add getScroll method.

lib/widget.js

@@ -3108,7 +3108,7 @@ Element.prototype.render = function() {
     if (this.alwaysScroll) {
       y = this.childBase / (i - (yl - yi));
     } else {
-      y = (this.childBase + this.childOffset) / i;
+      y = (this.childBase + this.childOffset) / (i - 1);
     }
     y = yi + ((yl - yi) * y | 0);
     if (y >= yl) y = yl - 1;
@@ -3635,10 +3635,15 @@ ScrollableBox.prototype._scrollBottom = function() {
   return bottom;
 };
 
+ScrollableBox.prototype.setScroll =
 ScrollableBox.prototype.scrollTo = function(offset) {
   return this.scroll(offset - (this.childBase + this.childOffset));
 };
 
+ScrollableBox.prototype.getScroll = function() {
+  return this.childBase + this.childOffset;
+};
+
 ScrollableBox.prototype.scroll = function(offset, always) {
   if (!this.scrollable) return;
 
@@ -3755,6 +3760,31 @@ ScrollableBox.prototype.resetScroll = function() {
   return this.emit('scroll');
 };
 
+ScrollableBox.prototype.getScrollPerc = function(s) {
+  var pos = this.lpos || this._getCoords();
+  if (!pos) return s ? -1 : 0;
+
+  var height = (pos.yl - pos.yi) - this.iheight
+    , i = Math.max(this._clines.length, this._scrollBottom())
+    , p;
+
+  if (height < i) {
+    if (this.alwaysScroll) {
+      p = this.childBase / (i - height);
+    } else {
+      p = (this.childBase + this.childOffset) / (i - 1);
+    }
+    return p * 100;
+  }
+
+  return s ? -1 : 0;
+};
+
+ScrollableBox.prototype.setScrollPerc = function(i) {
+  var m = Math.max(this._clines.length, this._scrollBottom());
+  return this.scrollTo((i / 100) * m | 0);
+};
+
 /**
  * ScrollableText
  */