diff --git a/src/plugins/platformthemes/gtk3/gtk3.pro b/src/plugins/platformthemes/gtk3/gtk3.pro
new file mode 100644
index 0000000000..cd19e73ed8
--- /dev/null
+++ b/src/plugins/platformthemes/gtk3/gtk3.pro
@@ -0,0 +1,21 @@
+TARGET = qgtk3
+
+PLUGIN_TYPE = platformthemes
+PLUGIN_EXTENDS = -
+PLUGIN_CLASS_NAME = QGtk3ThemePlugin
+load(qt_plugin)
+
+QT += core-private gui-private platformsupport-private
+
+CONFIG += X11
+QMAKE_CXXFLAGS += $$QT_CFLAGS_QGTK3
+LIBS += $$QT_LIBS_QGTK3
+
+HEADERS += \
+        qgtk3dialoghelpers.h \
+        qgtk3theme.h
+
+SOURCES += \
+        main.cpp \
+        qgtk3dialoghelpers.cpp \
+        qgtk3theme.cpp
diff --git a/src/plugins/platformthemes/gtk3/main.cpp b/src/plugins/platformthemes/gtk3/main.cpp
new file mode 100644
index 0000000000..c3e81b18e3
--- /dev/null
+++ b/src/plugins/platformthemes/gtk3/main.cpp
@@ -0,0 +1,59 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <qpa/qplatformthemeplugin.h>
+#include "qgtk3theme.h"
+
+QT_BEGIN_NAMESPACE
+
+class QGtk3ThemePlugin : public QPlatformThemePlugin
+{
+   Q_OBJECT
+   Q_PLUGIN_METADATA(IID QPlatformThemeFactoryInterface_iid FILE "gtk3.json")
+
+public:
+    QPlatformTheme *create(const QString &key, const QStringList &params) Q_DECL_OVERRIDE;
+};
+
+QPlatformTheme *QGtk3ThemePlugin::create(const QString &key, const QStringList &params)
+{
+    Q_UNUSED(params);
+    if (!key.compare(QLatin1String(QGtk3Theme::name), Qt::CaseInsensitive))
+        return new QGtk3Theme;
+
+    return 0;
+}
+
+QT_END_NAMESPACE
+
+#include "main.moc"
diff --git a/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp b/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp
new file mode 100644
index 0000000000..2a3585464f
--- /dev/null
+++ b/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp
@@ -0,0 +1,587 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qgtk3dialoghelpers.h"
+
+#include <qeventloop.h>
+#include <qwindow.h>
+#include <qcolor.h>
+#include <qdebug.h>
+#include <qfont.h>
+
+#include <private/qguiapplication_p.h>
+#include <qpa/qplatformfontdatabase.h>
+
+#undef signals
+#include <gtk/gtk.h>
+#include <gdk/gdk.h>
+#include <gdk/gdkx.h>
+#include <pango/pango.h>
+
+QT_BEGIN_NAMESPACE
+
+class QGtk3Dialog : public QWindow
+{
+    Q_OBJECT
+
+public:
+    QGtk3Dialog(GtkWidget *gtkWidget);
+    ~QGtk3Dialog();
+
+    GtkDialog *gtkDialog() const;
+
+    void exec();
+    bool show(Qt::WindowFlags flags, Qt::WindowModality modality, QWindow *parent);
+    void hide();
+
+Q_SIGNALS:
+    void accept();
+    void reject();
+
+protected:
+    static void onResponse(QGtk3Dialog *dialog, int response);
+
+private:
+    GtkWidget *gtkWidget;
+};
+
+QGtk3Dialog::QGtk3Dialog(GtkWidget *gtkWidget) : gtkWidget(gtkWidget)
+{
+    g_signal_connect_swapped(G_OBJECT(gtkWidget), "response", G_CALLBACK(onResponse), this);
+    g_signal_connect(G_OBJECT(gtkWidget), "delete-event", G_CALLBACK(gtk_widget_hide_on_delete), NULL);
+}
+
+QGtk3Dialog::~QGtk3Dialog()
+{
+    gtk_clipboard_store(gtk_clipboard_get(GDK_SELECTION_CLIPBOARD));
+    gtk_widget_destroy(gtkWidget);
+}
+
+GtkDialog *QGtk3Dialog::gtkDialog() const
+{
+    return GTK_DIALOG(gtkWidget);
+}
+
+void QGtk3Dialog::exec()
+{
+    if (modality() == Qt::ApplicationModal) {
+        // block input to the whole app, including other GTK dialogs
+        gtk_dialog_run(gtkDialog());
+    } else {
+        // block input to the window, allow input to other GTK dialogs
+        QEventLoop loop;
+        connect(this, SIGNAL(accept()), &loop, SLOT(quit()));
+        connect(this, SIGNAL(reject()), &loop, SLOT(quit()));
+        loop.exec();
+    }
+}
+
+bool QGtk3Dialog::show(Qt::WindowFlags flags, Qt::WindowModality modality, QWindow *parent)
+{
+    setParent(parent);
+    setFlags(flags);
+    setModality(modality);
+
+    gtk_widget_realize(gtkWidget); // creates X window
+
+    GdkWindow *gdkWindow = gtk_widget_get_window(gtkWidget);
+    if (parent) {
+        GdkDisplay *gdkDisplay = gdk_window_get_display(gdkWindow);
+        XSetTransientForHint(gdk_x11_display_get_xdisplay(gdkDisplay),
+                             gdk_x11_window_get_xid(gdkWindow),
+                             parent->winId());
+    }
+
+    if (modality != Qt::NonModal) {
+        gdk_window_set_modal_hint(gdkWindow, true);
+        QGuiApplicationPrivate::showModalWindow(this);
+    }
+
+    gtk_widget_show(gtkWidget);
+    gdk_window_focus(gdkWindow, GDK_CURRENT_TIME);
+    return true;
+}
+
+void QGtk3Dialog::hide()
+{
+    QGuiApplicationPrivate::hideModalWindow(this);
+    gtk_widget_hide(gtkWidget);
+}
+
+void QGtk3Dialog::onResponse(QGtk3Dialog *dialog, int response)
+{
+    if (response == GTK_RESPONSE_OK)
+        emit dialog->accept();
+    else
+        emit dialog->reject();
+}
+
+QGtk3ColorDialogHelper::QGtk3ColorDialogHelper()
+{
+    d.reset(new QGtk3Dialog(gtk_color_chooser_dialog_new("", 0)));
+    connect(d.data(), SIGNAL(accept()), this, SLOT(onAccepted()));
+    connect(d.data(), SIGNAL(reject()), this, SIGNAL(reject()));
+
+    g_signal_connect_swapped(d->gtkDialog(), "color-activated", G_CALLBACK(onColorChanged), this);
+}
+
+QGtk3ColorDialogHelper::~QGtk3ColorDialogHelper()
+{
+}
+
+bool QGtk3ColorDialogHelper::show(Qt::WindowFlags flags, Qt::WindowModality modality, QWindow *parent)
+{
+    applyOptions();
+    return d->show(flags, modality, parent);
+}
+
+void QGtk3ColorDialogHelper::exec()
+{
+    d->exec();
+}
+
+void QGtk3ColorDialogHelper::hide()
+{
+    d->hide();
+}
+
+void QGtk3ColorDialogHelper::setCurrentColor(const QColor &color)
+{
+    GtkDialog *gtkDialog = d->gtkDialog();
+    if (color.alpha() < 255)
+        gtk_color_chooser_set_use_alpha(GTK_COLOR_CHOOSER(gtkDialog), true);
+    GdkRGBA gdkColor;
+    gdkColor.red = color.redF();
+    gdkColor.green = color.greenF();
+    gdkColor.blue = color.blueF();
+    gdkColor.alpha = color.alphaF();
+    gtk_color_chooser_set_rgba(GTK_COLOR_CHOOSER(gtkDialog), &gdkColor);
+}
+
+QColor QGtk3ColorDialogHelper::currentColor() const
+{
+    GtkDialog *gtkDialog = d->gtkDialog();
+    GdkRGBA gdkColor;
+    gtk_color_chooser_get_rgba(GTK_COLOR_CHOOSER(gtkDialog), &gdkColor);
+    return QColor::fromRgbF(gdkColor.red, gdkColor.green, gdkColor.blue, gdkColor.alpha);
+}
+
+void QGtk3ColorDialogHelper::onAccepted()
+{
+    emit accept();
+    emit colorSelected(currentColor());
+}
+
+void QGtk3ColorDialogHelper::onColorChanged(QGtk3ColorDialogHelper *dialog)
+{
+    emit dialog->currentColorChanged(dialog->currentColor());
+}
+
+void QGtk3ColorDialogHelper::applyOptions()
+{
+    GtkDialog *gtkDialog = d->gtkDialog();
+    gtk_window_set_title(GTK_WINDOW(gtkDialog), options()->windowTitle().toUtf8());
+
+    gtk_color_chooser_set_use_alpha(GTK_COLOR_CHOOSER(gtkDialog), options()->testOption(QColorDialogOptions::ShowAlphaChannel));
+}
+
+QGtk3FileDialogHelper::QGtk3FileDialogHelper()
+{
+    d.reset(new QGtk3Dialog(gtk_file_chooser_dialog_new("", 0,
+                                                        GTK_FILE_CHOOSER_ACTION_OPEN,
+                                                        GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
+                                                        GTK_STOCK_OK, GTK_RESPONSE_OK, NULL)));
+    connect(d.data(), SIGNAL(accept()), this, SLOT(onAccepted()));
+    connect(d.data(), SIGNAL(reject()), this, SIGNAL(reject()));
+
+    g_signal_connect(GTK_FILE_CHOOSER(d->gtkDialog()), "selection-changed", G_CALLBACK(onSelectionChanged), this);
+    g_signal_connect_swapped(GTK_FILE_CHOOSER(d->gtkDialog()), "current-folder-changed", G_CALLBACK(onCurrentFolderChanged), this);
+}
+
+QGtk3FileDialogHelper::~QGtk3FileDialogHelper()
+{
+}
+
+bool QGtk3FileDialogHelper::show(Qt::WindowFlags flags, Qt::WindowModality modality, QWindow *parent)
+{
+    _dir.clear();
+    _selection.clear();
+
+    applyOptions();
+    return d->show(flags, modality, parent);
+}
+
+void QGtk3FileDialogHelper::exec()
+{
+    d->exec();
+}
+
+void QGtk3FileDialogHelper::hide()
+{
+    // After GtkFileChooserDialog has been hidden, gtk_file_chooser_get_current_folder()
+    // & gtk_file_chooser_get_filenames() will return bogus values -> cache the actual
+    // values before hiding the dialog
+    _dir = directory();
+    _selection = selectedFiles();
+
+    d->hide();
+}
+
+bool QGtk3FileDialogHelper::defaultNameFilterDisables() const
+{
+    return false;
+}
+
+void QGtk3FileDialogHelper::setDirectory(const QUrl &directory)
+{
+    GtkDialog *gtkDialog = d->gtkDialog();
+    gtk_file_chooser_set_current_folder(GTK_FILE_CHOOSER(gtkDialog), directory.toLocalFile().toUtf8());
+}
+
+QUrl QGtk3FileDialogHelper::directory() const
+{
+    // While GtkFileChooserDialog is hidden, gtk_file_chooser_get_current_folder()
+    // returns a bogus value -> return the cached value before hiding
+    if (!_dir.isEmpty())
+        return _dir;
+
+    QString ret;
+    GtkDialog *gtkDialog = d->gtkDialog();
+    gchar *folder = gtk_file_chooser_get_current_folder(GTK_FILE_CHOOSER(gtkDialog));
+    if (folder) {
+        ret = QString::fromUtf8(folder);
+        g_free(folder);
+    }
+    return QUrl::fromLocalFile(ret);
+}
+
+void QGtk3FileDialogHelper::selectFile(const QUrl &filename)
+{
+    GtkDialog *gtkDialog = d->gtkDialog();
+    if (options()->acceptMode() == QFileDialogOptions::AcceptSave) {
+        QFileInfo fi(filename.toLocalFile());
+        gtk_file_chooser_set_current_folder(GTK_FILE_CHOOSER(gtkDialog), fi.path().toUtf8());
+        gtk_file_chooser_set_current_name(GTK_FILE_CHOOSER(gtkDialog), fi.fileName().toUtf8());
+    } else {
+        gtk_file_chooser_select_filename(GTK_FILE_CHOOSER(gtkDialog), filename.toLocalFile().toUtf8());
+    }
+}
+
+QList<QUrl> QGtk3FileDialogHelper::selectedFiles() const
+{
+    // While GtkFileChooserDialog is hidden, gtk_file_chooser_get_filenames()
+    // returns a bogus value -> return the cached value before hiding
+    if (!_selection.isEmpty())
+        return _selection;
+
+    QList<QUrl> selection;
+    GtkDialog *gtkDialog = d->gtkDialog();
+    GSList *filenames = gtk_file_chooser_get_filenames(GTK_FILE_CHOOSER(gtkDialog));
+    for (GSList *it  = filenames; it; it = it->next)
+        selection += QUrl::fromLocalFile(QString::fromUtf8((const char*)it->data));
+    g_slist_free(filenames);
+    return selection;
+}
+
+void QGtk3FileDialogHelper::setFilter()
+{
+    applyOptions();
+}
+
+void QGtk3FileDialogHelper::selectNameFilter(const QString &filter)
+{
+    GtkFileFilter *gtkFilter = _filters.value(filter);
+    if (gtkFilter) {
+        GtkDialog *gtkDialog = d->gtkDialog();
+        gtk_file_chooser_set_filter(GTK_FILE_CHOOSER(gtkDialog), gtkFilter);
+    }
+}
+
+QString QGtk3FileDialogHelper::selectedNameFilter() const
+{
+    GtkDialog *gtkDialog = d->gtkDialog();
+    GtkFileFilter *gtkFilter = gtk_file_chooser_get_filter(GTK_FILE_CHOOSER(gtkDialog));
+    return _filterNames.value(gtkFilter);
+}
+
+void QGtk3FileDialogHelper::onAccepted()
+{
+    emit accept();
+
+    QString filter = selectedNameFilter();
+    if (filter.isEmpty())
+        emit filterSelected(filter);
+
+    QList<QUrl> files = selectedFiles();
+    emit filesSelected(files);
+    if (files.count() == 1)
+        emit fileSelected(files.first());
+}
+
+void QGtk3FileDialogHelper::onSelectionChanged(GtkDialog *gtkDialog, QGtk3FileDialogHelper *helper)
+{
+    QString selection;
+    gchar *filename = gtk_file_chooser_get_filename(GTK_FILE_CHOOSER(gtkDialog));
+    if (filename) {
+        selection = QString::fromUtf8(filename);
+        g_free(filename);
+    }
+    emit helper->currentChanged(QUrl::fromLocalFile(selection));
+}
+
+void QGtk3FileDialogHelper::onCurrentFolderChanged(QGtk3FileDialogHelper *dialog)
+{
+    emit dialog->directoryEntered(dialog->directory());
+}
+
+static GtkFileChooserAction gtkFileChooserAction(const QSharedPointer<QFileDialogOptions> &options)
+{
+    switch (options->fileMode()) {
+    case QFileDialogOptions::AnyFile:
+    case QFileDialogOptions::ExistingFile:
+    case QFileDialogOptions::ExistingFiles:
+        if (options->acceptMode() == QFileDialogOptions::AcceptOpen)
+            return GTK_FILE_CHOOSER_ACTION_OPEN;
+        else
+            return GTK_FILE_CHOOSER_ACTION_SAVE;
+    case QFileDialogOptions::Directory:
+    case QFileDialogOptions::DirectoryOnly:
+    default:
+        if (options->acceptMode() == QFileDialogOptions::AcceptOpen)
+            return GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER;
+        else
+            return GTK_FILE_CHOOSER_ACTION_CREATE_FOLDER;
+    }
+}
+
+void QGtk3FileDialogHelper::applyOptions()
+{
+    GtkDialog *gtkDialog = d->gtkDialog();
+    const QSharedPointer<QFileDialogOptions> &opts = options();
+
+    gtk_window_set_title(GTK_WINDOW(gtkDialog), opts->windowTitle().toUtf8());
+    gtk_file_chooser_set_local_only(GTK_FILE_CHOOSER(gtkDialog), true);
+
+    const GtkFileChooserAction action = gtkFileChooserAction(opts);
+    gtk_file_chooser_set_action(GTK_FILE_CHOOSER(gtkDialog), action);
+
+    const bool selectMultiple = opts->fileMode() == QFileDialogOptions::ExistingFiles;
+    gtk_file_chooser_set_select_multiple(GTK_FILE_CHOOSER(gtkDialog), selectMultiple);
+
+    const bool confirmOverwrite = !opts->testOption(QFileDialogOptions::DontConfirmOverwrite);
+    gtk_file_chooser_set_do_overwrite_confirmation(GTK_FILE_CHOOSER(gtkDialog), confirmOverwrite);
+
+    const QStringList nameFilters = opts->nameFilters();
+    if (!nameFilters.isEmpty())
+        setNameFilters(nameFilters);
+
+    if (opts->initialDirectory().isLocalFile())
+        setDirectory(opts->initialDirectory());
+
+    foreach (const QUrl &filename, opts->initiallySelectedFiles())
+        selectFile(filename);
+
+    const QString initialNameFilter = opts->initiallySelectedNameFilter();
+    if (!initialNameFilter.isEmpty())
+        selectNameFilter(initialNameFilter);
+
+    GtkWidget *acceptButton = gtk_dialog_get_widget_for_response(gtkDialog, GTK_RESPONSE_OK);
+    if (acceptButton) {
+        if (opts->isLabelExplicitlySet(QFileDialogOptions::Accept))
+            gtk_button_set_label(GTK_BUTTON(acceptButton), opts->labelText(QFileDialogOptions::Accept).toUtf8());
+        else if (opts->acceptMode() == QFileDialogOptions::AcceptOpen)
+            gtk_button_set_label(GTK_BUTTON(acceptButton), GTK_STOCK_OPEN);
+        else
+            gtk_button_set_label(GTK_BUTTON(acceptButton), GTK_STOCK_SAVE);
+    }
+
+    GtkWidget *rejectButton = gtk_dialog_get_widget_for_response(gtkDialog, GTK_RESPONSE_CANCEL);
+    if (rejectButton) {
+        if (opts->isLabelExplicitlySet(QFileDialogOptions::Reject))
+            gtk_button_set_label(GTK_BUTTON(rejectButton), opts->labelText(QFileDialogOptions::Reject).toUtf8());
+        else
+            gtk_button_set_label(GTK_BUTTON(rejectButton), GTK_STOCK_CANCEL);
+    }
+}
+
+void QGtk3FileDialogHelper::setNameFilters(const QStringList &filters)
+{
+    GtkDialog *gtkDialog = d->gtkDialog();
+    foreach (GtkFileFilter *filter, _filters)
+        gtk_file_chooser_remove_filter(GTK_FILE_CHOOSER(gtkDialog), filter);
+
+    _filters.clear();
+    _filterNames.clear();
+
+    foreach (const QString &filter, filters) {
+        GtkFileFilter *gtkFilter = gtk_file_filter_new();
+        const QString name = filter.left(filter.indexOf(QLatin1Char('(')));
+        const QStringList extensions = cleanFilterList(filter);
+
+        gtk_file_filter_set_name(gtkFilter, name.isEmpty() ? extensions.join(QStringLiteral(", ")).toUtf8() : name.toUtf8());
+        foreach (const QString &ext, extensions)
+            gtk_file_filter_add_pattern(gtkFilter, ext.toUtf8());
+
+        gtk_file_chooser_add_filter(GTK_FILE_CHOOSER(gtkDialog), gtkFilter);
+
+        _filters.insert(filter, gtkFilter);
+        _filterNames.insert(gtkFilter, filter);
+    }
+}
+
+QGtk3FontDialogHelper::QGtk3FontDialogHelper()
+{
+    d.reset(new QGtk3Dialog(gtk_font_chooser_dialog_new("", 0)));
+    connect(d.data(), SIGNAL(accept()), this, SLOT(onAccepted()));
+    connect(d.data(), SIGNAL(reject()), this, SIGNAL(reject()));
+}
+
+QGtk3FontDialogHelper::~QGtk3FontDialogHelper()
+{
+}
+
+bool QGtk3FontDialogHelper::show(Qt::WindowFlags flags, Qt::WindowModality modality, QWindow *parent)
+{
+    applyOptions();
+    return d->show(flags, modality, parent);
+}
+
+void QGtk3FontDialogHelper::exec()
+{
+    d->exec();
+}
+
+void QGtk3FontDialogHelper::hide()
+{
+    d->hide();
+}
+
+static QString qt_fontToString(const QFont &font)
+{
+    PangoFontDescription *desc = pango_font_description_new();
+    pango_font_description_set_size(desc, font.pointSizeF() * PANGO_SCALE);
+    pango_font_description_set_family(desc, font.family().toUtf8());
+
+    int weight = font.weight();
+    if (weight >= QFont::Black)
+        pango_font_description_set_weight(desc, PANGO_WEIGHT_HEAVY);
+    else if (weight >= QFont::ExtraBold)
+        pango_font_description_set_weight(desc, PANGO_WEIGHT_ULTRABOLD);
+    else if (weight >= QFont::Bold)
+        pango_font_description_set_weight(desc, PANGO_WEIGHT_BOLD);
+    else if (weight >= QFont::DemiBold)
+        pango_font_description_set_weight(desc, PANGO_WEIGHT_SEMIBOLD);
+    else if (weight >= QFont::Medium)
+        pango_font_description_set_weight(desc, PANGO_WEIGHT_MEDIUM);
+    else if (weight >= QFont::Normal)
+        pango_font_description_set_weight(desc, PANGO_WEIGHT_NORMAL);
+    else if (weight >= QFont::Light)
+        pango_font_description_set_weight(desc, PANGO_WEIGHT_LIGHT);
+    else if (weight >= QFont::ExtraLight)
+        pango_font_description_set_weight(desc, PANGO_WEIGHT_ULTRALIGHT);
+    else
+        pango_font_description_set_weight(desc, PANGO_WEIGHT_THIN);
+
+    int style = font.style();
+    if (style == QFont::StyleItalic)
+        pango_font_description_set_style(desc, PANGO_STYLE_ITALIC);
+    else if (style == QFont::StyleOblique)
+        pango_font_description_set_style(desc, PANGO_STYLE_OBLIQUE);
+    else
+        pango_font_description_set_style(desc, PANGO_STYLE_NORMAL);
+
+    char *str = pango_font_description_to_string(desc);
+    QString name = QString::fromUtf8(str);
+    pango_font_description_free(desc);
+    g_free(str);
+    return name;
+}
+
+static QFont qt_fontFromString(const QString &name)
+{
+    QFont font;
+    PangoFontDescription *desc = pango_font_description_from_string(name.toUtf8());
+    font.setPointSizeF(static_cast<float>(pango_font_description_get_size(desc)) / PANGO_SCALE);
+
+    QString family = QString::fromUtf8(pango_font_description_get_family(desc));
+    if (!family.isEmpty())
+        font.setFamily(family);
+
+    const int weight = pango_font_description_get_weight(desc);
+    font.setWeight(QPlatformFontDatabase::weightFromInteger(weight));
+
+    PangoStyle style = pango_font_description_get_style(desc);
+    if (style == PANGO_STYLE_ITALIC)
+        font.setStyle(QFont::StyleItalic);
+    else if (style == PANGO_STYLE_OBLIQUE)
+        font.setStyle(QFont::StyleOblique);
+    else
+        font.setStyle(QFont::StyleNormal);
+
+    pango_font_description_free(desc);
+    return font;
+}
+
+void QGtk3FontDialogHelper::setCurrentFont(const QFont &font)
+{
+    GtkFontChooser *gtkDialog = GTK_FONT_CHOOSER(d->gtkDialog());
+    gtk_font_chooser_set_font(gtkDialog, qt_fontToString(font).toUtf8());
+}
+
+QFont QGtk3FontDialogHelper::currentFont() const
+{
+    GtkFontChooser *gtkDialog = GTK_FONT_CHOOSER(d->gtkDialog());
+    gchar *name = gtk_font_chooser_get_font(gtkDialog);
+    QFont font = qt_fontFromString(QString::fromUtf8(name));
+    g_free(name);
+    return font;
+}
+
+void QGtk3FontDialogHelper::onAccepted()
+{
+    emit currentFontChanged(currentFont());
+    emit accept();
+    emit fontSelected(currentFont());
+}
+
+void QGtk3FontDialogHelper::applyOptions()
+{
+    GtkDialog *gtkDialog = d->gtkDialog();
+    const QSharedPointer<QFontDialogOptions> &opts = options();
+
+    gtk_window_set_title(GTK_WINDOW(gtkDialog), opts->windowTitle().toUtf8());
+}
+
+QT_END_NAMESPACE
+
+#include "qgtk3dialoghelpers.moc"
diff --git a/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.h b/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.h
new file mode 100644
index 0000000000..438dee861b
--- /dev/null
+++ b/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.h
@@ -0,0 +1,140 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QGTK3DIALOGHELPERS_H
+#define QGTK3DIALOGHELPERS_H
+
+#include <QtCore/qhash.h>
+#include <QtCore/qlist.h>
+#include <QtCore/qurl.h>
+#include <QtCore/qscopedpointer.h>
+#include <QtCore/qstring.h>
+#include <qpa/qplatformdialoghelper.h>
+
+typedef struct _GtkDialog GtkDialog;
+typedef struct _GtkFileFilter GtkFileFilter;
+
+QT_BEGIN_NAMESPACE
+
+class QGtk3Dialog;
+class QColor;
+
+class QGtk3ColorDialogHelper : public QPlatformColorDialogHelper
+{
+    Q_OBJECT
+
+public:
+    QGtk3ColorDialogHelper();
+    ~QGtk3ColorDialogHelper();
+
+    bool show(Qt::WindowFlags flags, Qt::WindowModality modality, QWindow *parent) Q_DECL_OVERRIDE;
+    void exec() Q_DECL_OVERRIDE;
+    void hide() Q_DECL_OVERRIDE;
+
+    void setCurrentColor(const QColor &color) Q_DECL_OVERRIDE;
+    QColor currentColor() const Q_DECL_OVERRIDE;
+
+private Q_SLOTS:
+    void onAccepted();
+
+private:
+    static void onColorChanged(QGtk3ColorDialogHelper *helper);
+    void applyOptions();
+
+    QScopedPointer<QGtk3Dialog> d;
+};
+
+class QGtk3FileDialogHelper : public QPlatformFileDialogHelper
+{
+    Q_OBJECT
+
+public:
+    QGtk3FileDialogHelper();
+    ~QGtk3FileDialogHelper();
+
+    bool show(Qt::WindowFlags flags, Qt::WindowModality modality, QWindow *parent) Q_DECL_OVERRIDE;
+    void exec() Q_DECL_OVERRIDE;
+    void hide() Q_DECL_OVERRIDE;
+
+    bool defaultNameFilterDisables() const Q_DECL_OVERRIDE;
+    void setDirectory(const QUrl &directory) Q_DECL_OVERRIDE;
+    QUrl directory() const Q_DECL_OVERRIDE;
+    void selectFile(const QUrl &filename) Q_DECL_OVERRIDE;
+    QList<QUrl> selectedFiles() const Q_DECL_OVERRIDE;
+    void setFilter() Q_DECL_OVERRIDE;
+    void selectNameFilter(const QString &filter) Q_DECL_OVERRIDE;
+    QString selectedNameFilter() const Q_DECL_OVERRIDE;
+
+private Q_SLOTS:
+    void onAccepted();
+
+private:
+    static void onSelectionChanged(GtkDialog *dialog, QGtk3FileDialogHelper *helper);
+    static void onCurrentFolderChanged(QGtk3FileDialogHelper *helper);
+    void applyOptions();
+    void setNameFilters(const QStringList &filters);
+
+    QUrl _dir;
+    QList<QUrl> _selection;
+    QHash<QString, GtkFileFilter*> _filters;
+    QHash<GtkFileFilter*, QString> _filterNames;
+    QScopedPointer<QGtk3Dialog> d;
+};
+
+class QGtk3FontDialogHelper : public QPlatformFontDialogHelper
+{
+    Q_OBJECT
+
+public:
+    QGtk3FontDialogHelper();
+    ~QGtk3FontDialogHelper();
+
+    bool show(Qt::WindowFlags flags, Qt::WindowModality modality, QWindow *parent) Q_DECL_OVERRIDE;
+    void exec() Q_DECL_OVERRIDE;
+    void hide() Q_DECL_OVERRIDE;
+
+    void setCurrentFont(const QFont &font) Q_DECL_OVERRIDE;
+    QFont currentFont() const Q_DECL_OVERRIDE;
+
+private Q_SLOTS:
+    void onAccepted();
+
+private:
+    void applyOptions();
+
+    QScopedPointer<QGtk3Dialog> d;
+};
+
+QT_END_NAMESPACE
+
+#endif // QGTK3DIALOGHELPERS_H
diff --git a/src/plugins/platformthemes/gtk3/qgtk3theme.cpp b/src/plugins/platformthemes/gtk3/qgtk3theme.cpp
new file mode 100644
index 0000000000..76afc441a4
--- /dev/null
+++ b/src/plugins/platformthemes/gtk3/qgtk3theme.cpp
@@ -0,0 +1,139 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qgtk3theme.h"
+#include "qgtk3dialoghelpers.h"
+#include <QVariant>
+
+#undef signals
+#include <gtk/gtk.h>
+
+#include <X11/Xlib.h>
+
+QT_BEGIN_NAMESPACE
+
+const char *QGtk3Theme::name = "gtk3";
+
+static QString gtkSetting(const gchar *propertyName)
+{
+    GtkSettings *settings = gtk_settings_get_default();
+    gchararray value;
+    g_object_get(settings, propertyName, &value, NULL);
+    QString str = QString::fromUtf8(value);
+    g_free(value);
+    return str;
+}
+
+void gtkMessageHandler(const gchar *log_domain,
+                       GLogLevelFlags log_level,
+                       const gchar *message,
+                       gpointer unused_data) {
+    /* Silence false-positive Gtk warnings (we are using Xlib to set
+     * the WM_TRANSIENT_FOR hint).
+     */
+    if (g_strcmp0(message, "GtkDialog mapped without a transient parent. "
+                           "This is discouraged.") != 0) {
+        /* For other messages, call the default handler. */
+        g_log_default_handler(log_domain, log_level, message, unused_data);
+    }
+}
+
+QGtk3Theme::QGtk3Theme()
+{
+    // gtk_init will reset the Xlib error handler, and that causes
+    // Qt applications to quit on X errors. Therefore, we need to manually restore it.
+    int (*oldErrorHandler)(Display *, XErrorEvent *) = XSetErrorHandler(NULL);
+
+    gtk_init(0, 0);
+
+    XSetErrorHandler(oldErrorHandler);
+
+    /* Initialize some types here so that Gtk+ does not crash when reading
+     * the treemodel for GtkFontChooser.
+     */
+    g_type_ensure(PANGO_TYPE_FONT_FAMILY);
+    g_type_ensure(PANGO_TYPE_FONT_FACE);
+
+    /* Use our custom log handler. */
+    g_log_set_handler("Gtk", G_LOG_LEVEL_MESSAGE, gtkMessageHandler, NULL);
+}
+
+QVariant QGtk3Theme::themeHint(QPlatformTheme::ThemeHint hint) const
+{
+    switch (hint) {
+    case QPlatformTheme::SystemIconThemeName:
+        return QVariant(gtkSetting("gtk-icon-theme-name"));
+    case QPlatformTheme::SystemIconFallbackThemeName:
+        return QVariant(gtkSetting("gtk-fallback-icon-theme"));
+    default:
+        return QGnomeTheme::themeHint(hint);
+    }
+}
+
+QString QGtk3Theme::gtkFontName() const
+{
+    QString cfgFontName = gtkSetting("gtk-font-name");
+    if (!cfgFontName.isEmpty())
+        return cfgFontName;
+    return QGnomeTheme::gtkFontName();
+}
+
+bool QGtk3Theme::usePlatformNativeDialog(DialogType type) const
+{
+    switch (type) {
+    case ColorDialog:
+        return true;
+    case FileDialog:
+        return true;
+    case FontDialog:
+        return true;
+    default:
+        return false;
+    }
+}
+
+QPlatformDialogHelper *QGtk3Theme::createPlatformDialogHelper(DialogType type) const
+{
+    switch (type) {
+    case ColorDialog:
+        return new QGtk3ColorDialogHelper;
+    case FileDialog:
+        return new QGtk3FileDialogHelper;
+    case FontDialog:
+        return new QGtk3FontDialogHelper;
+    default:
+        return 0;
+    }
+}
+
+QT_END_NAMESPACE
diff --git a/src/plugins/platformthemes/gtk3/qgtk3theme.h b/src/plugins/platformthemes/gtk3/qgtk3theme.h
new file mode 100644
index 0000000000..1597f6e911
--- /dev/null
+++ b/src/plugins/platformthemes/gtk3/qgtk3theme.h
@@ -0,0 +1,57 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QGTK3THEME_H
+#define QGTK3THEME_H
+
+#include <private/qgenericunixthemes_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QGtk3Theme : public QGnomeTheme
+{
+public:
+    QGtk3Theme();
+
+    virtual QVariant themeHint(ThemeHint hint) const Q_DECL_OVERRIDE;
+    virtual QString gtkFontName() const Q_DECL_OVERRIDE;
+
+    bool usePlatformNativeDialog(DialogType type) const Q_DECL_OVERRIDE;
+    QPlatformDialogHelper *createPlatformDialogHelper(DialogType type) const Q_DECL_OVERRIDE;
+
+    static const char *name;
+};
+
+QT_END_NAMESPACE
+
+#endif // QGTK3THEME_H