insert and delete line functions utilizing csr.

lib/program.js

@@ -2031,6 +2031,7 @@ Program.prototype.setMouse = function(opt) {
 //   dow) (DECSTBM).
 // CSI ? Pm r
 Program.prototype.decstbm =
+Program.prototype.csr =
 Program.prototype.setScrollRegion = function(top, bottom) {
   this.scrollTop = (top || 1) - 1;
   this.scrollBottom = (bottom || this.rows) - 1;

lib/widget.js

@@ -270,6 +270,66 @@ Screen.prototype.render = function() {
   this.emit('draw');
 };
 
+Screen.prototype.blankLine = function(ch, dirty) {
+  var out = [];
+  for (var y = 0; y < this.rows; y++) {
+    out[y] = [];
+    for (var x = 0; x < this.cols; x++) {
+      out[y][x] = [this.dattr, ch || ' '];
+    }
+    out[y].dirty = dirty;
+  }
+  return out;
+};
+
+Screen.prototype.insertLine = function(n, y, top, bottom) {
+  this.program.csr(top + 1, bottom + 1);
+  this.program.cup(y + 1, 1);
+  this.program.il(1);
+  this.program.csr(1, this.height - 1 + 1);
+  this.program.cup(y + 1, 1);
+
+  if (n < 1) n = 1;
+
+  var j = this.rows - 1 - bottom;
+  j = this.rows - 1 - j + 1;
+
+  while (n--) {
+    this.lines.splice(y, 0, this.blankLine());
+    this.lines.splice(j, 1);
+    this.olines.splice(y, 0, this.blankLine());
+    this.olines.splice(j, 1);
+  }
+};
+
+Screen.prototype.deleteLine = function(n, y, top, bottom) {
+  this.program.csr(top + 1, bottom + 1);
+  this.program.cup(y + 1, 1);
+  this.program.dl(1);
+  this.program.csr(1, this.height - 1 + 1);
+  this.program.cup(y + 1, 1);
+
+  if (n < 1) n = 1;
+
+  var j = this.rows - 1 - bottom;
+  j = this.rows - 1 - j + 1;
+
+  while (n--) {
+    this.lines.splice(j, 0, this.blankLine());
+    this.lines.splice(y, 1);
+    this.olines.splice(j, 0, this.blankLine());
+    this.olines.splice(y, 1);
+  }
+};
+
+Screen.prototype.insertBottom = function(top, bottom) {
+  return this.deleteLine(1, top, top, bottom);
+};
+
+Screen.prototype.insertTop = function(top, bottom) {
+  return this.insertLine(1, top, top, bottom);
+};
+
 Screen.prototype.draw = function(start, end) {
   var x
     , y