From 66562856c8c7e60815da4fb166133d3c77dce9fc Mon Sep 17 00:00:00 2001
From: Joe Cheng <joe@rstudio.org>
Date: Tue, 15 Feb 2011 11:35:47 +0800
Subject: [PATCH] Fix PageUp/PageDown commands, which were badly broken on
 soft-wrapped documents

---
 lib/ace/editor.js           | 56 +++++++++++++++++++------------------
 lib/ace/selection.js        |  9 ++++++
 lib/ace/virtual_renderer.js |  4 +++
 3 files changed, 42 insertions(+), 27 deletions(-)

diff --git a/lib/ace/editor.js b/lib/ace/editor.js
index 60a14c1b..0e16b53a 100644
--- a/lib/ace/editor.js
+++ b/lib/ace/editor.js
@@ -805,68 +805,66 @@ var Editor =function(renderer, session) {
         return (row >= this.getFirstVisibleRow() && row <= this.getLastVisibleRow());
     };
 
-    this.getVisibleRowCount = function() {
-        return this.getLastVisibleRow() - this.getFirstVisibleRow() + 1;
+    this.$getVisibleRowCount = function() {
+        return this.renderer.getScrollBottomRow() - this.renderer.getScrollTopRow() + 1;
     };
 
-    this.getPageDownRow = function() {
-        return this.renderer.getLastVisibleRow() - 1;
+    this.$getPageDownRow = function() {
+        return this.renderer.getScrollBottomRow();
     };
 
-    this.getPageUpRow = function() {
-        var firstRow = this.renderer.getFirstVisibleRow();
-        var lastRow = this.renderer.getLastVisibleRow();
+    this.$getPageUpRow = function() {
+        var firstRow = this.renderer.getScrollTopRow();
+        var lastRow = this.renderer.getScrollBottomRow();
 
-        return firstRow - (lastRow - firstRow) + 1;
+        return firstRow - (lastRow - firstRow);
     };
 
     this.selectPageDown = function() {
-        var row = this.getPageDownRow() + Math.floor(this.getVisibleRowCount() / 2);
+        var row = this.$getPageDownRow() + Math.floor(this.$getVisibleRowCount() / 2);
 
         this.scrollPageDown();
 
         var selection = this.getSelection();
-        selection.$moveSelection(function() {
-            selection.moveCursorTo(row, selection.getSelectionLead().column);
-        });
+        var leadScreenPos = this.session.documentToScreenPosition(selection.getSelectionLead());
+        var dest = this.session.screenToDocumentPosition(row, leadScreenPos.column);
+        selection.selectTo(dest.row, dest.column);
     };
 
     this.selectPageUp = function() {
-        var visibleRows = this.getLastVisibleRow() - this.getFirstVisibleRow();
-        var row = this.getPageUpRow() + Math.round(visibleRows / 2);
+        var visibleRows = this.renderer.getScrollTopRow() - this.renderer.getScrollBottomRow();
+        var row = this.$getPageUpRow() + Math.round(visibleRows / 2);
 
         this.scrollPageUp();
 
         var selection = this.getSelection();
-        selection.$moveSelection(function() {
-            selection.moveCursorTo(row, selection.getSelectionLead().column);
-        });
+        var leadScreenPos = this.session.documentToScreenPosition(selection.getSelectionLead());
+        var dest = this.session.screenToDocumentPosition(row, leadScreenPos.column);
+        selection.selectTo(dest.row, dest.column);
     };
 
     this.gotoPageDown = function() {
-        var row     = this.getPageDownRow(),
-            column  = Math.min(this.getCursorPosition().column,
-                               this.session.getLine(row).length);
+        var row = this.$getPageDownRow();
+        var column = this.getCursorPositionScreen().column;
 
         this.scrollToRow(row);
-        this.getSelection().moveCursorTo(row, column);
+        this.getSelection().moveCursorToScreen(row, column);
     };
 
     this.gotoPageUp = function() {
-       var  row     = this.getPageUpRow(),
-            column  = Math.min(this.getCursorPosition().column,
-                               this.session.getLine(row).length);
+        var row = this.$getPageUpRow();
+        var column = this.getCursorPositionScreen().column;
 
        this.scrollToRow(row);
-       this.getSelection().moveCursorTo(row, column);
+       this.getSelection().moveCursorToScreen(row, column);
     };
 
     this.scrollPageDown = function() {
-        this.scrollToRow(this.getPageDownRow());
+        this.scrollToRow(this.$getPageDownRow());
     };
 
     this.scrollPageUp = function() {
-        this.renderer.scrollToRow(this.getPageUpRow());
+        this.renderer.scrollToRow(this.$getPageUpRow());
     };
 
     this.scrollToRow = function(row) {
@@ -887,6 +885,10 @@ var Editor =function(renderer, session) {
         return this.selection.getCursor();
     };
 
+    this.getCursorPositionScreen = function() {
+        return this.session.documentToScreenPosition(this.getCursorPosition());
+    }
+
     this.getSelectionRange = function() {
         return this.selection.getRange();
     };
diff --git a/lib/ace/selection.js b/lib/ace/selection.js
index a130228d..408f044a 100644
--- a/lib/ace/selection.js
+++ b/lib/ace/selection.js
@@ -408,6 +408,15 @@ var Selection = function(session) {
             this.$updateDesiredColumn(this.selectionLead.column);
     };
 
+    this.moveCursorToScreen = function(row, column, preventUpdateDesiredColumn) {
+        if (this.session.getUseWrapMode()) {
+            var pos = this.session.screenToDocumentPosition(row, column);
+            row = pos.row;
+            column = pos.column;
+        }
+        this.moveCursorTo(row, column, preventUpdateDesiredColumn);
+    };
+
 }).call(Selection.prototype);
 
 exports.Selection = Selection;
diff --git a/lib/ace/virtual_renderer.js b/lib/ace/virtual_renderer.js
index 573aaf58..6be72b88 100644
--- a/lib/ace/virtual_renderer.js
+++ b/lib/ace/virtual_renderer.js
@@ -597,6 +597,10 @@ var VirtualRenderer = function(container, theme) {
         return this.scrollTop / this.lineHeight;
     };
 
+    this.getScrollBottomRow = function() {
+        return Math.max(0, Math.floor((this.scrollTop + this.$size.scrollerHeight) / this.lineHeight) - 1);
+    }
+
     this.scrollToRow = function(row) {
         this.scrollToY(row * this.lineHeight);
     };