New setting allowing to set a dark style using a style-sheet

A new setting allows to follow the system style or set a new dark style
based on a the style-sheet provided by
https://github.com/ColinDuquesnoy/QDarkStyleSheet
The style-sheet is licensed under the MIT license. Images contained in
that project are licensed under CC-BY license.

Pending issues:

- Use of stylesheets is incompatible to QPalette. Some colours for
previewing settings in the Preferences dialog are eclipsed by the style-
sheet
See https://github.com/ColinDuquesnoy/QDarkStyleSheet/issues/48

- Changing the style should select matching background and foreground
colours for the Browse Data and SQL tabs in Preferences.

See issues #1751 #1493 and #1738

CMakeLists.txt

@@ -226,6 +226,7 @@ set(SQLB_RESOURCES
 	src/translations/flags/flags.qrc
 	src/translations/translations.qrc
 	src/certs/CaCerts.qrc
+	src/qdarkstyle/style.qrc
 )
 
 set(SQLB_MISC

src/MainWindow.cpp

@@ -2364,6 +2364,24 @@ void MainWindow::reloadSettings()
     // Set data browser font
     ui->dataTable->reloadSettings();
 
+    switch (static_cast<Settings::AppStyle>(Settings::getValue("General", "appStyle").toInt())) {
+    case Settings::FollowDesktopStyle :
+        qApp->setStyleSheet("");
+
+        break;
+    case Settings::DarkStyle :
+        QFile f(":qdarkstyle/style.qss");
+        if (!f.exists()) {
+            QMessageBox::warning(this, qApp->applicationName(),
+                               tr("Could not open find resource file: %1").arg(f.fileName()));
+        } else {
+            f.open(QFile::ReadOnly | QFile::Text);
+            QTextStream ts(&f);
+            qApp->setStyleSheet(ts.readAll());
+        }
+        break;
+    }
+
     setToolButtonStyle(static_cast<Qt::ToolButtonStyle>(Settings::getValue("General", "toolbarStyle").toInt()));
     ui->dbToolbar->setToolButtonStyle(static_cast<Qt::ToolButtonStyle>(Settings::getValue("General", "toolbarStyleStructure").toInt()));
     ui->browseToolbar->setToolButtonStyle(static_cast<Qt::ToolButtonStyle>(Settings::getValue("General", "toolbarStyleBrowse").toInt()));

src/PreferencesDialog.cpp

@@ -187,6 +187,7 @@ void PreferencesDialog::loadSettings()
     ui->checkRegexDisabled->setChecked(Settings::getValue("extensions", "disableregex").toBool());
     ui->checkAllowLoadExtension->setChecked(Settings::getValue("extensions", "enable_load_extension").toBool());
     fillLanguageBox();
+    ui->appStyleCombo->setCurrentIndex(Settings::getValue("General", "appStyle").toInt());
     ui->toolbarStyleComboMain->setCurrentIndex(Settings::getValue("General", "toolbarStyle").toInt());
     ui->toolbarStyleComboStructure->setCurrentIndex(Settings::getValue("General", "toolbarStyleStructure").toInt());
     ui->toolbarStyleComboBrowse->setCurrentIndex(Settings::getValue("General", "toolbarStyleBrowse").toInt());
@@ -313,6 +314,7 @@ void PreferencesDialog::saveSettings()
                                  tr("The language will change after you restart the application."));
 
     Settings::setValue("General", "language", newLanguage);
+    Settings::setValue("General", "appStyle", ui->appStyleCombo->currentIndex());
 
     Settings::setValue("General", "toolbarStyle", ui->toolbarStyleComboMain->currentIndex());
     Settings::setValue("General", "toolbarStyleStructure", ui->toolbarStyleComboStructure->currentIndex());

src/PreferencesDialog.ui

@@ -122,7 +122,7 @@
          </property>
         </widget>
        </item>
-       <item row="2" column="0">
+       <item row="3" column="0">
         <widget class="QLabel" name="labelToolbarStyle">
          <property name="text">
           <string>Toolbar style</string>
@@ -132,7 +132,7 @@
          </property>
         </widget>
        </item>
-       <item row="4" column="1">
+       <item row="5" column="1">
         <widget class="QComboBox" name="toolbarStyleComboMain">
          <property name="sizePolicy">
           <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
@@ -182,7 +182,7 @@
          </item>
         </widget>
        </item>
-       <item row="5" column="1">
+       <item row="6" column="1">
         <widget class="QComboBox" name="toolbarStyleComboStructure">
          <property name="sizePolicy">
           <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
@@ -232,7 +232,7 @@
          </item>
         </widget>
        </item>
-       <item row="6" column="1">
+       <item row="7" column="1">
         <widget class="QComboBox" name="toolbarStyleComboBrowse">
          <property name="sizePolicy">
           <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
@@ -282,7 +282,7 @@
          </item>
         </widget>
        </item>
-       <item row="7" column="1">
+       <item row="8" column="1">
         <widget class="QComboBox" name="toolbarStyleComboSql">
          <property name="sizePolicy">
           <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
@@ -332,7 +332,7 @@
          </item>
         </widget>
        </item>
-       <item row="9" column="0">
+       <item row="10" column="0">
         <widget class="QLabel" name="labelUseRemotes">
          <property name="text">
           <string>Show remote options</string>
@@ -342,7 +342,7 @@
          </property>
         </widget>
        </item>
-       <item row="9" column="1">
+       <item row="10" column="1">
         <widget class="QCheckBox" name="checkUseRemotes">
          <property name="text">
           <string>enabled</string>
@@ -352,7 +352,7 @@
          </property>
         </widget>
        </item>
-       <item row="10" column="0">
+       <item row="11" column="0">
         <widget class="QLabel" name="labelUpdates">
          <property name="text">
           <string>Automatic &amp;updates</string>
@@ -362,14 +362,14 @@
          </property>
         </widget>
        </item>
-       <item row="10" column="1">
+       <item row="11" column="1">
         <widget class="QCheckBox" name="checkUpdates">
          <property name="text">
           <string>enabled</string>
          </property>
         </widget>
        </item>
-       <item row="11" column="0">
+       <item row="12" column="0">
         <widget class="QLabel" name="label_16">
          <property name="text">
           <string>DB file extensions</string>
@@ -379,14 +379,14 @@
          </property>
         </widget>
        </item>
-       <item row="11" column="1">
+       <item row="12" column="1">
         <widget class="QPushButton" name="buttonManageFileExtension">
          <property name="text">
           <string>Manage</string>
          </property>
         </widget>
        </item>
-       <item row="4" column="0">
+       <item row="5" column="0">
         <widget class="QLabel" name="labelMainToolBar">
          <property name="text">
           <string>Main Window</string>
@@ -399,7 +399,7 @@
          </property>
         </widget>
        </item>
-       <item row="5" column="0">
+       <item row="6" column="0">
         <widget class="QLabel" name="labelStructureToolBar">
          <property name="text">
           <string>Database Structure</string>
@@ -412,7 +412,7 @@
          </property>
         </widget>
        </item>
-       <item row="6" column="0">
+       <item row="7" column="0">
         <widget class="QLabel" name="labelBrowseToolBar">
          <property name="text">
           <string>Browse Data</string>
@@ -425,7 +425,7 @@
          </property>
         </widget>
        </item>
-       <item row="7" column="0">
+       <item row="8" column="0">
         <widget class="QLabel" name="labelSqlToolBar">
          <property name="text">
           <string>Execute SQL</string>
@@ -438,7 +438,7 @@
          </property>
         </widget>
        </item>
-       <item row="8" column="1">
+       <item row="9" column="1">
         <widget class="QComboBox" name="toolbarStyleComboEditCell">
          <property name="sizePolicy">
           <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
@@ -488,7 +488,7 @@
          </item>
         </widget>
        </item>
-       <item row="8" column="0">
+       <item row="9" column="0">
         <widget class="QLabel" name="labelEditCellToolBar">
          <property name="text">
           <string>Edit Database Cell</string>
@@ -501,6 +501,51 @@
          </property>
         </widget>
        </item>
+       <item row="2" column="1">
+        <widget class="QComboBox" name="appStyleCombo">
+         <property name="sizePolicy">
+          <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
+           <horstretch>0</horstretch>
+           <verstretch>0</verstretch>
+          </sizepolicy>
+         </property>
+         <property name="currentIndex">
+          <number>0</number>
+         </property>
+         <property name="sizeAdjustPolicy">
+          <enum>QComboBox::AdjustToContents</enum>
+         </property>
+         <property name="minimumContentsLength">
+          <number>35</number>
+         </property>
+         <property name="iconSize">
+          <size>
+           <width>20</width>
+           <height>15</height>
+          </size>
+         </property>
+         <item>
+          <property name="text">
+           <string>Follow the desktop style</string>
+          </property>
+         </item>
+         <item>
+          <property name="text">
+           <string>Dark style</string>
+          </property>
+         </item>
+        </widget>
+       </item>
+       <item row="2" column="0">
+        <widget class="QLabel" name="labelAppStyle">
+         <property name="text">
+          <string>Application style</string>
+         </property>
+         <property name="buddy">
+          <cstring>toolbarStyleComboStructure</cstring>
+         </property>
+        </widget>
+       </item>
       </layout>
      </widget>
      <widget class="QWidget" name="tab">

src/Settings.cpp

@@ -154,6 +154,10 @@ QVariant Settings::getDefaultValue(const QString& group, const QString& name)
     if(group == "General" && name == "language")
         return QLocale::system().name();
 
+    // General/appStyle
+    if(group == "General" && name == "appStyle")
+        return static_cast<int>(FollowDesktopStyle);
+
     // General/toolbarStyle
     if(group == "General" && name == "toolbarStyle")
         return static_cast<int>(Qt::ToolButtonTextBesideIcon);

src/Settings.h

@@ -9,6 +9,11 @@ class Settings
     friend class PreferencesDialog;
 
 public:
+
+    enum AppStyle {
+        FollowDesktopStyle,
+        DarkStyle
+    };
     static QVariant getValue(const QString& group, const QString& name);
     static void setValue(const QString& group, const QString& name, const QVariant& value, bool dont_save_to_disk = false);
     static void restoreDefaults();

src/qdarkstyle/style.qrc

@@ -0,0 +1,46 @@
+<RCC>
+  <qresource prefix="qss_icons">
+    <file>rc/up_arrow_disabled.png</file>
+    <file>rc/Hmovetoolbar.png</file>
+    <file>rc/stylesheet-branch-end.png</file>
+    <file>rc/branch_closed-on.png</file>
+    <file>rc/stylesheet-vline.png</file>
+    <file>rc/branch_closed.png</file>
+    <file>rc/branch_open-on.png</file>
+    <file>rc/transparent.png</file>
+    <file>rc/right_arrow_disabled.png</file>
+    <file>rc/sizegrip.png</file>
+    <file>rc/close.png</file>
+    <file>rc/close-hover.png</file>
+    <file>rc/close-pressed.png</file>
+    <file>rc/down_arrow.png</file>
+    <file>rc/Vmovetoolbar.png</file>
+    <file>rc/left_arrow.png</file>
+    <file>rc/stylesheet-branch-more.png</file>
+    <file>rc/up_arrow.png</file>
+    <file>rc/right_arrow.png</file>
+    <file>rc/left_arrow_disabled.png</file>
+    <file>rc/Hsepartoolbar.png</file>
+    <file>rc/branch_open.png</file>
+    <file>rc/Vsepartoolbar.png</file>
+    <file>rc/down_arrow_disabled.png</file>
+    <file>rc/undock.png</file>
+    <file>rc/checkbox_checked_disabled.png</file>
+    <file>rc/checkbox_checked_focus.png</file>
+    <file>rc/checkbox_checked.png</file>
+    <file>rc/checkbox_indeterminate.png</file>
+    <file>rc/checkbox_indeterminate_focus.png</file>
+    <file>rc/checkbox_unchecked_disabled.png</file>
+    <file>rc/checkbox_unchecked_focus.png</file>
+    <file>rc/checkbox_unchecked.png</file>
+    <file>rc/radio_checked_disabled.png</file>
+    <file>rc/radio_checked_focus.png</file>
+    <file>rc/radio_checked.png</file>
+    <file>rc/radio_unchecked_disabled.png</file>
+    <file>rc/radio_unchecked_focus.png</file>
+    <file>rc/radio_unchecked.png</file>
+  </qresource>
+  <qresource prefix="qdarkstyle">
+      <file>style.qss</file>
+  </qresource>
+</RCC>

src/qdarkstyle/style.qrc.depends

@@ -0,0 +1,46 @@
+<RCC>
+  <qresource prefix="qss_icons">
+    <file>rc/up_arrow_disabled.png</file>
+    <file>rc/Hmovetoolbar.png</file>
+    <file>rc/stylesheet-branch-end.png</file>
+    <file>rc/branch_closed-on.png</file>
+    <file>rc/stylesheet-vline.png</file>
+    <file>rc/branch_closed.png</file>
+    <file>rc/branch_open-on.png</file>
+    <file>rc/transparent.png</file>
+    <file>rc/right_arrow_disabled.png</file>
+    <file>rc/sizegrip.png</file>
+    <file>rc/close.png</file>
+    <file>rc/close-hover.png</file>
+    <file>rc/close-pressed.png</file>
+    <file>rc/down_arrow.png</file>
+    <file>rc/Vmovetoolbar.png</file>
+    <file>rc/left_arrow.png</file>
+    <file>rc/stylesheet-branch-more.png</file>
+    <file>rc/up_arrow.png</file>
+    <file>rc/right_arrow.png</file>
+    <file>rc/left_arrow_disabled.png</file>
+    <file>rc/Hsepartoolbar.png</file>
+    <file>rc/branch_open.png</file>
+    <file>rc/Vsepartoolbar.png</file>
+    <file>rc/down_arrow_disabled.png</file>
+    <file>rc/undock.png</file>
+    <file>rc/checkbox_checked_disabled.png</file>
+    <file>rc/checkbox_checked_focus.png</file>
+    <file>rc/checkbox_checked.png</file>
+    <file>rc/checkbox_indeterminate.png</file>
+    <file>rc/checkbox_indeterminate_focus.png</file>
+    <file>rc/checkbox_unchecked_disabled.png</file>
+    <file>rc/checkbox_unchecked_focus.png</file>
+    <file>rc/checkbox_unchecked.png</file>
+    <file>rc/radio_checked_disabled.png</file>
+    <file>rc/radio_checked_focus.png</file>
+    <file>rc/radio_checked.png</file>
+    <file>rc/radio_unchecked_disabled.png</file>
+    <file>rc/radio_unchecked_focus.png</file>
+    <file>rc/radio_unchecked.png</file>
+  </qresource>
+  <qresource prefix="qdarkstyle">
+      <file>style.qss</file>
+  </qresource>
+</RCC>

src/src.pro

@@ -126,7 +126,8 @@ SOURCES += \
 RESOURCES += icons/icons.qrc \
              translations/flags/flags.qrc \
              translations/translations.qrc \
-             certs/CaCerts.qrc
+             certs/CaCerts.qrc \
+             qdarkstyle/style.qrc
 
 FORMS += \
     MainWindow.ui \