[calamares] Migrate the about-dialog to the debug (meta) window manager

- DebugWindowManager already manages not-really-Calamares windows
  like the Debug window, add About-Dialog to its responsibilities.
- Make about() accessible to the QML progress panel.

src/calamares/CalamaresWindow.cpp

@@ -14,9 +14,7 @@
 #include "CalamaresWindow.h"
 
 #include "Branding.h"
-#include "CalamaresAbout.h"
 #include "CalamaresConfig.h"
-#include "CalamaresVersion.h"
 #include "DebugWindow.h"
 #include "Settings.h"
 #include "ViewManager.h"
@@ -25,7 +23,6 @@
 #include "utils/Logger.h"
 #include "utils/Qml.h"
 #include "utils/Retranslator.h"
-#include "widgets/TranslationFix.h"
 
 #include <QApplication>
 #include <QBoxLayout>
@@ -34,7 +31,6 @@
 #include <QFile>
 #include <QFileInfo>
 #include <QLabel>
-#include <QMessageBox>
 #ifdef WITH_QML
 #include <QQmlContext>
 #include <QQmlEngine>
@@ -91,30 +87,6 @@ setButtonIcon( QPushButton* button, const QString& name )
     }
 }
 
-static void
-showAboutBox()
-{
-    QString title = Calamares::Settings::instance()->isSetupMode()
-        ? QCoreApplication::translate( "WelcomePage", "About %1 setup" )
-        : QCoreApplication::translate( "WelcomePage", "About %1 installer" );
-    QMessageBox mb( QMessageBox::Information,
-                    title.arg( CALAMARES_APPLICATION_NAME ),
-                    Calamares::aboutString().arg( Calamares::Branding::instance()->versionedName() ),
-                    QMessageBox::Ok,
-                    nullptr );
-    Calamares::fixButtonLabels( &mb );
-    mb.setIconPixmap( CalamaresUtils::defaultPixmap(
-        CalamaresUtils::Squid,
-        CalamaresUtils::Original,
-        QSize( CalamaresUtils::defaultFontHeight() * 6, CalamaresUtils::defaultFontHeight() * 6 ) ) );
-    QGridLayout* layout = reinterpret_cast< QGridLayout* >( mb.layout() );
-    if ( layout )
-    {
-        layout->setColumnMinimumWidth( 2, CalamaresUtils::defaultFontHeight() * 24 );
-    }
-    mb.exec();
-}
-
 static QWidget*
 getWidgetSidebar( Calamares::DebugWindowManager* debug,
                   Calamares::ViewManager* viewManager,
@@ -177,7 +149,7 @@ getWidgetSidebar( Calamares::DebugWindowManager* debug,
         extraButtons->addWidget( aboutDialog );
         aboutDialog->setFlat( true );
         aboutDialog->setCheckable( true );
-        QObject::connect( aboutDialog, &QPushButton::clicked, []() { showAboutBox(); } );
+        QObject::connect( aboutDialog, &QPushButton::clicked, debug, &Calamares::DebugWindowManager::about );
     }
     if ( debug && debug->enabled() )
     {

src/calamares/DebugWindow.cpp

@@ -12,6 +12,8 @@
 #include "ui_DebugWindow.h"
 
 #include "Branding.h"
+#include "CalamaresAbout.h"
+#include "CalamaresVersion.h"
 #include "GlobalStorage.h"
 #include "Job.h"
 #include "JobQueue.h"
@@ -19,9 +21,11 @@
 #include "VariantModel.h"
 #include "modulesystem/Module.h"
 #include "modulesystem/ModuleManager.h"
+#include "utils/CalamaresUtilsGui.h"
 #include "utils/Logger.h"
 #include "utils/Paste.h"
 #include "utils/Retranslator.h"
+#include "widgets/TranslationFix.h"
 
 #ifdef WITH_PYTHONQT
 #include "ViewManager.h"
@@ -30,6 +34,7 @@
 #include <gui/PythonQtScriptingConsole.h>
 #endif
 
+#include <QMessageBox>
 #include <QSplitter>
 #include <QStringListModel>
 #include <QTreeView>
@@ -307,5 +312,28 @@ DebugWindowManager::toggle()
     show( !m_visible );
 }
 
+void
+DebugWindowManager::about()
+{
+    QString title = Calamares::Settings::instance()->isSetupMode()
+        ? QCoreApplication::translate( "WelcomePage", "About %1 setup" )
+        : QCoreApplication::translate( "WelcomePage", "About %1 installer" );
+    QMessageBox mb( QMessageBox::Information,
+                    title.arg( CALAMARES_APPLICATION_NAME ),
+                    Calamares::aboutString().arg( Calamares::Branding::instance()->versionedName() ),
+                    QMessageBox::Ok,
+                    nullptr );
+    Calamares::fixButtonLabels( &mb );
+    mb.setIconPixmap( CalamaresUtils::defaultPixmap(
+        CalamaresUtils::Squid,
+        CalamaresUtils::Original,
+        QSize( CalamaresUtils::defaultFontHeight() * 6, CalamaresUtils::defaultFontHeight() * 6 ) ) );
+    QGridLayout* layout = reinterpret_cast< QGridLayout* >( mb.layout() );
+    if ( layout )
+    {
+        layout->setColumnMinimumWidth( 2, CalamaresUtils::defaultFontHeight() * 24 );
+    }
+    mb.exec();
+}
 
 }  // namespace Calamares

src/calamares/DebugWindow.h

@@ -49,11 +49,13 @@ private:
     std::unique_ptr< VariantModel > m_module_model;
 };
 
-/** @brief Manager for the (single) DebugWindow
+/** @brief Manager for meta-windows (Debug and About windows)
  *
  * Only one DebugWindow is expected to be around. This class manages
  * (exactly one) DebugWindow and can create and destroy it as needed.
  * It is available to the Calamares panels as object `DebugWindow`.
+ *
+ * The about() method shows a modal pop-up about Calamares.
  */
 class DebugWindowManager : public QObject
 {
@@ -79,6 +81,8 @@ public Q_SLOTS:
     void show( bool visible );
     void toggle();
 
+    void about();
+
 signals:
     void visibleChanged( bool visible );
 

src/calamares/calamares-sidebar.qml

@@ -62,6 +62,31 @@ Rectangle {
         }
 
         Rectangle {
+            id: aboutArea
+            Layout.fillWidth: true;
+            height: 35
+            Layout.alignment: Qt.AlignHCenter | Qt.AlignBottom
+            color: Branding.styleString( mouseArea.containsMouse ? Branding.SidebarTextHighlight : Branding.SidebarBackground);
+            visible: true;
+
+            MouseArea {
+                id: mouseAreaAbout
+                anchors.fill: parent;
+                cursorShape: Qt.PointingHandCursor
+                hoverEnabled: true
+                Text {
+                    anchors.verticalCenter: parent.verticalCenter;
+                    x: parent.x + 4;
+                    text: qsTr("About Calamares")
+                    color: Branding.styleString( mouseArea.containsMouse ? Branding.SidebarTextSelect : Branding.SidebarBackground );
+                    font.pointSize : 9
+                }
+
+                onClicked: debug.about()
+            }
+        }
+        Rectangle {
+            id: debugArea
             Layout.fillWidth: true;
             height: 35
             Layout.alignment: Qt.AlignHCenter | Qt.AlignBottom
@@ -69,7 +94,7 @@ Rectangle {
             visible: debug.enabled
 
             MouseArea {
-                id: mouseArea
+                id: mouseAreaDebug
                 anchors.fill: parent;
                 cursorShape: Qt.PointingHandCursor
                 hoverEnabled: true