From 97565d022303f3a4554de2c4de82ca12929dc715 Mon Sep 17 00:00:00 2001
From: Tobias Markmann <tm@ayena.de>
Date: Thu, 22 Sep 2016 23:08:57 +0200
Subject: Provide explanation for empty trellis cells to user

This shows a short descriptive text in empty trellis cells,
that describes the current state to the user and suggests
actions on how to get rid of the empty trellis cell, e.g.
by changing the layout or moving chats to the empty cells.

Test-Information:

Tested with Qt 5.5.1 on macOS 10.12.

Change-Id: Ibc7d3a327cf32b8a21304b37e79534773b5d3761

diff --git a/Swift/QtUI/QtTabWidget.cpp b/Swift/QtUI/QtTabWidget.cpp
index cda1847..67e3ae9 100644
--- a/Swift/QtUI/QtTabWidget.cpp
+++ b/Swift/QtUI/QtTabWidget.cpp
@@ -6,6 +6,10 @@
 
 #include <Swift/QtUI/QtTabWidget.h>
 
+#include <QLabel>
+#include <QPainter>
+#include <QPoint>
+
 #include <Swift/QtUI/Trellis/QtDNDTabBar.h>
 
 namespace Swift {
@@ -46,4 +50,17 @@ void QtTabWidget::dropEvent(QDropEvent* event) {
     }
 }
 
+void QtTabWidget::paintEvent(QPaintEvent * event) {
+    QTabWidget::paintEvent(event);
+    if (count() == 0) {
+        QLabel label;
+        label.setAlignment(Qt::AlignHCenter | Qt::AlignVCenter);
+        label.setGeometry(QRect(QPoint(0,0), size()) - QMargins(10,10,10,10));
+        label.setWordWrap(true);
+        label.setText(tr("This empty cell is a placeholder for chat windows. You can move existing chats to this cell by dragging the tab over here. You can change the number of cells via the 'Change layout' dialog under the 'View' menu or by using the %1 shortcut.").arg(QKeySequence(tr("Ctrl+Alt+L")).toString(QKeySequence::NativeText)));
+        QPainter painter(this);
+        painter.drawPixmap(label.geometry().topLeft(), label.grab());
+    }
+}
+
 }
diff --git a/Swift/QtUI/QtTabWidget.h b/Swift/QtUI/QtTabWidget.h
index a9d0df8..f19721d 100644
--- a/Swift/QtUI/QtTabWidget.h
+++ b/Swift/QtUI/QtTabWidget.h
@@ -21,5 +21,6 @@ namespace Swift {
         protected:
             virtual void dragEnterEvent(QDragEnterEvent* event);
             virtual void dropEvent(QDropEvent* event);
+            virtual void paintEvent(QPaintEvent* event);
     };
 }
-- 
cgit v0.10.2-6-g49f6