X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=gitk;h=f1ea4e1e432010f9a049fe91b305d09f44589280;hb=40a10462498bdd23d4e49f02867b8be50eb78704;hp=edf94bf4c46570245feaf87fa64f94eab72aec1c;hpb=fa4da7b32e1197fa5032db6a2de7749868253f8b;p=git.git

diff --git a/gitk b/gitk
index edf94bf4..f1ea4e1e 100755
--- a/gitk
+++ b/gitk
@@ -1,6 +1,6 @@
 #!/bin/sh
 # Tcl ignores the next line -*- tcl -*- \
-exec wish "$0" -- "${1+$@}"
+exec wish "$0" -- "$@"
 
 # Copyright (C) 2005 Paul Mackerras.  All rights reserved.
 # This program is free software; it may be used, copied, modified
@@ -18,7 +18,7 @@ proc gitdir {} {
 
 proc getcommits {rargs} {
     global commits commfd phase canv mainfont env
-    global startmsecs nextupdate
+    global startmsecs nextupdate ncmupdate
     global ctext maincursor textcursor leftover
 
     # check that we can find a .git directory somewhere...
@@ -31,6 +31,7 @@ proc getcommits {rargs} {
     set phase getcommits
     set startmsecs [clock clicks -milliseconds]
     set nextupdate [expr $startmsecs + 100]
+    set ncmupdate 1
     if [catch {
 	set parse_args [concat --default HEAD $rargs]
 	set parsed_args [split [eval exec git-rev-parse $parse_args] "\n"]
@@ -42,14 +43,14 @@ proc getcommits {rargs} {
 	set parsed_args $rargs
     }
     if [catch {
-	set commfd [open "|git-rev-list --header --topo-order $parsed_args" r]
+	set commfd [open "|git-rev-list --header --topo-order --parents $parsed_args" r]
     } err] {
 	puts stderr "Error executing git-rev-list: $err"
 	exit 1
     }
     set leftover {}
     fconfigure $commfd -blocking 0 -translation lf
-    fileevent $commfd readable "getcommitlines $commfd"
+    fileevent $commfd readable [list getcommitlines $commfd]
     $canv delete all
     $canv create text 3 3 -anchor nw -text "Reading commits..." \
 	-font $mainfont -tags textitems
@@ -58,7 +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
 
@@ -95,7 +96,19 @@ to allow selection of commits to be displayed.)}
 	    set leftover {}
 	}
 	set start [expr {$i + 1}]
-	if {![regexp {^([0-9a-f]{40})\n} $cmit match id]} {
+	set j [string first "\n" $cmit]
+	set ok 0
+	if {$j >= 0} {
+	    set ids [string range $cmit 0 [expr {$j - 1}]]
+	    set ok 1
+	    foreach id $ids {
+		if {![regexp {^[0-9a-f]{40}$} $id]} {
+		    set ok 0
+		    break
+		}
+	    }
+	}
+	if {!$ok} {
 	    set shortcmit $cmit
 	    if {[string length $shortcmit] > 80} {
 		set shortcmit "[string range $shortcmit 0 80]..."
@@ -103,13 +116,15 @@ to allow selection of commits to be displayed.)}
 	    error_popup "Can't parse git-rev-list output: {$shortcmit}"
 	    exit 1
 	}
-	set cmit [string range $cmit 41 end]
+	set id [lindex $ids 0]
+	set olds [lrange $ids 1 end]
+	set cmit [string range $cmit [expr {$j + 1}] end]
 	lappend commits $id
 	set commitlisted($id) 1
-	parsecommit $id $cmit 1
+	parsecommit $id $cmit 1 [lrange $ids 1 end]
 	drawcommit $id
 	if {[clock clicks -milliseconds] >= $nextupdate} {
-	    doupdate
+	    doupdate 1
 	}
 	while {$redisplaying} {
 	    set redisplaying 0
@@ -120,7 +135,7 @@ to allow selection of commits to be displayed.)}
 		    drawcommit $id
 		    if {$stopped} break
 		    if {[clock clicks -milliseconds] >= $nextupdate} {
-			doupdate
+			doupdate 1
 		    }
 		}
 	    }
@@ -128,21 +143,32 @@ to allow selection of commits to be displayed.)}
     }
 }
 
-proc doupdate {} {
-    global commfd nextupdate
+proc doupdate {reading} {
+    global commfd nextupdate numcommits ncmupdate
 
-    incr nextupdate 100
-    fileevent $commfd readable {}
+    if {$reading} {
+	fileevent $commfd readable {}
+    }
     update
-    fileevent $commfd readable "getcommitlines $commfd"
+    set nextupdate [expr {[clock clicks -milliseconds] + 100}]
+    if {$numcommits < 100} {
+	set ncmupdate [expr {$numcommits + 1}]
+    } elseif {$numcommits < 10000} {
+	set ncmupdate [expr {$numcommits + 10}]
+    } else {
+	set ncmupdate [expr {$numcommits + 100}]
+    }
+    if {$reading} {
+	fileevent $commfd readable [list getcommitlines $commfd]
+    }
 }
 
 proc readcommit {id} {
     if [catch {set contents [exec git-cat-file commit $id]}] return
-    parsecommit $id $contents 0
+    parsecommit $id $contents 0 {}
 }
 
-proc parsecommit {id contents listed} {
+proc parsecommit {id contents listed olds} {
     global commitinfo children nchildren parents nparents cdate ncleft
 
     set inhdr 1
@@ -157,30 +183,26 @@ proc parsecommit {id contents listed} {
 	set nchildren($id) 0
 	set ncleft($id) 0
     }
-    set parents($id) {}
-    set nparents($id) 0
+    set parents($id) $olds
+    set nparents($id) [llength $olds]
+    foreach p $olds {
+	if {![info exists nchildren($p)]} {
+	    set children($p) [list $id]
+	    set nchildren($p) 1
+	    set ncleft($p) 1
+	} elseif {[lsearch -exact $children($p) $id] < 0} {
+	    lappend children($p) $id
+	    incr nchildren($p)
+	    incr ncleft($p)
+	}
+    }
     foreach line [split $contents "\n"] {
 	if {$inhdr} {
 	    if {$line == {}} {
 		set inhdr 0
 	    } else {
 		set tag [lindex $line 0]
-		if {$tag == "parent"} {
-		    set p [lindex $line 1]
-		    if {![info exists nchildren($p)]} {
-			set children($p) {}
-			set nchildren($p) 0
-			set ncleft($p) 0
-		    }
-		    lappend parents($id) $p
-		    incr nparents($id)
-		    # sometimes we get a commit that lists a parent twice...
-		    if {$listed && [lsearch -exact $children($p) $id] < 0} {
-			lappend children($p) $id
-			incr nchildren($p)
-			incr ncleft($p)
-		    }
-		} elseif {$tag == "author"} {
+		if {$tag == "author"} {
 		    set x [expr {[llength $line] - 2}]
 		    set audate [lindex $line $x]
 		    set auname [lrange $line 1 [expr {$x - 1}]]
@@ -216,7 +238,8 @@ proc parsecommit {id contents listed} {
 }
 
 proc readrefs {} {
-    global tagids idtags headids idheads
+    global tagids idtags headids idheads tagcontents
+
     set tags [glob -nocomplain -types f [gitdir]/refs/tags/*]
     foreach f $tags {
 	catch {
@@ -226,7 +249,8 @@ proc readrefs {} {
 		set direct [file tail $f]
 		set tagids($direct) $id
 		lappend idtags($id) $direct
-		set contents [split [exec git-cat-file tag $id] "\n"]
+		set tagblob [exec git-cat-file tag $id]
+		set contents [split $tagblob "\n"]
 		set obj {}
 		set type {}
 		set tag {}
@@ -241,6 +265,7 @@ proc readrefs {} {
 		if {$obj != {} && $type == "commit" && $tag != {}} {
 		    set tagids($tag) $obj
 		    lappend idtags($obj) $tag
+		    set tagcontents($tag) $tagblob
 		}
 	    }
 	    close $fd
@@ -259,6 +284,32 @@ proc readrefs {} {
 	    close $fd
 	}
     }
+    readotherrefs refs {} {tags heads}
+}
+
+proc readotherrefs {base dname excl} {
+    global otherrefids idotherrefs
+
+    set git [gitdir]
+    set files [glob -nocomplain -types f [file join $git $base *]]
+    foreach f $files {
+	catch {
+	    set fd [open $f r]
+	    set line [read $fd 40]
+	    if {[regexp {^[0-9a-f]{40}} $line id]} {
+		set name "$dname[file tail $f]"
+		set otherrefids($name) $id
+		lappend idotherrefs($id) $name
+	    }
+	    close $fd
+	}
+    }
+    set dirs [glob -nocomplain -types d [file join $git $base *]]
+    foreach d $dirs {
+	set dir [file tail $d]
+	if {[lsearch -exact $excl $dir] >= 0} continue
+	readotherrefs [file join $base $dir] "$dname$dir/" {}
+    }
 }
 
 proc error_popup msg {
@@ -283,6 +334,7 @@ proc makewindow {} {
     menu .bar
     .bar add cascade -label "File" -menu .bar.file
     menu .bar.file
+    .bar.file add command -label "Reread references" -command rereadrefs
     .bar.file add command -label "Quit" -command doquit
     menu .bar.help
     .bar add cascade -label "Help" -menu .bar.help
@@ -387,7 +439,7 @@ proc makewindow {} {
     set ctext .ctop.cdet.left.ctext
     text $ctext -bg white -state disabled -font $textfont \
 	-width $geometry(ctextw) -height $geometry(ctexth) \
-	-yscrollcommand ".ctop.cdet.left.sb set"
+	-yscrollcommand ".ctop.cdet.left.sb set" -wrap none
     scrollbar .ctop.cdet.left.sb -command "$ctext yview"
     pack .ctop.cdet.left.sb -side right -fill y
     pack $ctext -side left -fill both -expand 1
@@ -434,6 +486,8 @@ proc makewindow {} {
     bindall <B2-Motion> "allcanvs scan dragto 0 %y"
     bind . <Key-Up> "selnextline -1"
     bind . <Key-Down> "selnextline 1"
+    bind . <Key-Right> "goforw"
+    bind . <Key-Left> "goback"
     bind . <Key-Prior> "allcanvs yview scroll -1 pages"
     bind . <Key-Next> "allcanvs yview scroll 1 pages"
     bindkey <Key-Delete> "$ctext yview scroll -1 pages"
@@ -441,6 +495,12 @@ proc makewindow {} {
     bindkey <Key-space> "$ctext yview scroll 1 pages"
     bindkey p "selnextline -1"
     bindkey n "selnextline 1"
+    bindkey z "goback"
+    bindkey x "goforw"
+    bindkey i "selnextline -1"
+    bindkey k "selnextline 1"
+    bindkey j "goback"
+    bindkey l "goforw"
     bindkey b "$ctext yview scroll -1 pages"
     bindkey d "$ctext yview scroll 18 units"
     bindkey u "$ctext yview scroll -18 units"
@@ -506,6 +566,7 @@ proc click {w} {
 proc savestuff {w} {
     global canv canv2 canv3 ctext cflist mainfont textfont
     global stuffsaved findmergefiles gaudydiff maxgraphpct
+    global maxwidth
 
     if {$stuffsaved} return
     if {![winfo viewable .]} return
@@ -516,6 +577,7 @@ proc savestuff {w} {
 	puts $f [list set findmergefiles $findmergefiles]
 	puts $f [list set gaudydiff $gaudydiff]
 	puts $f [list set maxgraphpct $maxgraphpct]
+	puts $f [list set maxwidth $maxwidth]
 	puts $f "set geometry(width) [winfo width .ctop]"
 	puts $f "set geometry(height) [winfo height .ctop]"
 	puts $f "set geometry(canv1) [expr [winfo width $canv]-2]"
@@ -692,21 +754,24 @@ 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} {
@@ -718,19 +783,47 @@ proc bindline {t id} {
     $canv bind $t <Button-1> "lineclick %x %y $id 1"
 }
 
+proc drawlines {id xtra} {
+    global mainline mainlinearrow sidelines lthickness colormap canv
+
+    $canv delete lines.$id
+    if {[info exists mainline($id)]} {
+	set t [$canv create line $mainline($id) \
+		   -width [expr {($xtra + 1) * $lthickness}] \
+		   -fill $colormap($id) -tags lines.$id \
+		   -arrow $mainlinearrow($id)]
+	$canv lower $t
+	bindline $t $id
+    }
+    if {[info exists sidelines($id)]} {
+	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 + $xtra) * $lthickness}] \
+		       -arrow $arrow -tags lines.$id]
+	    $canv lower $t
+	    bindline $t $id
+	}
+    }
+}
+
+# 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 idtags idline idheads idotherrefs
+    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"}]
@@ -761,34 +854,25 @@ proc drawcommitline {level} {
 	[list 0 0 0 [expr $y1 + 0.5 * $linespc + 2]]
     if {[info exists mainline($id)]} {
 	lappend mainline($id) $x $y1
-	set t [$canv create line $mainline($id) \
-		   -width $lthickness -fill $colormap($id)]
-	$canv lower $t
-	bindline $t $id
-    }
-    if {[info exists sidelines($id)]} {
-	foreach ls $sidelines($id) {
-	    set coords [lindex $ls 0]
-	    set thick [lindex $ls 1]
-	    set t [$canv create line $coords -fill $colormap($id) \
-		       -width [expr {$thick * $lthickness}]]
-	    $canv lower $t
-	    bindline $t $id
+	if {$mainlinearrow($id) ne "none"} {
+	    set mainline($id) [trimdiagstart $mainline($id)]
 	}
     }
+    drawlines $id 0
     set orad [expr {$linespc / 3}]
     set t [$canv create oval [expr $x - $orad] [expr $y1 - $orad] \
 	       [expr $x + $orad - 1] [expr $y1 + $orad - 1] \
 	       -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) * $linespc}]
     }
     set rowtextx($lineno) $xt
     set idpos($id) [list $x $xt $y1]
-    if {[info exists idtags($id)] || [info exists idheads($id)]} {
+    if {[info exists idtags($id)] || [info exists idheads($id)]
+	|| [info exists idotherrefs($id)]} {
 	set xt [drawtags $id $x $xt $y1]
     }
     set headline [lindex $commitinfo($id) 0]
@@ -801,21 +885,30 @@ 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} {
-    global idtags idheads
+    global idtags idheads idotherrefs
     global linespc lthickness
-    global canv mainfont
+    global canv mainfont idline rowtextx
 
     set marks {}
     set ntags 0
+    set nheads 0
     if {[info exists idtags($id)]} {
 	set marks $idtags($id)
 	set ntags [llength $marks]
     }
     if {[info exists idheads($id)]} {
 	set marks [concat $marks $idheads($id)]
+	set nheads [llength $idheads($id)]
+    }
+    if {[info exists idotherrefs($id)]} {
+	set marks [concat $marks $idotherrefs($id)]
     }
     if {$marks eq {}} {
 	return $xt
@@ -840,61 +933,36 @@ proc drawtags {id x xt y1} {
 	set xr [expr $x + $delta + $wid + $lthickness]
 	if {[incr ntags -1] >= 0} {
 	    # draw a tag
-	    $canv create polygon $x [expr $yt + $delta] $xl $yt\
-		$xr $yt $xr $yb $xl $yb $x [expr $yb - $delta] \
-		-width 1 -outline black -fill yellow -tags tag.$id
+	    set t [$canv create polygon $x [expr $yt + $delta] $xl $yt \
+		       $xr $yt $xr $yb $xl $yb $x [expr $yb - $delta] \
+		       -width 1 -outline black -fill yellow -tags tag.$id]
+	    $canv bind $t <1> [list showtag $tag 1]
+	    set rowtextx($idline($id)) [expr {$xr + $linespc}]
 	} else {
-	    # draw a head
+	    # draw a head or other ref
+	    if {[incr nheads -1] >= 0} {
+		set col green
+	    } else {
+		set col "#ddddff"
+	    }
 	    set xl [expr $xl - $delta/2]
 	    $canv create polygon $x $yt $xr $yt $xr $yb $x $yb \
-		-width 1 -outline black -fill green -tags tag.$id
-	}
-	$canv create text $xl $y1 -anchor w -text $tag \
-	    -font $mainfont -tags tag.$id
-    }
-    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
+		-width 1 -outline black -fill $col -tags tag.$id
 	}
-    }
-
-    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 $p]
-	    incr i
+	set t [$canv create text $xl $y1 -anchor w -text $tag \
+		   -font $mainfont -tags tag.$id]
+	if {$ntags >= 0} {
+	    $canv bind $t <1> [list showtag $tag 1]
 	}
     }
-    return 1
+    return $xt
 }
 
 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)]
@@ -930,37 +998,219 @@ 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 $id
+	set onscreen($id) 1
+    }
+
+    # 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}]
@@ -971,9 +1221,10 @@ 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
@@ -987,48 +1238,175 @@ 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 $lj]
-		set dx [expr {abs($xi - $xj)}]
-		set yb $y2
-		if {0 && $dx < $linespc} {
-		    set yb [expr {$y1 + $dx}]
+		|| ($olddlevel < $i && $i < $dlevel)
+		|| ($dlevel < $i && $i < $olddlevel)} {
+		set xj [xcoord $j $dlevel $lj]
+		lappend mainline($id) $xi $y1 $xj $y2
+	    }
+	}
+    }
+    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 $newp] <= 1} {
+		    set room 0
 		}
-		lappend mainline($id) $xi $y1 $xj $yb
 	    }
 	}
+
+	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]
@@ -1064,72 +1442,43 @@ 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
+    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 $id
-	}
-	set level [decidenext 1]
-	if {$level == {} || $id != [lindex $todo $level]} {
-	    return
+    }
+    if {$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
 	}
-	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] >= $nextupdate} {
-		doupdate
-		if {$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"} {
@@ -1138,9 +1487,7 @@ proc finishcommits {} {
 	    -font $mainfont -tags textitems
 	set phase {}
     } else {
-	set level [decidenext]
-	drawslants $level
-	drawrest $level [llength $startcommits]
+	drawrest
     }
     . config -cursor $maincursor
     settextcursor $textcursor
@@ -1158,53 +1505,38 @@ proc settextcursor {c} {
 }
 
 proc drawgraph {} {
-    global nextupdate startmsecs startcommits todo
+    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 numcommits
-    global nextupdate startmsecs startcommits idline
+    global datemode todo displayorder
+    global numcommits ncmupdate
+    global nextupdate startmsecs
 
+    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} {
-		update
-		incr nextupdate 100
 	    }
 	}
+	drawmore 0
     }
     set phase {}
     set drawmsecs [expr [clock clicks -milliseconds] - $startmsecs]
@@ -1704,14 +2036,49 @@ proc selcanvline {w x y} {
     selectline $l 1
 }
 
+proc commit_descriptor {p} {
+    global commitinfo
+    set l "..."
+    if {[info exists commitinfo($p)]} {
+	set l [lindex $commitinfo($p) 0]
+    }
+    return "$p ($l)"
+}
+
+# append some text to the ctext widget, and make any SHA1 ID
+# that we know about be a clickable link.
+proc appendwithlinks {text} {
+    global ctext idline linknum
+
+    set start [$ctext index "end - 1c"]
+    $ctext insert end $text
+    $ctext insert end "\n"
+    set links [regexp -indices -all -inline {[0-9a-f]{40}} $text]
+    foreach l $links {
+	set s [lindex $l 0]
+	set e [lindex $l 1]
+	set linkid [string range $text $s $e]
+	if {![info exists idline($linkid)]} continue
+	incr e
+	$ctext tag add link "$start + $s c" "$start + $e c"
+	$ctext tag add link$linknum "$start + $s c" "$start + $e c"
+	$ctext tag bind link$linknum <1> [list selectline $idline($linkid) 1]
+	incr linknum
+    }
+    $ctext tag conf link -foreground blue -underline 1
+    $ctext tag bind link <Enter> { %W configure -cursor hand2 }
+    $ctext tag bind link <Leave> { %W configure -cursor $curtextcursor }
+}
+
 proc selectline {l isnew} {
     global canv canv2 canv3 ctext commitinfo selectedline
     global lineid linehtag linentag linedtag
-    global canvy0 linespc parents nparents
+    global canvy0 linespc parents nparents children
     global cflist currentid sha1entry
-    global commentend idtags idline
+    global commentend idtags idline linknum
 
     $canv delete hover
+    normalline
     if {![info exists lineid($l)] || ![info exists linehtag($l)]} return
     $canv delete secsel
     set t [eval $canv create rect [$canv bbox $linehtag($l)] -outline {{}} \
@@ -1775,6 +2142,7 @@ proc selectline {l isnew} {
 
     $ctext conf -state normal
     $ctext delete 0.0 end
+    set linknum 0
     $ctext mark set fmark.0 0.0
     $ctext mark gravity fmark.0 left
     set info $commitinfo($id)
@@ -1788,40 +2156,22 @@ proc selectline {l isnew} {
 	$ctext insert end "\n"
     }
  
-    set commentstart [$ctext index "end - 1c"]
     set comment {}
-    foreach p $parents($id) {
-	set l "..."
-	if {[info exists commitinfo($p)]} {
-	    set l [lindex $commitinfo($p) 0]
-	    if {[string length $l] > 32} {
-		set l "[string range $l 0 28] ..."
-	    }
+    if {[info exists parents($id)]} {
+	foreach p $parents($id) {
+	    append comment "Parent: [commit_descriptor $p]\n"
+	}
+    }
+    if {[info exists children($id)]} {
+	foreach c $children($id) {
+	    append comment "Child:  [commit_descriptor $c]\n"
 	}
-	append comment "Parent: $p  ($l)\n"
     }
     append comment "\n"
     append comment [lindex $info 5]
-    $ctext insert end $comment
-    $ctext insert end "\n"
 
     # make anything that looks like a SHA1 ID be a clickable link
-    set links [regexp -indices -all -inline {[0-9a-f]{40}} $comment]
-    set i 0
-    foreach l $links {
-	set s [lindex $l 0]
-	set e [lindex $l 1]
-	set linkid [string range $comment $s $e]
-	if {![info exists idline($linkid)]} continue
-	incr e
-	$ctext tag add link "$commentstart + $s c" "$commentstart + $e c"
-	$ctext tag add link$i "$commentstart + $s c" "$commentstart + $e c"
-	$ctext tag bind link$i <1> [list selectline $idline($linkid) 1]
-	incr i
-    }
-    $ctext tag conf link -foreground blue -underline 1
-    $ctext tag bind link <Enter> { %W configure -cursor hand2 }
-    $ctext tag bind link <Leave> { %W configure -cursor $curtextcursor }
+    appendwithlinks $comment
 
     $ctext tag delete Comments
     $ctext tag remove found 1.0 end
@@ -2631,12 +2981,13 @@ 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
 }
@@ -2796,15 +3147,102 @@ proc linehover {} {
     $canv raise $t
 }
 
+proc clickisonarrow {id y} {
+    global mainline mainlinearrow sidelines lthickness
+
+    set thresh [expr {2 * $lthickness + 6}]
+    if {[info exists mainline($id)]} {
+	if {$mainlinearrow($id) ne "none"} {
+	    if {abs([lindex $mainline($id) 1] - $y) < $thresh} {
+		return "up"
+	    }
+	}
+    }
+    if {[info exists sidelines($id)]} {
+	foreach ls $sidelines($id) {
+	    set coords [lindex $ls 0]
+	    set arrow [lindex $ls 2]
+	    if {$arrow eq "first" || $arrow eq "both"} {
+		if {abs([lindex $coords 1] - $y) < $thresh} {
+		    return "up"
+		}
+	    }
+	    if {$arrow eq "last" || $arrow eq "both"} {
+		if {abs([lindex $coords end] - $y) < $thresh} {
+		    return "down"
+		}
+	    }
+	}
+    }
+    return {}
+}
+
+proc arrowjump {id dirn y} {
+    global mainline sidelines canv
+
+    set yt {}
+    if {$dirn eq "down"} {
+	if {[info exists mainline($id)]} {
+	    set y1 [lindex $mainline($id) 1]
+	    if {$y1 > $y} {
+		set yt $y1
+	    }
+	}
+	if {[info exists sidelines($id)]} {
+	    foreach ls $sidelines($id) {
+		set y1 [lindex $ls 0 1]
+		if {$y1 > $y && ($yt eq {} || $y1 < $yt)} {
+		    set yt $y1
+		}
+	    }
+	}
+    } else {
+	if {[info exists sidelines($id)]} {
+	    foreach ls $sidelines($id) {
+		set y1 [lindex $ls 0 end]
+		if {$y1 < $y && ($yt eq {} || $y1 > $yt)} {
+		    set yt $y1
+		}
+	    }
+	}
+    }
+    if {$yt eq {}} return
+    set ymax [lindex [$canv cget -scrollregion] 3]
+    if {$ymax eq {} || $ymax <= 0} return
+    set view [$canv yview]
+    set yspan [expr {[lindex $view 1] - [lindex $view 0]}]
+    set yfrac [expr {$yt / $ymax - $yspan / 2}]
+    if {$yfrac < 0} {
+	set yfrac 0
+    }
+    $canv yview moveto $yfrac
+}
+
 proc lineclick {x y id isnew} {
-    global ctext commitinfo children cflist canv
+    global ctext commitinfo children cflist canv thickerline
 
     unmarkmatches
     unselectline
+    normalline
+    $canv delete hover
+    # draw this line thicker than normal
+    drawlines $id 1
+    set thickerline $id
     if {$isnew} {
-	addtohistory [list lineclick $x $x $id 0]
+	set ymax [lindex [$canv cget -scrollregion] 3]
+	if {$ymax eq {}} return
+	set yfrac [lindex [$canv yview] 0]
+	set y [expr {$y + $yfrac * $ymax}]
+    }
+    set dirn [clickisonarrow $id $y]
+    if {$dirn ne {}} {
+	arrowjump $id $dirn $y
+	return
+    }
+
+    if {$isnew} {
+	addtohistory [list lineclick $x $y $id 0]
     }
-    $canv delete hover
     # fill the details pane with info about this line
     $ctext conf -state normal
     $ctext delete 0.0 end
@@ -2837,6 +3275,14 @@ proc lineclick {x y id isnew} {
     $cflist delete 0 end
 }
 
+proc normalline {} {
+    global thickerline
+    if {[info exists thickerline]} {
+	drawlines $thickerline 0
+	unset thickerline
+    }
+}
+
 proc selbyid {id} {
     global idline
     if {[info exists idline($id)]} {
@@ -3030,7 +3476,6 @@ proc mktag {} {
 
 proc domktag {} {
     global mktagtop env tagids idtags
-    global idpos idline linehtag canv selectedline
 
     set id [$mktagtop.sha1 get]
     set tag [$mktagtop.tag get]
@@ -3055,6 +3500,13 @@ proc domktag {} {
 
     set tagids($tag) $id
     lappend idtags($id) $tag
+    redrawtags $id
+}
+
+proc redrawtags {id} {
+    global canv linehtag idline idpos selectedline
+
+    if {![info exists idline($id)]} return
     $canv delete tag.$id
     set xt [eval drawtags $id $idpos($id)]
     $canv coords $linehtag($idline($id)) $xt [lindex $idpos($id) 2]
@@ -3130,6 +3582,68 @@ proc wrcomcan {} {
     unset wrcomtop
 }
 
+proc listrefs {id} {
+    global idtags idheads idotherrefs
+
+    set x {}
+    if {[info exists idtags($id)]} {
+	set x $idtags($id)
+    }
+    set y {}
+    if {[info exists idheads($id)]} {
+	set y $idheads($id)
+    }
+    set z {}
+    if {[info exists idotherrefs($id)]} {
+	set z $idotherrefs($id)
+    }
+    return [list $x $y $z]
+}
+
+proc rereadrefs {} {
+    global idtags idheads idotherrefs
+    global tagids headids otherrefids
+
+    set refids [concat [array names idtags] \
+		    [array names idheads] [array names idotherrefs]]
+    foreach id $refids {
+	if {![info exists ref($id)]} {
+	    set ref($id) [listrefs $id]
+	}
+    }
+    foreach v {tagids idtags headids idheads otherrefids idotherrefs} {
+	catch {unset $v}
+    }
+    readrefs
+    set refids [lsort -unique [concat $refids [array names idtags] \
+			[array names idheads] [array names idotherrefs]]]
+    foreach id $refids {
+	set v [listrefs $id]
+	if {![info exists ref($id)] || $ref($id) != $v} {
+	    redrawtags $id
+	}
+    }
+}
+
+proc showtag {tag isnew} {
+    global ctext cflist tagcontents tagids linknum
+
+    if {$isnew} {
+	addtohistory [list showtag $tag 0]
+    }
+    $ctext conf -state normal
+    $ctext delete 0.0 end
+    set linknum 0
+    if {[info exists tagcontents($tag)]} {
+	set text $tagcontents($tag)
+    } else {
+	set text "Tag: $tag\nId:  $tagids($tag)"
+    }
+    appendwithlinks $text
+    $ctext conf -state disabled
+    $cflist delete 0 end
+}
+
 proc doquit {} {
     global stopped
     set stopped 100
@@ -3147,6 +3661,7 @@ 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}