fix error caused when screen.render() is called during a delayed resize.

lib/widget.js

@@ -660,7 +660,11 @@ Screen.prototype.render = function() {
   });
   this._ci = -1;
 
-  this.draw(0, this.rows - 1);
+  // Cannot use this.rows here because of the resize delay:
+  // `rows` and `cols` get set instantly by the resize, but `alloc` has a 300ms
+  // delay before the new cells are added, which will sometimes throw. Measure
+  // by lines.
+  this.draw(0, this.lines.length - 1);
 
   // XXX Workaround to deal with cursor pos before the screen has rendered and
   // lpos is not reliable (stale).
@@ -908,7 +912,11 @@ Screen.prototype.draw = function(start, end) {
     out = '';
     attr = this.dattr;
 
-    for (x = 0; x < this.cols; x++) {
+    // Cannot use this.cols here because of the resize delay:
+    // `rows` and `cols` get set instantly by the resize, but `alloc` has a
+    // 300ms delay before the new cells are added, which will sometimes throw.
+    // Measure by line length.
+    for (x = 0; x < line.length; x++) {
       data = line[x][0];
       ch = line[x][1];