From: Paul Mackerras <paulus@samba.org>
Date: Wed, 17 Aug 2005 23:30:10 +0000 (+1000)
Subject: Allow graph lines to jump through hyperspace.
X-Git-Tag: v0.99.5~13^2^2~1
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=f6075ebadb1fce2bd75f2dd68b8aeae40a69158a;p=git.git

Allow graph lines to jump through hyperspace.

When the graph gets too wide (as defined by the maxwidth variable,
which can be set in ~/.gitk), we can now terminate graph lines with
an arrow pointing downwards, and reintroduce them later with an
arrow pointing upwards when we need them.  This makes the graph much
less cluttered on large repositories such as the linux kernel.

Unfortunately this has made it slower; it takes about 10 seconds
user time on the linux-2.6 repository on my machine now, compared
to 6 seconds before.  I'll have to work on optimizing that.  Also
on the todo list are making the arrow heads active (so if you click
on them you jump to the other end) and improving the placement of
the null entry.
---

diff --git a/gitk b/gitk
index c443d9513..f54b4c460 100755
--- a/gitk
+++ b/gitk
@@ -59,7 +59,7 @@ proc getcommits {rargs} {
 }
 
 proc getcommitlines {commfd}  {
-    global commits parents cdate children nchildren
+    global commits parents cdate children
     global commitlisted phase commitinfo nextupdate
     global stopped redisplaying leftover
 
@@ -750,21 +750,24 @@ proc assigncolor {id} {
 }
 
 proc initgraph {} {
-    global canvy canvy0 lineno numcommits lthickness nextcolor linespc
-    global mainline sidelines
+    global canvy canvy0 lineno numcommits nextcolor linespc
+    global mainline mainlinearrow sidelines
     global nchildren ncleft
+    global displist nhyperspace
 
     allcanvs delete all
     set nextcolor 0
     set canvy $canvy0
     set lineno -1
     set numcommits 0
-    set lthickness [expr {int($linespc / 9) + 1}]
     catch {unset mainline}
+    catch {unset mainlinearrow}
     catch {unset sidelines}
     foreach id [array names nchildren] {
 	set ncleft($id) $nchildren($id)
     }
+    set displist {}
+    set nhyperspace 0
 }
 
 proc bindline {t id} {
@@ -776,19 +779,21 @@ proc bindline {t id} {
     $canv bind $t <Button-1> "lineclick %x %y $id 1"
 }
 
+# level here is an index in displist
 proc drawcommitline {level} {
-    global parents children nparents nchildren todo
+    global parents children nparents displist
     global canv canv2 canv3 mainfont namefont canvy linespc
     global lineid linehtag linentag linedtag commitinfo
     global colormap numcommits currentparents dupparents
-    global oldlevel oldnlines oldtodo
     global idtags idline idheads
-    global lineno lthickness mainline sidelines
-    global commitlisted rowtextx idpos
+    global lineno lthickness mainline mainlinearrow sidelines
+    global commitlisted rowtextx idpos lastuse displist
+    global oldnlines olddlevel olddisplist
 
     incr numcommits
     incr lineno
-    set id [lindex $todo $level]
+    set id [lindex $displist $level]
+    set lastuse($id) $lineno
     set lineid($lineno) $id
     set idline($id) $lineno
     set ofill [expr {[info exists commitlisted($id)]? "blue": "white"}]
@@ -819,8 +824,12 @@ proc drawcommitline {level} {
 	[list 0 0 0 [expr $y1 + 0.5 * $linespc + 2]]
     if {[info exists mainline($id)]} {
 	lappend mainline($id) $x $y1
+	if {$mainlinearrow($id) ne "none"} {
+	    set mainline($id) [trimdiagstart $mainline($id)]
+	}
 	set t [$canv create line $mainline($id) \
-		   -width $lthickness -fill $colormap($id)]
+		   -width $lthickness -fill $colormap($id) \
+		   -arrow $mainlinearrow($id)]
 	$canv lower $t
 	bindline $t $id
     }
@@ -828,8 +837,9 @@ proc drawcommitline {level} {
 	foreach ls $sidelines($id) {
 	    set coords [lindex $ls 0]
 	    set thick [lindex $ls 1]
+	    set arrow [lindex $ls 2]
 	    set t [$canv create line $coords -fill $colormap($id) \
-		       -width [expr {$thick * $lthickness}]]
+		       -width [expr {$thick * $lthickness}] -arrow $arrow]
 	    $canv lower $t
 	    bindline $t $id
 	}
@@ -840,7 +850,7 @@ proc drawcommitline {level} {
 	       -fill $ofill -outline black -width 1]
     $canv raise $t
     $canv bind $t <1> {selcanvline {} %x %y}
-    set xt [xcoord [llength $todo] $level $lineno]
+    set xt [xcoord [llength $displist] $level $lineno]
     if {[llength $currentparents] > 2} {
 	set xt [expr {$xt + ([llength $currentparents] - 2) * $linespc}]
     }
@@ -859,6 +869,10 @@ proc drawcommitline {level} {
 			       -text $name -font $namefont]
     set linedtag($lineno) [$canv3 create text 3 $y1 -anchor w \
 			       -text $date -font $mainfont]
+
+    set olddlevel $level
+    set olddisplist $displist
+    set oldnlines [llength $displist]
 }
 
 proc drawtags {id x xt y1} {
@@ -913,46 +927,11 @@ proc drawtags {id x xt y1} {
     return $xt
 }
 
-proc updatetodo {level noshortcut} {
-    global currentparents ncleft todo
-    global mainline oldlevel oldtodo oldnlines
-    global canvy linespc mainline
-    global commitinfo lineno xspc1
-
-    set oldlevel $level
-    set oldtodo $todo
-    set oldnlines [llength $todo]
-    if {!$noshortcut && [llength $currentparents] == 1} {
-	set p [lindex $currentparents 0]
-	if {$ncleft($p) == 1 && [lsearch -exact $todo $p] < 0} {
-	    set ncleft($p) 0
-	    set x [xcoord $level $level $lineno]
-	    set y [expr $canvy - $linespc]
-	    set mainline($p) [list $x $y]
-	    set todo [lreplace $todo $level $level $p]
-	    set xspc1([expr {$lineno + 1}]) $xspc1($lineno)
-	    return 0
-	}
-    }
-
-    set todo [lreplace $todo $level $level]
-    set i $level
-    foreach p $currentparents {
-	incr ncleft($p) -1
-	set k [lsearch -exact $todo $p]
-	if {$k < 0} {
-	    set todo [linsert $todo $i $p]
-	    incr i
-	}
-    }
-    return 1
-}
-
 proc notecrossings {id lo hi corner} {
-    global oldtodo crossings cornercrossings
+    global olddisplist crossings cornercrossings
 
     for {set i $lo} {[incr i] < $hi} {} {
-	set p [lindex $oldtodo $i]
+	set p [lindex $olddisplist $i]
 	if {$p == {}} continue
 	if {$i == $corner} {
 	    if {![info exists cornercrossings($id)]
@@ -988,37 +967,218 @@ proc xcoord {i level ln} {
     return $x
 }
 
-proc drawslants {level} {
-    global canv mainline sidelines canvx0 canvy xspc1 xspc2 lthickness
-    global oldlevel oldtodo todo currentparents dupparents
+# it seems Tk can't draw arrows on the end of diagonal line segments...
+proc trimdiagend {line} {
+    while {[llength $line] > 4} {
+	set x1 [lindex $line end-3]
+	set y1 [lindex $line end-2]
+	set x2 [lindex $line end-1]
+	set y2 [lindex $line end]
+	if {($x1 == $x2) != ($y1 == $y2)} break
+	set line [lreplace $line end-1 end]
+    }
+    return $line
+}
+
+proc trimdiagstart {line} {
+    while {[llength $line] > 4} {
+	set x1 [lindex $line 0]
+	set y1 [lindex $line 1]
+	set x2 [lindex $line 2]
+	set y2 [lindex $line 3]
+	if {($x1 == $x2) != ($y1 == $y2)} break
+	set line [lreplace $line 0 1]
+    }
+    return $line
+}
+
+proc drawslants {id needonscreen nohs} {
+    global canv mainline mainlinearrow sidelines
+    global canvx0 canvy xspc1 xspc2 lthickness
+    global currentparents dupparents
     global lthickness linespc canvy colormap lineno geometry
-    global maxgraphpct
+    global maxgraphpct maxwidth
+    global displist onscreen lastuse
+    global parents commitlisted
+    global oldnlines olddlevel olddisplist
+    global nhyperspace numcommits nnewparents
+
+    if {$lineno < 0} {
+	lappend displist $id
+	set onscreen($id) 1
+	return 0
+    }
+
+    set y1 [expr {$canvy - $linespc}]
+    set y2 $canvy
+
+    # work out what we need to get back on screen
+    set reins {}
+    if {$onscreen($id) < 0} {
+	# next to do isn't displayed, better get it on screen...
+	lappend reins [list $id 0]
+    }
+    # make sure all the previous commits's parents are on the screen
+    foreach p $currentparents {
+	if {$onscreen($p) < 0} {
+	    lappend reins [list $p 0]
+	}
+    }
+    # bring back anything requested by caller
+    if {$needonscreen ne {}} {
+	lappend reins $needonscreen
+    }
+
+    # try the shortcut
+    if {$currentparents == $id && $onscreen($id) == 0 && $reins eq {}} {
+	set dlevel $olddlevel
+	set x [xcoord $dlevel $dlevel $lineno]
+	set mainline($id) [list $x $y1]
+	set mainlinearrow($id) none
+	set lastuse($id) $lineno
+	set displist [lreplace $displist $dlevel $dlevel $id]
+	set onscreen($id) 1
+	set xspc1([expr {$lineno + 1}]) $xspc1($lineno)
+	return $dlevel
+    }
+
+    # update displist
+    set displist [lreplace $displist $olddlevel $olddlevel]
+    set j $olddlevel
+    foreach p $currentparents {
+	set lastuse($p) $lineno
+	if {$onscreen($p) == 0} {
+	    set displist [linsert $displist $j $p]
+	    set onscreen($p) 1
+	    incr j
+	}
+    }
+    if {$onscreen($id) == 0} {
+	lappend displist $id
+    }
+
+    # remove the null entry if present
+    set nullentry [lsearch -exact $displist {}]
+    if {$nullentry >= 0} {
+	set displist [lreplace $displist $nullentry $nullentry]
+    }
+
+    # bring back the ones we need now (if we did it earlier
+    # it would change displist and invalidate olddlevel)
+    foreach pi $reins {
+	# test again in case of duplicates in reins
+	set p [lindex $pi 0]
+	if {$onscreen($p) < 0} {
+	    set onscreen($p) 1
+	    set lastuse($p) $lineno
+	    set displist [linsert $displist [lindex $pi 1] $p]
+	    incr nhyperspace -1
+	}
+    }
+
+    set lastuse($id) $lineno
+
+    # see if we need to make any lines jump off into hyperspace
+    set displ [llength $displist]
+    if {$displ > $maxwidth} {
+	set ages {}
+	foreach x $displist {
+	    lappend ages [list $lastuse($x) $x]
+	}
+	set ages [lsort -integer -index 0 $ages]
+	set k 0
+	while {$displ > $maxwidth} {
+	    set use [lindex $ages $k 0]
+	    set victim [lindex $ages $k 1]
+	    if {$use >= $lineno - 5} break
+	    incr k
+	    if {[lsearch -exact $nohs $victim] >= 0} continue
+	    set i [lsearch -exact $displist $victim]
+	    set displist [lreplace $displist $i $i]
+	    set onscreen($victim) -1
+	    incr nhyperspace
+	    incr displ -1
+	    if {$i < $nullentry} {
+		incr nullentry -1
+	    }
+	    set x [lindex $mainline($victim) end-1]
+	    lappend mainline($victim) $x $y1
+	    set line [trimdiagend $mainline($victim)]
+	    set arrow "last"
+	    if {$mainlinearrow($victim) ne "none"} {
+		set line [trimdiagstart $line]
+		set arrow "both"
+	    }
+	    lappend sidelines($victim) [list $line 1 $arrow]
+	    unset mainline($victim)
+	}
+    }
+
+    set dlevel [lsearch -exact $displist $id]
+
+    # If we are reducing, put in a null entry
+    if {$displ < $oldnlines} {
+	# does the next line look like a merge?
+	# i.e. does it have > 1 new parent?
+	if {$nnewparents($id) > 1} {
+	    set i [expr {$dlevel + 1}]
+	} elseif {$nnewparents([lindex $olddisplist $olddlevel]) == 0} {
+	    set i $olddlevel
+	    if {$nullentry >= 0 && $nullentry < $i} {
+		incr i -1
+	    }
+	} elseif {$nullentry >= 0} {
+	    set i $nullentry
+	    while {$i < $displ
+		   && [lindex $olddisplist $i] == [lindex $displist $i]} {
+		incr i
+	    }
+	} else {
+	    set i $olddlevel
+	    if {$dlevel >= $i} {
+		incr i
+	    }
+	}
+	if {$i < $displ} {
+	    set displist [linsert $displist $i {}]
+	    incr displ
+	    if {$dlevel >= $i} {
+		incr dlevel
+	    }
+	}
+    }
 
     # decide on the line spacing for the next line
     set lj [expr {$lineno + 1}]
     set maxw [expr {$maxgraphpct * $geometry(canv1) / 100}]
-    set n [llength $todo]
-    if {$n <= 1 || $canvx0 + $n * $xspc2 <= $maxw} {
+    if {$displ <= 1 || $canvx0 + $displ * $xspc2 <= $maxw} {
 	set xspc1($lj) $xspc2
     } else {
-	set xspc1($lj) [expr {($maxw - $canvx0 - $xspc2) / ($n - 1)}]
+	set xspc1($lj) [expr {($maxw - $canvx0 - $xspc2) / ($displ - 1)}]
 	if {$xspc1($lj) < $lthickness} {
 	    set xspc1($lj) $lthickness
 	}
     }
-    
-    set y1 [expr $canvy - $linespc]
-    set y2 $canvy
+
+    foreach idi $reins {
+	set id [lindex $idi 0]
+	set j [lsearch -exact $displist $id]
+	set xj [xcoord $j $dlevel $lj]
+	set mainline($id) [list $xj $y2]
+	set mainlinearrow($id) first
+    }
+
     set i -1
-    foreach id $oldtodo {
+    foreach id $olddisplist {
 	incr i
 	if {$id == {}} continue
-	set xi [xcoord $i $oldlevel $lineno]
-	if {$i == $oldlevel} {
+	if {$onscreen($id) <= 0} continue
+	set xi [xcoord $i $olddlevel $lineno]
+	if {$i == $olddlevel} {
 	    foreach p $currentparents {
-		set j [lsearch -exact $todo $p]
+		set j [lsearch -exact $displist $p]
 		set coords [list $xi $y1]
-		set xj [xcoord $j $level $lj]
+		set xj [xcoord $j $dlevel $lj]
 		if {$xj < $xi - $linespc} {
 		    lappend coords [expr {$xj + $linespc}] $y1
 		    notecrossings $p $j $i [expr {$j + 1}]
@@ -1029,9 +1189,10 @@ proc drawslants {level} {
 		if {[lsearch -exact $dupparents $p] >= 0} {
 		    # draw a double-width line to indicate the doubled parent
 		    lappend coords $xj $y2
-		    lappend sidelines($p) [list $coords 2]
+		    lappend sidelines($p) [list $coords 2 none]
 		    if {![info exists mainline($p)]} {
 			set mainline($p) [list $xj $y2]
+			set mainlinearrow($p) none
 		    }
 		} else {
 		    # normal case, no parent duplicated
@@ -1045,24 +1206,25 @@ proc drawslants {level} {
 			    lappend coords $xj $yb
 			}
 			set mainline($p) $coords
+			set mainlinearrow($p) none
 		    } else {
 			lappend coords $xj $yb
 			if {$yb < $y2} {
 			    lappend coords $xj $y2
 			}
-			lappend sidelines($p) [list $coords 1]
+			lappend sidelines($p) [list $coords 1 none]
 		    }
 		}
 	    }
 	} else {
 	    set j $i
-	    if {[lindex $todo $i] != $id} {
-		set j [lsearch -exact $todo $id]
+	    if {[lindex $displist $i] != $id} {
+		set j [lsearch -exact $displist $id]
 	    }
 	    if {$j != $i || $xspc1($lineno) != $xspc1($lj)
-		|| ($oldlevel <= $i && $i <= $level)
-		|| ($level <= $i && $i <= $oldlevel)} {
-		set xj [xcoord $j $level $lj]
+		|| ($olddlevel <= $i && $i <= $dlevel)
+		|| ($dlevel <= $i && $i <= $olddlevel)} {
+		set xj [xcoord $j $dlevel $lj]
 		set dx [expr {abs($xi - $xj)}]
 		set yb $y2
 		if {0 && $dx < $linespc} {
@@ -1072,21 +1234,152 @@ proc drawslants {level} {
 	    }
 	}
     }
+    return $dlevel
+}
+
+# search for x in a list of lists
+proc llsearch {llist x} {
+    set i 0
+    foreach l $llist {
+	if {$l == $x || [lsearch -exact $l $x] >= 0} {
+	    return $i
+	}
+	incr i
+    }
+    return -1
+}
+
+proc drawmore {reading} {
+    global displayorder numcommits ncmupdate nextupdate
+    global stopped nhyperspace parents commitlisted
+    global maxwidth onscreen displist currentparents olddlevel
+
+    set n [llength $displayorder]
+    while {$numcommits < $n} {
+	set id [lindex $displayorder $numcommits]
+	set ctxend [expr {$numcommits + 10}]
+	if {!$reading && $ctxend > $n} {
+	    set ctxend $n
+	}
+	set dlist {}
+	if {$numcommits > 0} {
+	    set dlist [lreplace $displist $olddlevel $olddlevel]
+	    set i $olddlevel
+	    foreach p $currentparents {
+		if {$onscreen($p) == 0} {
+		    set dlist [linsert $dlist $i $p]
+		    incr i
+		}
+	    }
+	}
+	set nohs {}
+	set reins {}
+	set isfat [expr {[llength $dlist] > $maxwidth}]
+	if {$nhyperspace > 0 || $isfat} {
+	    if {$ctxend > $n} break
+	    # work out what to bring back and
+	    # what we want to don't want to send into hyperspace
+	    set room 1
+	    for {set k $numcommits} {$k < $ctxend} {incr k} {
+		set x [lindex $displayorder $k]
+		set i [llsearch $dlist $x]
+		if {$i < 0} {
+		    set i [llength $dlist]
+		    lappend dlist $x
+		}
+		if {[lsearch -exact $nohs $x] < 0} {
+		    lappend nohs $x
+		}
+		if {$reins eq {} && $onscreen($x) < 0 && $room} {
+		    set reins [list $x $i]
+		}
+		set newp {}
+		if {[info exists commitlisted($x)]} {
+		    set right 0
+		    foreach p $parents($x) {
+			if {[llsearch $dlist $p] < 0} {
+			    lappend newp $p
+			    if {[lsearch -exact $nohs $p] < 0} {
+				lappend nohs $p
+			    }
+			    if {$reins eq {} && $onscreen($p) < 0 && $room} {
+				set reins [list $p [expr {$i + $right}]]
+			    }
+			}
+			set right 1
+		    }
+		}
+		set l [lindex $dlist $i]
+		if {[llength $l] == 1} {
+		    set l $newp
+		} else {
+		    set j [lsearch -exact $l $x]
+		    set l [concat [lreplace $l $j $j] $newp]
+		}
+		set dlist [lreplace $dlist $i $i $l]
+		if {$room && $isfat && [llength $newp] <= 1} {
+		    set room 0
+		}
+	    }
+	}
+
+	set dlevel [drawslants $id $reins $nohs]
+	drawcommitline $dlevel
+	if {[clock clicks -milliseconds] >= $nextupdate
+	    && $numcommits >= $ncmupdate} {
+	    doupdate $reading
+	    if {$stopped} break
+	}
+    }
+}
+
+# level here is an index in todo
+proc updatetodo {level noshortcut} {
+    global ncleft todo nnewparents
+    global commitlisted parents onscreen
+
+    set id [lindex $todo $level]
+    set olds {}
+    if {[info exists commitlisted($id)]} {
+	foreach p $parents($id) {
+	    if {[lsearch -exact $olds $p] < 0} {
+		lappend olds $p
+	    }
+	}
+    }
+    if {!$noshortcut && [llength $olds] == 1} {
+	set p [lindex $olds 0]
+	if {$ncleft($p) == 1 && [lsearch -exact $todo $p] < 0} {
+	    set ncleft($p) 0
+	    set todo [lreplace $todo $level $level $p]
+	    set onscreen($p) 0
+	    set nnewparents($id) 1
+	    return 0
+	}
+    }
+
+    set todo [lreplace $todo $level $level]
+    set i $level
+    set n 0
+    foreach p $olds {
+	incr ncleft($p) -1
+	set k [lsearch -exact $todo $p]
+	if {$k < 0} {
+	    set todo [linsert $todo $i $p]
+	    set onscreen($p) 0
+	    incr i
+	    incr n
+	}
+    }
+    set nnewparents($id) $n
+
+    return 1
 }
 
 proc decidenext {{noread 0}} {
-    global parents children nchildren ncleft todo
-    global canv canv2 canv3 mainfont namefont canvy linespc
+    global ncleft todo
     global datemode cdate
     global commitinfo
-    global currentparents oldlevel oldnlines oldtodo
-    global lineno lthickness
-
-    # remove the null entry if present
-    set nullentry [lsearch -exact $todo {}]
-    if {$nullentry >= 0} {
-	set todo [lreplace $todo $nullentry $nullentry]
-    }
 
     # choose which one to do next time around
     set todol [llength $todo]
@@ -1122,73 +1415,43 @@ proc decidenext {{noread 0}} {
 	return -1
     }
 
-    # If we are reducing, put in a null entry
-    if {$todol < $oldnlines} {
-	if {$nullentry >= 0} {
-	    set i $nullentry
-	    while {$i < $todol
-		   && [lindex $oldtodo $i] == [lindex $todo $i]} {
-		incr i
-	    }
-	} else {
-	    set i $oldlevel
-	    if {$level >= $i} {
-		incr i
-	    }
-	}
-	if {$i < $todol} {
-	    set todo [linsert $todo $i {}]
-	    if {$level >= $i} {
-		incr level
-	    }
-	}
-    }
     return $level
 }
 
 proc drawcommit {id} {
     global phase todo nchildren datemode nextupdate
-    global startcommits numcommits ncmupdate
+    global numcommits ncmupdate displayorder todo onscreen
 
     if {$phase != "incrdraw"} {
 	set phase incrdraw
-	set todo $id
-	set startcommits $id
+	set displayorder {}
+	set todo {}
 	initgraph
-	drawcommitline 0
-	updatetodo 0 $datemode
-    } else {
-	if {$nchildren($id) == 0} {
-	    lappend todo $id
-	    lappend startcommits $id
+    }
+    if {$nchildren($id) == 0} {
+	lappend todo $id
+	set onscreen($id) 0
+    }
+    set level [decidenext 1]
+    if {$level == {} || $id != [lindex $todo $level]} {
+	return
+    }
+    while 1 {
+	lappend displayorder [lindex $todo $level]
+	if {[updatetodo $level $datemode]} {
+	    set level [decidenext 1]
+	    if {$level == {}} break
 	}
-	set level [decidenext 1]
-	if {$level == {} || $id != [lindex $todo $level]} {
-	    return
-	}
-	while 1 {
-	    drawslants $level
-	    drawcommitline $level
-	    if {[updatetodo $level $datemode]} {
-		set level [decidenext 1]
-		if {$level == {}} break
-	    }
-	    set id [lindex $todo $level]
-	    if {![info exists commitlisted($id)]} {
-		break
-	    }
-	    if {[clock clicks -milliseconds] >= $nextupdate
-		&& $numcommits >= $ncmupdate} {
-		doupdate 1
-		if {$stopped} break
-	    }
+	set id [lindex $todo $level]
+	if {![info exists commitlisted($id)]} {
+	    break
 	}
     }
+    drawmore 1
 }
 
 proc finishcommits {} {
     global phase
-    global startcommits
     global canv mainfont ctext maincursor textcursor
 
     if {$phase != "incrdraw"} {
@@ -1197,9 +1460,7 @@ proc finishcommits {} {
 	    -font $mainfont -tags textitems
 	set phase {}
     } else {
-	set level [decidenext]
-	drawslants $level
-	drawrest $level [llength $startcommits]
+	drawrest
     }
     . config -cursor $maincursor
     settextcursor $textcursor
@@ -1217,54 +1478,38 @@ proc settextcursor {c} {
 }
 
 proc drawgraph {} {
-    global nextupdate startmsecs startcommits todo ncmupdate
+    global nextupdate startmsecs ncmupdate
+    global displayorder onscreen
 
-    if {$startcommits == {}} return
+    if {$displayorder == {}} return
     set startmsecs [clock clicks -milliseconds]
     set nextupdate [expr $startmsecs + 100]
     set ncmupdate 1
     initgraph
-    set todo [lindex $startcommits 0]
-    drawrest 0 1
+    foreach id $displayorder {
+	set onscreen($id) 0
+    }
+    drawmore 0
 }
 
-proc drawrest {level startix} {
+proc drawrest {} {
     global phase stopped redisplaying selectedline
-    global datemode currentparents todo
+    global datemode todo displayorder
     global numcommits ncmupdate
-    global nextupdate startmsecs startcommits idline
+    global nextupdate startmsecs idline
 
+    set level [decidenext]
     if {$level >= 0} {
 	set phase drawgraph
-	set startid [lindex $startcommits $startix]
-	set startline -1
-	if {$startid != {}} {
-	    set startline $idline($startid)
-	}
 	while 1 {
-	    if {$stopped} break
-	    drawcommitline $level
+	    lappend displayorder [lindex $todo $level]
 	    set hard [updatetodo $level $datemode]
-	    if {$numcommits == $startline} {
-		lappend todo $startid
-		set hard 1
-		incr startix
-		set startid [lindex $startcommits $startix]
-		set startline -1
-		if {$startid != {}} {
-		    set startline $idline($startid)
-		}
-	    }
 	    if {$hard} {
 		set level [decidenext]
 		if {$level < 0} break
-		drawslants $level
-	    }
-	    if {[clock clicks -milliseconds] >= $nextupdate
-	        && $numcommits >= $ncmupdate} {
-		doupdate 0
 	    }
 	}
+	drawmore 0
     }
     set phase {}
     set drawmsecs [expr [clock clicks -milliseconds] - $startmsecs]
@@ -1776,7 +2021,7 @@ proc commit_descriptor {p} {
 proc selectline {l isnew} {
     global canv canv2 canv3 ctext commitinfo selectedline
     global lineid linehtag linentag linedtag
-    global canvy0 linespc parents nparents children nchildren
+    global canvy0 linespc parents nparents children
     global cflist currentid sha1entry
     global commentend idtags idline
 
@@ -2700,12 +2945,13 @@ proc listboxsel {} {
 
 proc setcoords {} {
     global linespc charspc canvx0 canvy0 mainfont
-    global xspc1 xspc2
+    global xspc1 xspc2 lthickness
 
     set linespc [font metrics $mainfont -linespace]
     set charspc [font measure $mainfont "m"]
     set canvy0 [expr 3 + 0.5 * $linespc]
     set canvx0 [expr 3 + 0.5 * $linespc]
+    set lthickness [expr {int($linespc / 9) + 1}]
     set xspc1(0) $linespc
     set xspc2 $linespc
 }
@@ -3216,6 +3462,7 @@ set textfont {Courier 9}
 set findmergefiles 0
 set gaudydiff 0
 set maxgraphpct 50
+set maxwidth 16
 
 set colors {green red blue magenta darkgrey brown orange}