Desktop: create new custom TextEdit widget for notes-field

Currently, the notes field uses a QTextEdit, which doesn't
send a signal if it goes out of focus.  But for undo of
dive-editing we don't want to create an undo object for
*every* text change.

Thus, create a custom TextEdit widget that derives from
QTextEdit and turns the focusOutEvent into a editingFinished
signal.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

desktop-widgets/CMakeLists.txt

@@ -126,6 +126,8 @@ set(SUBSURFACE_INTERFACE
 	tableview.h
 	tagwidget.cpp
 	tagwidget.h
+	textedit.cpp
+	textedit.h
 	updatemanager.cpp
 	updatemanager.h
 	usersurvey.cpp

desktop-widgets/tab-widgets/maintab.ui

@@ -454,7 +454,7 @@
                 <number>0</number>
                </property>
                <item>
-                <widget class="QTextEdit" name="notes">
+                <widget class="TextEdit" name="notes">
                  <property name="readOnly">
                   <bool>false</bool>
                  </property>
@@ -601,6 +601,11 @@
    <extends>QLineEdit</extends>
    <header>desktop-widgets/locationinformation.h</header>
   </customwidget>
+  <customwidget>
+   <class>TextEdit</class>
+   <extends>QTextEdit</extends>
+   <header>desktop-widgets/textedit.h</header>
+  </customwidget>
  </customwidgets>
  <resources>
   <include location="../../subsurface.qrc"/>

desktop-widgets/textedit.cpp

@@ -0,0 +1,7 @@
+#include "textedit.h"
+
+void TextEdit::focusOutEvent(QFocusEvent *ev)
+{
+	QTextEdit::focusOutEvent(ev);
+	emit editingFinished();
+}

desktop-widgets/textedit.h

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef TEXTEDIT_H
+#define TEXTEDIT_H
+
+#include <QTextEdit>
+
+// QTextEdit does not possess a signal that fires when the user finished
+// editing the text. This subclass therefore overrides the focusOutEvent
+// and sends the textEdited signal.
+class TextEdit : public QTextEdit {
+	Q_OBJECT
+public:
+	using QTextEdit::QTextEdit; // Make constructors of QTextEdit available
+signals:
+	void editingFinished();
+private:
+	void focusOutEvent(QFocusEvent *ev) override;
+};
+
+#endif