- Create a 'Theme' pref page in which 'StyleSheet' is moved, and a secondary color pref is created.

- 'StyleSheet' combobox is removed from general and replaced by a 'Theme' combobox.
- Theme combobox triggers the pref packs of type 'Theme'.

src/Gui/DlgSettingsTheme.cpp

@@ -0,0 +1,160 @@
+/***************************************************************************
+ *   Copyright (c) 2009 Werner Mayer <wmayer[at]users.sourceforge.net>     *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  is distributed in the hope that it will be useful,      *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
+ *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "PreCompiled.h"
+#ifndef _PreComp_
+# include <QPushButton>
+#endif
+
+#include "DlgSettingsTheme.h"
+#include "ui_DlgSettingsTheme.h"
+#include "Application.h"
+#include "PreferencePackManager.h"
+
+
+using namespace Gui::Dialog;
+
+/* TRANSLATOR Gui::Dialog::DlgSettingsTheme */
+
+/**
+ *  Constructs a DlgSettingsTheme which is a child of 'parent', with the
+ *  name 'name' and widget flags set to 'f'
+ */
+DlgSettingsTheme::DlgSettingsTheme(QWidget* parent)
+    : PreferencePage(parent)
+    , ui(new Ui_DlgSettingsTheme)
+    , styleSheetChanged(false)
+{
+    ui->setupUi(this);
+
+    connect(ui->styleSheetsCombobox, qOverload<int>(&QComboBox::activated), this, &DlgSettingsTheme::onStyleSheetChanged);
+}
+
+/**
+ *  Destroys the object and frees any allocated resources
+ */
+DlgSettingsTheme::~DlgSettingsTheme()
+{
+    // no need to delete child widgets, Qt does it all for us
+}
+
+void DlgSettingsTheme::saveSettings()
+{
+    ui->ThemeSecondaryColor->onSave();
+
+    if (styleSheetChanged)
+        saveStyleSheet();
+}
+
+void DlgSettingsTheme::loadSettings()
+{
+    ui->ThemeSecondaryColor->onRestore();
+
+    loadStyleSheet();
+}
+
+void DlgSettingsTheme::saveStyleSheet()
+{
+    ParameterGrp::handle hGrp = App::GetApplication().GetParameterGroupByPath("User parameter:BaseApp/Preferences/MainWindow");
+
+    QVariant sheet = ui->styleSheetsCombobox->itemData(ui->styleSheetsCombobox->currentIndex());
+    hGrp->SetASCII("StyleSheet", (const char*)sheet.toByteArray());
+    bool tiledBackground = hGrp->GetBool("TiledBackground", false);
+    Application::Instance->setStyleSheet(sheet.toString(), tiledBackground);
+}
+
+void DlgSettingsTheme::loadStyleSheet()
+{
+    ParameterGrp::handle hGrp = App::GetApplication().GetParameterGroupByPath("User parameter:BaseApp/Preferences/MainWindow");
+
+    // List all .qss/.css files
+    QMap<QString, QString> cssFiles;
+    QDir dir;
+    QStringList filter;
+    filter << QString::fromLatin1("*.qss");
+    filter << QString::fromLatin1("*.css");
+
+    // read from user, resource and built-in directory
+    QStringList qssPaths = QDir::searchPaths(QString::fromLatin1("qss"));
+    for (const auto& qssPath : qssPaths) {
+        dir.setPath(qssPath);
+        QFileInfoList fileNames = dir.entryInfoList(filter, QDir::Files, QDir::Name);
+        for (const auto& fileName : qAsConst(fileNames)) {
+            if (cssFiles.find(fileName.baseName()) == cssFiles.end()) {
+                cssFiles[fileName.baseName()] = fileName.fileName();
+            }
+        }
+    }
+
+    // now add all unique items
+    ui->styleSheetsCombobox->clear();
+    ui->styleSheetsCombobox->addItem(tr("No style sheet"), QString::fromLatin1(""));
+    for (QMap<QString, QString>::iterator it = cssFiles.begin(); it != cssFiles.end(); ++it) {
+        ui->styleSheetsCombobox->addItem(it.key(), it.value());
+    }
+
+    QString selectedStyleSheet = QString::fromLatin1(hGrp->GetASCII("StyleSheet").c_str());
+    int index = ui->styleSheetsCombobox->findData(selectedStyleSheet);
+
+    // might be an absolute path name
+    if (index < 0 && !selectedStyleSheet.isEmpty()) {
+        QFileInfo fi(selectedStyleSheet);
+        if (fi.isAbsolute()) {
+            QString path = fi.absolutePath();
+            if (qssPaths.indexOf(path) >= 0) {
+                selectedStyleSheet = fi.fileName();
+            }
+            else {
+                selectedStyleSheet = fi.absoluteFilePath();
+                ui->styleSheetsCombobox->addItem(fi.baseName(), selectedStyleSheet);
+            }
+
+            index = ui->styleSheetsCombobox->findData(selectedStyleSheet);
+        }
+    }
+
+    if (index > -1)
+        ui->styleSheetsCombobox->setCurrentIndex(index);
+}
+
+void DlgSettingsTheme::onStyleSheetChanged(int index) {
+    Q_UNUSED(index);
+    Base::Console().Warning("Hello");
+    styleSheetChanged = true;
+}
+
+/**
+ * Sets the strings of the subwidgets using the current language.
+ */
+void DlgSettingsTheme::changeEvent(QEvent *e)
+{
+    if (e->type() == QEvent::LanguageChange) {
+        ui->retranslateUi(this);
+    }
+    else {
+        QWidget::changeEvent(e);
+    }
+}
+
+
+#include "moc_DlgSettingsTheme.cpp"
+