* Fixed \ESC[0J (erase screen below). It shall not erase any character

on the line before the cursor.
* Implemented \ESC[1J (erase screen above.
* Fixed \ESC[2J (erase all). It shall not move the cursor.
* When scrolling only the top part of the screen, we do now also
  invalidate the line below the scroll region. Otherwise the view
  wouldn't know that they have not been scrolled.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25986 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/apps/terminal/BasicTerminalBuffer.cpp

@@ -628,10 +628,39 @@ BasicTerminalBuffer::InsertSpace(int32 num)
 }
 
 
+void
+BasicTerminalBuffer::EraseAbove()
+{
+	// Clear the preceding lines.
+	if (fCursor.y > 0)
+		_ClearLines(0, fCursor.y - 1);
+
+	// Delete the chars on the cursor line before (and including) the cursor.
+	TerminalLine* line = _LineAt(fCursor.y);
+	if (fCursor.x < line->length) {
+		int32 to = fCursor.x;
+		if (IS_WIDTH(line->cells[fCursor.x].attributes))
+			to++;
+		for (int32 i = 0; i <= to; i++) {
+			line->cells[i].attributes = 0;
+			line->cells[i].character = kSpaceChar;
+		}
+	} else
+		line->Clear();
+
+	_Invalidate(fCursor.y, fCursor.y);
+}
+
+
 void
 BasicTerminalBuffer::EraseBelow()
 {
-	_Scroll(fCursor.y, fHeight - 1, fHeight);
+	// Clear the following lines.
+	if (fCursor.y < fHeight - 1)
+		_ClearLines(fCursor.y + 1, fHeight - 1);
+
+	// Delete the chars on the cursor line after (and including) the cursor.
+	DeleteColumns();
 }
 
 
@@ -1146,6 +1175,14 @@ BasicTerminalBuffer::_Scroll(int32 top, int32 bottom, int32 numLines)
 
 			// invalidate new empty lines
 			_Invalidate(bottom + 1 - numLines, bottom);
+
+			// In case only part of the screen was scrolled, we invalidate also
+			// the lines below the scroll region. Those remain unchanged, but
+			// we can't convey that they have not been scrolled via
+			// TerminalBufferDirtyInfo. So we need to force the view to sync
+			// them again.
+			if (bottom < fHeight - 1)
+				_Invalidate(bottom + 1, fHeight - 1);
 		} else if (numLines >= bottom - top + 1) {
 			// all lines are completely scrolled out of range -- just clear
 			// them

src/apps/terminal/BasicTerminalBuffer.h

@@ -104,6 +104,7 @@ public:
 			void				InsertLines(int32 numLines);
 	
 			// delete chars/lines
+			void				EraseAbove();
 			void				EraseBelow();
 			void				DeleteChars(int32 numChars);
 			void				DeleteColumns();

src/apps/terminal/TermParse.cpp

@@ -630,11 +630,12 @@ TermParse::EscParse()
 						break;
 
 					case 1:
+						fBuffer->EraseAbove();
 						break;
 
 					case 2:
-						fBuffer->SetCursor(0, 0);
 						fBuffer->EraseBelow();
+						fBuffer->EraseAbove();
 						break;
 				}
 				parsestate = groundtable;