Qt message window: horizontal scrolling

Multiple stints of flailing about without a clue finally led to
a breakthrough.  When writing a new message to the multi-line
message window, force the view back to showing the starts of
lines if player has scrolled it to the side and left it that way.
Put another way, if it has been scrolled to the right, scroll it
as far as possible back to the left.

doc/fixes37.0

@@ -1,4 +1,4 @@
-NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.366 $ $NHDT-Date: 1606504240 2020/11/27 19:10:40 $
+NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.367 $ $NHDT-Date: 1606697932 2020/11/30 00:58:52 $
 
 General Fixes and Modified Features
 -----------------------------------
@@ -500,6 +500,8 @@ Qt: don't clobber an existing save file after choosing "new game" in the
 	saved game selection widget
 Qt: don't get stuck in a loop after choosing "play" while the character name
 	field is empty in the character selection widget
+Qt: when a new message is issued, pan the message window to its left edge if
+	player panned it horizontally then didn't manually scroll it back
 Qt: {maybe just Qt+OSX:} when viewing a text window ('V' to look at 'history'
 	for instance), clicking on [Search], entering a search target in the
 	resulting popup and clicking on [Okay] or typing <return>, the text

win/Qt/qt_msg.cpp

@@ -23,9 +23,12 @@ extern "C" {
 namespace nethack_qt_ {
 
 NetHackQtMessageWindow::NetHackQtMessageWindow() :
-    list(new QListWidget())
+    list(new QListWidget()),
+    scrollarea(new QScrollArea())
 {
     list->setFocusPolicy(Qt::NoFocus);
+    scrollarea->setFocusPolicy(Qt::NoFocus);
+    scrollarea->takeWidget();
     ::iflags.window_inited = 1;
     map = 0;
     currgetmsg = 0;
@@ -39,7 +42,9 @@ NetHackQtMessageWindow::~NetHackQtMessageWindow()
     delete list;
 }
 
-QWidget* NetHackQtMessageWindow::Widget() { return list; }
+QWidget* NetHackQtMessageWindow::Widget() {
+    return list;
+}
 
 void NetHackQtMessageWindow::setMap(NetHackQtMapWindow2* m)
 {
@@ -152,6 +157,8 @@ void NetHackQtMessageWindow::PutStr(int attr, const QString& text)
             item->setBackground(bg);
         }
     }
+#else
+    nhUse(attr);
 #endif
 
     if (list->count() >= (int) ::iflags.msg_history)
@@ -163,6 +170,13 @@ void NetHackQtMessageWindow::PutStr(int attr, const QString& text)
     // selects most recent message, which causes it to be highlighted
     list->setCurrentRow(list->count() - 1);
 
+    // if message window has been scrolled right, force back to left edge
+    QScrollBar *sb = list->horizontalScrollBar();
+    if (sb && sb->value() > 0) {
+        sb->setValue(0);
+        this->viewport()->update();
+    }
+
     if (map)
 	map->putMessage(attr, text2);
 }

win/Qt/qt_msg.h

@@ -13,7 +13,7 @@ namespace nethack_qt_ {
 
 class NetHackQtMapWindow2;
 
-class NetHackQtMessageWindow : QObject, public NetHackQtWindow {
+class NetHackQtMessageWindow : QScrollArea, public NetHackQtWindow {
 	Q_OBJECT
 public:
 	NetHackQtMessageWindow();
@@ -37,8 +37,9 @@ public:
         void AddToStr(const char *answerbuf);
 
 private:
-	QListWidget* list;
-	bool changed;
+        QListWidget *list;
+        QScrollArea *scrollarea;
+        bool changed;
         int currgetmsg;
 	NetHackQtMapWindow2* map;