Merge pull request #1507 from ajaxorg/scroll_past_end

[WIP] scrollPastEnd

demo/kitchen-sink/demo.js

@@ -430,6 +430,9 @@ bindCheckbox("fade_fold_widgets", function(checked) {
 bindCheckbox("read_only", function(checked) {
     env.editor.setReadOnly(checked);
 });
+bindCheckbox("scrollPastEnd", function(checked) {
+    env.editor.setOption("scrollPastEnd", checked);
+});
 
 bindDropdown("split", function(value) {
     var sp = env.split;

kitchen-sink.html

@@ -274,6 +274,14 @@
         <input type="checkbox" id="read_only">
       </td>
     </tr>
+    <tr>
+      <td >
+        <label for="scrollPastEnd">Scroll Past End</label>
+      </td>
+      <td>
+        <input type="checkbox" id="scrollPastEnd" checked>
+      </td>
+    </tr>
     <tr>
       <td colspan="2">
         <input type="button" value="Edit Snippets" onclick="env.editSnippets()">

lib/ace/editor.js

@@ -2261,6 +2261,7 @@ config.defineOptions(Editor.prototype, "editor", {
     fontFamily: "renderer",
     maxLines: "renderer",
     minLines: "renderer",
+    scrollPastEnd: "renderer",
 
     scrollSpeed: "$mouseHandler",
     dragDelay: "$mouseHandler",

lib/ace/virtual_renderer.js

@@ -848,7 +848,7 @@ var VirtualRenderer = function(container, theme) {
         
         var hideScrollbars = this.$size.height <= 2 * this.lineHeight;
         var screenLines = this.session.getScreenLength()
-        var maxHeight =  screenLines * this.lineHeight;
+        var maxHeight = screenLines * this.lineHeight;
 
         var offset = this.scrollTop % this.lineHeight;
         var minHeight = this.$size.scrollerHeight + this.lineHeight;
@@ -864,6 +864,14 @@ var VirtualRenderer = function(container, theme) {
             this.scrollBarH.setVisible(horizScroll);
         }
         
+        if (!this.$maxLines && this.$scrollPastEnd) {
+            if (this.scrollTop > maxHeight - this.$size.scrollerHeight)
+                maxHeight += Math.min(
+                    (this.$size.scrollerHeight - this.lineHeight) * this.$scrollPastEnd,
+                    this.scrollTop - maxHeight + this.$size.scrollerHeight
+                );
+        }
+        
         var vScroll = !hideScrollbars && (this.$vScrollBarAlwaysVisible ||
             this.$size.scrollerHeight - maxHeight < 0);
         var vScrollChanged = this.$vScroll !== vScroll;
@@ -1268,7 +1276,8 @@ var VirtualRenderer = function(container, theme) {
         if (deltaY < 0 && this.session.getScrollTop() >= 1 - this.scrollMargin.top)
            return true;
         if (deltaY > 0 && this.session.getScrollTop() + this.$size.scrollerHeight
-            - this.layerConfig.maxHeight < -1 + this.scrollMargin.bottom)
+            - this.layerConfig.maxHeight - (this.$size.scrollerHeight - this.lineHeight) * this.$scrollPastEnd
+            < -1 + this.scrollMargin.bottom)
            return true;
         // todo: better handle horizontal scrolling
         if (deltaX)
@@ -1579,9 +1588,23 @@ config.defineOptions(VirtualRenderer.prototype, "renderer", {
         }
     },
     minLines: {
-        set: function(name) {        
+        set: function(val) {
             this.updateFull();
         }
+    },
+    scrollPastEnd: {
+        set: function(val) {
+            if (val == true)
+                val = 1;
+            else if (val == false)
+                val = 0;
+            if (this.$scrollPastEnd == val)
+                return;
+            this.$scrollPastEnd = val;
+            this.$loop.schedule(this.CHANGE_SCROLL);
+        },
+        initialValue: 1,
+        handlesSet: true
     }
 });