[PATCH] gitk: Add horizontal scrollbar to the diff view

Adding horizontal scroll bar makes the scrolling feature more
discoverable to the users.  The horizontal scrollbar is a bit narrower
than vertical ones so we don't make too big impact on available screen
real estate.  The text and scrollbar widget layout is done using grid
geometry manager.

An interesting side effect of Tk scrollbars is that the "elevator"
size changes depending on the visible content. So the horizontal
scrollbar "elevator" changes as the user scrolls the view up and down.

Signed-off-by: Pekka Kaitaniemi <kaitanie@cc.helsinki.fi>
Signed-off-by: Paul Mackerras <paulus@samba.org>

gitk

@@ -837,6 +837,7 @@ proc makewindow {} {
     }
     frame .bleft.top
     frame .bleft.mid
+    frame .bleft.bottom
 
     button .bleft.top.search -text [mc "Search"] -command dosearch
     pack .bleft.top.search -side left -padx 5
@@ -864,18 +865,25 @@ proc makewindow {} {
     checkbutton .bleft.mid.ignspace -text [mc "Ignore space change"] \
 	-command changeignorespace -variable ignorespace
     pack .bleft.mid.ignspace -side left -padx 5
-    set ctext .bleft.ctext
+    set ctext .bleft.bottom.ctext
     text $ctext -background $bgcolor -foreground $fgcolor \
 	-state disabled -font textfont \
-	-yscrollcommand scrolltext -wrap none
+	-yscrollcommand scrolltext -wrap none \
+	-xscrollcommand ".bleft.bottom.sbhorizontal set"
     if {$have_tk85} {
 	$ctext conf -tabstyle wordprocessor
     }
-    scrollbar .bleft.sb -command "$ctext yview"
+    scrollbar .bleft.bottom.sb -command "$ctext yview"
+    scrollbar .bleft.bottom.sbhorizontal -command "$ctext xview" -orient h \
+	-width 10
     pack .bleft.top -side top -fill x
     pack .bleft.mid -side top -fill x
-    pack .bleft.sb -side right -fill y
-    pack $ctext -side left -fill both -expand 1
+    grid $ctext .bleft.bottom.sb -sticky nsew
+    grid .bleft.bottom.sbhorizontal -sticky ew
+    grid columnconfigure .bleft.bottom 0 -weight 1
+    grid rowconfigure .bleft.bottom 0 -weight 1
+    grid rowconfigure .bleft.bottom 1 -weight 0
+    pack .bleft.bottom -side top -fill both -expand 1
     lappend bglist $ctext
     lappend fglist $ctext
 
@@ -5640,7 +5648,7 @@ proc searchmarkvisible {doall} {
 proc scrolltext {f0 f1} {
     global searchstring
 
-    .bleft.sb set $f0 $f1
+    .bleft.bottom.sb set $f0 $f1
     if {$searchstring ne {}} {
 	searchmarkvisible 0
     }