Simplify scrolling handling in message_out.

The newline parameter to message_out is gone. Instead, a
pointer to the message line is passed which may lie outside
the message window. The window is then scrolled to make
that line the last line.

This also updates libnonunix.cc, but I haven't been able
to test those changes.

10 files changed, 50 insertions, 52 deletions

diff --git a/crawl-ref/source/libdos.cc b/crawl-ref/source/libdos.cc
index 62e90ae93d..f20d809fd6 100644
--- a/crawl-ref/source/libdos.cc
+++ b/crawl-ref/source/libdos.cc
@@ -57,20 +57,22 @@ static void scroll_message_window()
         cgotoxy(x, y - 1);
 }
 
-void message_out(int which_line, int colour, const char *s, int firstcol,
-                 bool newline)
+void message_out(int *which_line, int colour, const char *s, int firstcol)
 {
     if (!firstcol)
         firstcol = Options.delay_message_clear? 2 : 1;
 
+    while (*which_line > crawl_view.msgsz.y - 1)
+    {
+        scroll_message_window();
+        (*which_line)--;
+    }
+
     cgotoxy(firstcol + crawl_view.msgp.x - 1,
            which_line + crawl_view.msgp.y);
     textcolor(colour);
 
     cprintf("%s", s);
-
-    if (newline && which_line == crawl_view.msgsz.y - 1)
-        scroll_message_window();
 }
 
 void set_cursor_enabled(bool enabled)
diff --git a/crawl-ref/source/libdos.h b/crawl-ref/source/libdos.h
index 6691d499d9..99f326e6de 100644
--- a/crawl-ref/source/libdos.h
+++ b/crawl-ref/source/libdos.h
@@ -28,8 +28,7 @@ void clear_to_end_of_line();
 int getch_ck();
 static inline void set_mouse_enabled(bool enabled) { }
 
-void message_out(int mline, int colour, const char *str, int firstcol = 0,
-                 bool newline = true);
+void message_out(int *mline, int colour, const char *str, int firstcol = 0);
 void clear_message_window();
 inline void update_screen()
 {
diff --git a/crawl-ref/source/libgui.cc b/crawl-ref/source/libgui.cc
index 6eb4339076..568faa0d69 100644
--- a/crawl-ref/source/libgui.cc
+++ b/crawl-ref/source/libgui.cc
@@ -311,9 +311,9 @@ int clrscr()
     return 0;
 }
 
-void message_out(int which_line, int colour, const char *s, int firstcol, bool newline)
+void message_out(int *which_line, int colour, const char *s, int firstcol)
 {
-    tiles.message_out(which_line, colour, s, firstcol, newline);
+    tiles.message_out(*which_line, colour, s, firstcol);
 }
 
 void cgotoxy(int x, int y, int region)
diff --git a/crawl-ref/source/libgui.h b/crawl-ref/source/libgui.h
index 9932520a83..d738075d7e 100644
--- a/crawl-ref/source/libgui.h
+++ b/crawl-ref/source/libgui.h
@@ -57,7 +57,7 @@ int window(int x1, int y1, int x2, int y2);
 extern "C" int getch();
 int getch_ck();
 int clrscr();
-void message_out(int which_line, int colour, const char *s, int firstcol = 0, bool newline = true);
+void message_out(int *which_line, int colour, const char *s, int firstcol = 0);
 void cgotoxy(int x, int y, int region = GOTO_CRT);
 void clear_message_window();
 void delay(int ms);
diff --git a/crawl-ref/source/libunix.cc b/crawl-ref/source/libunix.cc
index f8c462edce..11b7419c85 100644
--- a/crawl-ref/source/libunix.cc
+++ b/crawl-ref/source/libunix.cc
@@ -419,8 +419,7 @@ void clear_message_window()
     wrefresh( Message_Window );
 }
 
-void message_out(int which_line, int color, const char *s, int firstcol,
-                 bool newline)
+void message_out(int *which_line, int color, const char *s, int firstcol)
 {
     (void)wattrset( Message_Window, curs_fg_attr(color) );
 
@@ -429,20 +428,22 @@ void message_out(int which_line, int color, const char *s, int firstcol,
     else
         firstcol--;
 
-    int x, y;
-    getyx(Message_Window, y, x);
-    if (newline && which_line == y && which_line == crawl_view.msgsz.y - 1)
+    while (*which_line >= crawl_view.msgsz.y)
     {
+        int x, y;
+        getyx(Message_Window, y, x);
         scroll(Message_Window);
         wmove(Message_Window, y - 1, x);
+        (*which_line)--;
     }
 
-    wmove(Message_Window, which_line, firstcol);
+    wmove(Message_Window, *which_line, firstcol);
     waddstr_with_altcharset(Message_Window, s);
 
     // Fix stdscr cursor to same place as Message_Window cursor. This
     // is necessary because when reading input we use stdscr.
     {
+        int x, y;
         getyx(Message_Window, y, x);
         move(y + crawl_view.msgp.y - 1, crawl_view.msgp.x - 1 + x);
     }
diff --git a/crawl-ref/source/libunix.h b/crawl-ref/source/libunix.h
index 8da80d559c..3a9df9f6d8 100644
--- a/crawl-ref/source/libunix.h
+++ b/crawl-ref/source/libunix.h
@@ -23,8 +23,7 @@ typedef unsigned short screen_buffer_t;
 
 char getche(void);
 
-void message_out(int mline, int colour, const char *str, int firstcol = 0,
-                 bool newline = true);
+void message_out(int *mline, int colour, const char *str, int firstcol = 0);
 void clear_message_window();
 
 int get_number_of_lines();
diff --git a/crawl-ref/source/libw32c.cc b/crawl-ref/source/libw32c.cc
index 36cc261851..18eb36cbac 100644
--- a/crawl-ref/source/libw32c.cc
+++ b/crawl-ref/source/libw32c.cc
@@ -617,20 +617,23 @@ static void scroll_message_window()
         cgotoxy(wherex(), wherey() - 1);
 }
 
-void message_out(int which_line, int colour, const char *s, int firstcol,
-                 bool newline)
+void message_out(int *which_line, int colour, const char *s, int firstcol)
 {
     if (!firstcol)
         firstcol = Options.delay_message_clear? 2 : 1;
 
+    while (*which_line > crawl_view.msgsz.y - 1)
+    {
+        scroll_message_window();
+        (*which_line)--;
+    }
+
     cgotoxy(firstcol - 1 + crawl_view.msgp.x,
            which_line + crawl_view.msgp.y);
     textcolor(colour);
 
     cprintf("%s", s);
 
-    if (newline && which_line == crawl_view.msgsz.y - 1)
-        scroll_message_window();
 }
 
 static void cprintf_aux(const char *s)
diff --git a/crawl-ref/source/libw32c.h b/crawl-ref/source/libw32c.h
index 58689abb15..c7eed44478 100644
--- a/crawl-ref/source/libw32c.h
+++ b/crawl-ref/source/libw32c.h
@@ -12,8 +12,7 @@ typedef unsigned short screen_buffer_t;
 void init_libw32c(void);
 void deinit_libw32c(void);
 
-void message_out(int mline, int colour, const char *str, int firstcol = 0,
-                 bool newline = true);
+void message_out(int *mline, int colour, const char *str, int firstcol = 0);
 void clear_message_window();
 
 int get_number_of_lines();
diff --git a/crawl-ref/source/message.cc b/crawl-ref/source/message.cc
index 093fdb4df0..561247b7ea 100644
--- a/crawl-ref/source/message.cc
+++ b/crawl-ref/source/message.cc
@@ -676,8 +676,6 @@ static void mpr_store_messages(const std::string& message,
                                msg_channel_type channel, int param,
                                unsigned char colour, int repeats = 1)
 {
-    const int num_lines = crawl_view.msgsz.y;
-
     bool was_repeat = false;
 
     if (Options.msg_condense_repeats)
@@ -704,8 +702,7 @@ static void mpr_store_messages(const std::string& message,
     if (channel != MSGCH_PROMPT)
         New_Message_Count++;
 
-    if (Message_Line < num_lines - 1)
-        Message_Line++;
+    Message_Line++;
 
     // Reset colour.
     textcolor(LIGHTGREY);
@@ -726,8 +723,6 @@ static void mpr_store_messages(const std::string& message,
     }
 }
 
-static bool did_prefix = false;
-
 // Does the work common to base_mpr and formatted_mpr.
 // Returns the default colour of the message, or MSGCOL_MUTED if
 // the message should be suppressed.
@@ -840,9 +835,8 @@ static void base_mpr(const char *inf, msg_channel_type channel, int param,
         snprintf(info, INFO_SIZE, "%s (x%d)", inf, repeats);
         inf = info;
     }
-    message_out(Message_Line, colour, inf,
-                Options.delay_message_clear ? 2 : 1, !did_prefix);
-    did_prefix = false;
+    message_out(&Message_Line, colour, inf,
+                Options.delay_message_clear ? 2 : 1);
 
     if (channel == MSGCH_PROMPT || channel == MSGCH_ERROR)
         set_more_autoclear(false);
@@ -885,15 +879,13 @@ static void mpr_formatted_output(formatted_string fs, int colour)
             colour = fs.ops[i].x;
             break;
         case FSOP_TEXT:
-            message_out(Message_Line, colour, fs.ops[i].text.c_str(), curcol,
-                        (i == last_text) && !did_prefix);
+            message_out(&Message_Line, colour, fs.ops[i].text.c_str(), curcol);
             curcol += multibyte_strlen(fs.ops[i].text);
             break;
         case FSOP_CURSOR:
             break;
         }
     }
-    did_prefix = false;
 }
 
 // Line wrapping is not available here!
@@ -993,7 +985,7 @@ bool any_messages(void)
     return (Message_Line > 0);
 }
 
-void mesclr( bool force )
+void mesclr(bool force)
 {
     if (crawl_state.game_crashed)
         return;
@@ -1009,9 +1001,7 @@ void mesclr( bool force )
 
     if (!force && Options.delay_message_clear)
     {
-        if (!did_prefix)
-            message_out( Message_Line, WHITE, "-", 1, true);
-        did_prefix = true;
+        message_out(&Message_Line, WHITE, "-", 1);
         return;
     }
 
@@ -1019,7 +1009,6 @@ void mesclr( bool force )
 
     cursor_control cs(false);
     clear_message_window();
-    did_prefix = false;
     Message_Line = 0;
 }
 
@@ -1070,19 +1059,22 @@ void more(bool user_forced)
 
         int keypress = 0;
 
+        int line = crawl_view.msgsz.y - 1;
+
+        // Force scroll.
+        if (Options.delay_message_clear)
+            line++;
+
         if (Tutorial.tutorial_left)
         {
-            message_out(crawl_view.msgsz.y - 1,
-                        LIGHTGREY,
+            message_out(&line, LIGHTGREY,
                         "--more--                        "
                         "Press Ctrl-P to reread old messages.",
-                        2, Options.delay_message_clear);
+                        2);
         }
         else
         {
-            message_out(crawl_view.msgsz.y - 1,
-                        LIGHTGREY, "--more--", 2,
-                        Options.delay_message_clear);
+            message_out(&line, LIGHTGREY, "--more--", 2);
         }
 
         mouse_control mc(MOUSE_MODE_MORE);
diff --git a/crawl-ref/source/tilesdl.cc b/crawl-ref/source/tilesdl.cc
index 51ed39ea10..de5782ff75 100644
--- a/crawl-ref/source/tilesdl.cc
+++ b/crawl-ref/source/tilesdl.cc
@@ -1207,19 +1207,22 @@ void TilesFramework::clrscr()
     cgotoxy(1,1);
 }
 
-void TilesFramework::message_out(int which_line, int colour, const char *s,
-                                 int firstcol, bool newline)
+void TilesFramework::message_out(int *which_line, int colour, const char *s,
+                                 int firstcol)
 {
     if (!firstcol)
         firstcol = Options.delay_message_clear ? 2 : 1;
 
+    while (*which_line > crawl_view.msgsz.y - 1)
+    {
+        m_region_msg->scroll();
+        (*which_line)--;
+    }
+
     cgotoxy(firstcol, which_line + 1, GOTO_MSG);
     textcolor(colour);
 
     cprintf("%s", s);
-
-    if (newline && which_line == crawl_view.msgsz.y - 1)
-        m_region_msg->scroll();
 }
 
 void TilesFramework::clear_message_window()