From 8f94b3295337eb929cddcf6551a675c654e6f9aa Mon Sep 17 00:00:00 2001
From: Nathan Vegdahl <cessen@cessen.com>
Date: Sat, 7 Feb 2015 22:57:25 -0800
Subject: [PATCH] Have view scrolling nearly working again.

Just doesn't *quite* work with wrapped lines.  Need to investigate.
---
 src/editor/mod.rs | 19 +++++++++++++------
 src/formatter.rs  |  7 ++++++-
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/editor/mod.rs b/src/editor/mod.rs
index 420a7d2..a7689f0 100644
--- a/src/editor/mod.rs
+++ b/src/editor/mod.rs
@@ -296,17 +296,24 @@ impl<T: LineFormatter> Editor<T> {
     
     /// Moves the editor's view the minimum amount to show the cursor
     pub fn move_view_to_cursor(&mut self) {
+        // TODO: account for the horizontal offset of the editor view.
+
         // TODO: handle multiple cursors properly.  Should only move if
         // there are no cursors currently in view, and should jump to
         // the closest cursor.
         
-        //let gi = self.cursors[0].range.0;
-        //let vho = self.cursors[0].vis_start;
-        
-        //self.view_pos.0 = gi;
+        // Find the first and last grapheme index visible within the editor.
+        let g_first = self.formatter.index_set_horizontal_v2d(&self.buffer, self.view_pos.0, 0, Floor);
+        let mut g_last = self.formatter.index_offset_vertical_v2d(&self.buffer, g_first, (self.view_dim.0 - 1) as isize, (Floor, Floor));
+        g_last = self.formatter.index_set_horizontal_v2d(&self.buffer, g_last, self.view_dim.1, Floor);
 
-        // TODO: horizontal offset
-        //self.view_pos.1 = vho;
+        // Adjust the view depending on where the cursor is        
+        if self.cursors[0].range.0 < g_first {
+            self.view_pos.0 = self.cursors[0].range.0;
+        }
+        else if self.cursors[0].range.0 > g_last {
+            self.view_pos.0 = self.formatter.index_offset_vertical_v2d(&self.buffer, self.cursors[0].range.0, -((self.view_dim.0 - 1) as isize), (Floor, Floor));
+        }
     }
     
     
diff --git a/src/formatter.rs b/src/formatter.rs
index 3f1a90c..1b4e637 100644
--- a/src/formatter.rs
+++ b/src/formatter.rs
@@ -94,7 +94,12 @@ pub trait LineFormatter {
         
         let (v, _) = self.index_to_v2d(line, col_i);
         let mut new_col_i = self.v2d_to_index(line, (v, horizontal), (RoundingBehavior::Floor, rounding));
-        if new_col_i >= line.grapheme_count() && line.grapheme_count() > 0 {
+        
+        // Make sure we're not pushing the index off the end of the line
+        if (line_i + 1) < buf.line_count()
+        && new_col_i >= line.grapheme_count()
+        && line.grapheme_count() > 0
+        {
             new_col_i = line.grapheme_count() - 1;
         }