[PATCH v2] gitk: Synchronize highlighting in file view when scrolling diff

[Stefan Haller <stefan@haller-berlin.de>]

Whenever the diff pane scrolls, highlight the corresponding file in the
file list on the right. For a large commit with many files and long
per-file diffs, this makes it easier to keep track of what you're looking
at.

This allows simplifying the prevfile and nextfile functions, because
all they have to do is scroll the diff pane.

Signed-off-by: Stefan Haller <stefan@haller-berlin.de>
---
The only change from v1 is the addition of the "$difffilestart eq {}" 
condition, this should fix the flickering problem reported by Peter.
I didn't do anything about the search problem yet, will look into this
next. (Personally though, I think this is acceptable the way it is.)

 gitk | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/gitk b/gitk
index d93bd99..8095806 100755
--- a/gitk
+++ b/gitk
@@ -7947,10 +7947,9 @@ proc changediffdisp {} {
     $ctext tag conf dresult -elide [lindex $diffelide 1]
 }
 
-proc highlightfile {loc cline} {
-    global ctext cflist cflist_top
+proc highlightfile {cline} {
+    global cflist cflist_top
 
-    $ctext yview $loc
     $cflist tag remove highlight $cflist_top.0 "$cflist_top.0 lineend"
     $cflist tag add highlight $cline.0 "$cline.0 lineend"
     $cflist see $cline.0
@@ -7962,17 +7961,15 @@ proc prevfile {} {
 
     if {$cmitmode eq "tree"} return
     set prev 0.0
-    set prevline 1
     set here [$ctext index @0,0]
     foreach loc $difffilestart {
 	if {[$ctext compare $loc >= $here]} {
-	    highlightfile $prev $prevline
+	    $ctext yview $prev
 	    return
 	}
 	set prev $loc
-	incr prevline
     }
-    highlightfile $prev $prevline
+    $ctext yview $prev
 }
 
 proc nextfile {} {
@@ -7980,11 +7977,9 @@ proc nextfile {} {
 
     if {$cmitmode eq "tree"} return
     set here [$ctext index @0,0]
-    set line 1
     foreach loc $difffilestart {
-	incr line
 	if {[$ctext compare $loc > $here]} {
-	    highlightfile $loc $line
+	    $ctext yview $loc
 	    return
 	}
     }
@@ -8138,7 +8133,17 @@ proc searchmarkvisible {doall} {
 }
 
 proc scrolltext {f0 f1} {
-    global searchstring
+    global searchstring cmitmode
+    global ctext cflist cflist_top difffilestart
+
+    if {$cmitmode ne "tree" && [info exists difffilestart]} {
+	set top [lindex [split [$ctext index @0,0] .] 0]
+	if {$difffilestart eq {} || $top < [lindex $difffilestart 0]} {
+	    highlightfile 0
+	} else {
+	    highlightfile [expr {[bsearch $difffilestart $top] + 2}]
+	}
+    }
 
     .bleft.bottom.sb set $f0 $f1
     if {$searchstring ne {}} {
-- 
1.7.12.517.g4c1112f