Implement scrolling region

terminal.cpp

@@ -88,7 +88,8 @@ void Emulator::print( Parser::Print *act )
       fb.ds.move_col( 1, true, true );
     }
 
-    if ( combining_cell->contents.size() < 16 ) { /* seems like a reasonable limit on combining characters */
+    if ( combining_cell->contents.size() < 16 ) {
+      /* seems like a reasonable limit on combining characters */
       combining_cell->contents.push_back( act->ch );
     }
     act->handled = true;

terminalframebuffer.cpp

@@ -57,6 +57,7 @@ DrawState::DrawState( int s_width, int s_height )
   : width( s_width ), height( s_height ),
     cursor_col( 0 ), cursor_row( 0 ),
     combining_char_col( 0 ), combining_char_row( 0 ), tabs( s_width ),
+    scrolling_region_top_row( 0 ), scrolling_region_bottom_row( height - 1 ),
     next_print_will_wrap( false ), origin_mode( false ), auto_wrap_mode( true )
 {
   for ( int i = 0; i < width; i++ ) {
@@ -72,16 +73,16 @@ void Framebuffer::scroll( int N )
 {
   if ( N >= 0 ) {
     for ( int i = 0; i < N; i++ ) {
-      rows.pop_front();
-      rows.push_back( Row( ds.get_width() ) );
+      rows.erase( rows.begin() + ds.limit_top() );
+      rows.insert( rows.begin() + ds.limit_bottom(), Row( ds.get_width() ) );
       ds.move_row( -1, true );
     }
   } else {
     N = -N;
 
     for ( int i = 0; i < N; i++ ) {
-      rows.pop_back();
-      rows.push_front( Row( ds.get_width() ) );
+      rows.erase( rows.begin() + ds.limit_bottom() );
+      rows.insert( rows.begin() + ds.limit_top(), Row( ds.get_width() ) );
       ds.move_row( 1, true );
     }
   }
@@ -95,8 +96,8 @@ void DrawState::new_grapheme( void )
 
 void DrawState::snap_cursor_to_border( void )
 {
-  if ( cursor_row < 0 ) cursor_row = 0;
-  if ( cursor_row >= height ) cursor_row = height - 1;
+  if ( cursor_row < limit_top() ) cursor_row = limit_top();
+  if ( cursor_row > limit_bottom() ) cursor_row = limit_bottom();
   if ( cursor_col < 0 ) cursor_col = 0;
   if ( cursor_col >= width ) cursor_col = width - 1;
 }
@@ -139,10 +140,10 @@ void DrawState::move_col( int N, bool relative, bool implicit )
 
 void Framebuffer::move_rows_autoscroll( int rows )
 {
-  if ( ds.get_cursor_row() + rows >= ds.get_height() ) {
-    scroll( ds.get_height() - ds.get_cursor_row() - rows + 1 );
-  } else if ( ds.get_cursor_row() + rows < 0 ) {
-    scroll( ds.get_cursor_row() + rows );
+  if ( ds.get_cursor_row() + rows > ds.limit_bottom() ) {
+    scroll( ds.get_cursor_row() + rows - ds.limit_bottom() );
+  } else if ( ds.get_cursor_row() + rows < ds.limit_top() ) {
+    scroll( ds.get_cursor_row() + rows - ds.limit_top() );
   }
 
   ds.move_row( rows, true );
@@ -203,3 +204,35 @@ int DrawState::get_next_tab( void )
   }
   return -1;
 }
+
+void DrawState::set_scrolling_region( int top, int bottom )
+{
+  if ( height < 1 ) {
+    return;
+  }
+
+  scrolling_region_top_row = top;
+  scrolling_region_bottom_row = bottom;
+
+  if ( scrolling_region_top_row < 0 ) scrolling_region_top_row = 0;
+  if ( scrolling_region_bottom_row >= height ) scrolling_region_bottom_row = height - 1;
+
+  if ( scrolling_region_bottom_row < scrolling_region_top_row )
+    scrolling_region_bottom_row = scrolling_region_top_row;
+  /* real rule requires TWO-line scrolling region */
+
+  if ( origin_mode ) {
+    snap_cursor_to_border();
+    new_grapheme();
+  }
+}
+
+int DrawState::limit_top( void )
+{
+  return origin_mode ? scrolling_region_top_row : 0;
+}
+
+int DrawState::limit_bottom( void )
+{
+  return origin_mode ? scrolling_region_bottom_row : height - 1;
+}

terminalframebuffer.hpp

@@ -42,6 +42,8 @@ namespace Terminal {
 
     std::vector<bool> tabs;
 
+    int scrolling_region_top_row, scrolling_region_bottom_row;
+
   public:
     bool next_print_will_wrap;
     bool origin_mode;
@@ -63,6 +65,11 @@ namespace Terminal {
     void clear_tab( int col );
     int get_next_tab( void );
 
+    void set_scrolling_region( int top, int bottom );
+
+    int limit_top( void );
+    int limit_bottom( void );
+
     DrawState( int s_width, int s_height );
   };
 

terminalfunctions.cpp

@@ -177,8 +177,12 @@ static Function func_CSI_TBC( CSI, "g", CSI_TBC );
 static bool *get_DEC_mode( int param, Framebuffer *fb ) {
   switch ( param ) {
   case 3: /* 80/132 */
+    /* clear screen */
     fb->ds.move_row( 0 );
     fb->ds.move_col( 0 );
+    for ( int y = 0; y < fb->ds.get_height(); y++ ) {
+      clearline( fb, y, 0, fb->ds.get_width() - 1 );
+    }
     return NULL;
   case 6: /* origin */
     fb->ds.move_row( 0 );
@@ -212,3 +216,19 @@ void CSI_DECRM( Framebuffer *fb, Dispatcher *dispatch )
 
 static Function func_CSI_DECSM( CSI, "?h", CSI_DECSM );
 static Function func_CSI_DECRM( CSI, "?l", CSI_DECRM );
+
+void CSI_DECSTBM( Framebuffer *fb, Dispatcher *dispatch )
+{
+  int top = dispatch->getparam( 0, 1 );
+  int bottom = dispatch->getparam( 1, fb->ds.get_height() );
+
+  fb->ds.set_scrolling_region( top - 1, bottom - 1 );
+}
+
+static Function func_CSI_DECSTMB( CSI, "r", CSI_DECSTBM );
+
+void Ctrl_BEL( Framebuffer *fb __attribute((unused)), Dispatcher *dispatch __attribute((unused)) )
+{}
+
+static Function func_Ctrl_BEL( CONTROL, "\x07", Ctrl_BEL );
+