Switched from pack to grid; Demos are put in a namespace

1 files changed, 243 insertions, 236 deletions

diff --git a/demos/curveBezier.tcl b/demos/curveBezier.tcl
index 2cc0a6d..32245b8 100644
--- a/demos/curveBezier.tcl
+++ b/demos/curveBezier.tcl
@@ -6,254 +6,261 @@ if {![info exists zincDemo]} {
 }
 
 
-set w .curveBezier
-catch {destroy $w}
-toplevel $w
-wm title $w "Zinc Curve Bezier Demonstration"
-wm iconname $w Curve
-
-set defaultfont [font create -family Helvetica -size 10 -weight bold]
-#set imagePath [file join $zinc_library demos images]
-#set texture [image create photo -file [file join $imagePath paper-grey1.gif]]
-set splineColor \#AA0000
-set handleColor grey70
-set barColor grey30
-set textColor grey20
-
-frame $w.buttons
-pack $w.buttons -side bottom -fill x -pady 2m
-button $w.buttons.dismiss -text Dismiss -command "destroy $w"
-button $w.buttons.code -text "See Code" -command "showCode $w"
-pack $w.buttons.dismiss $w.buttons.code -side left -expand 1
-
-
-text $w.text -relief sunken -borderwidth 2 -setgrid true -height 3
-pack $w.text -expand yes -fill both
-
-$w.text insert 0.0 {
-6 examples of curves containing control points are displayed 
- with the list of control points written just below.
-You can move the handles to modify the bezier curves
-}
+namespace eval curveBezier {
+    variable w .curveBezier
+    catch {destroy $w}
+    toplevel $w
+    wm title $w "Zinc Curve Bezier Demonstration"
+    wm iconname $w Curve
+
+    variable defaultfont [font create -family Helvetica -size 10 -weight bold]
+    #variable imagePath [file join $zinc_library demos images]
+    #variable texture [image create photo -file [file join $imagePath paper-grey1.gif]]
+    variable splineColor \#AA0000
+    variable handleColor grey70
+    variable barColor grey30
+    variable textColor grey20
+
+    grid [button $w.dismiss -text Dismiss -command "destroy $w"] -row 2 -column 0 -pady 10
+    grid [button $w.code -text "See Code" -command "showCode $w"] -row 2 -column 1 -pady 10
+
+
+    grid [text $w.text -relief sunken -borderwidth 2 -setgrid true -height 3] \
+	-row 0 -column 0 -columnspan 2 -sticky ew
+
+    $w.text insert 0.0 {
+	6 examples of curves containing control points are displayed 
+	with the list of control points written just below.
+	You can move the handles to modify the bezier curves
+    }
 
-#zinc $w.zinc -width 700 -height 650 -font 9x15 -borderwidth 0 -tile $texture
-zinc $w.zinc -width 700 -height 650 -font 9x15 -borderwidth 0 -backcolor #898A8F
-pack $w.zinc
-
-
-set group [$w.zinc add group 1]
-
-$w.zinc add text $group -position {50 20} -anchor w -color $textColor \
-    -text {Examples of curve items using cubic bezier control points}
-
-## Please note: much of the items below could be computed
-$w.zinc add text $group -anchor w -position {25 270} -tags bezier1 -color $textColor -width 270
-$w.zinc add curve $group {100 200 100 100} -tags {line1 l1-2} \
-    -linecolor $barColor -filled 0 -linewidth 2
-$w.zinc add curve $group {400 100 400 200} -tags {line1 l3-4} \
-    -linecolor $barColor -filled 0 -linewidth 2
-$w.zinc add curve $group {{100 200} {100 100 c} {400 100 c} {400 200}} \
-    -tags bezier1 -closed 0 -linecolor $splineColor -linewidth 5
-$w.zinc add arc $group {90 190 110 210} -tags {handle1 p1} -filled 1 \
-    -fillcolor \#BBBBBB
-$w.zinc add arc $group {90 90 110 110} -tags {handle1 p2} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor -filled 1
-$w.zinc add arc $group {390 90 410 110} -tags {handle1 p3} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor -filled 1
-$w.zinc add arc $group {390 190 410 210} -tags {handle1 p4} -filled 1 \
-    -fillcolor \#BBBBBB
-
-$w.zinc add text $group -anchor w -position {570 270} -tags bezier2 -color $textColor -width 270
-$w.zinc add curve $group {600 200 675 100} -tags {line2 l1-2} \
-    -linecolor $barColor -linewidth 2
-$w.zinc add curve $group {975 100 900 200} -tags {line2 l3-4} \
-    -linecolor $barColor -linewidth 2
-$w.zinc add curve $group {{600 200} {675 100 c} {975 100 c} {900 200}} \
-    -tags bezier2 -closed 0 -linecolor $splineColor -linewidth 5
-$w.zinc add arc $group {590 190 610 210} -tags {handle2 p1} -filled 1 \
-    -fillcolor $handleColor
-$w.zinc add arc $group {665 90 685 110} -tags {handle2 p2} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor
-$w.zinc add arc $group {965 90 985 110} -tags {handle2 p3} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor
-$w.zinc add arc $group {890 190 910 210} -tags {handle2 p4} -filled 1 \
-    -fillcolor $handleColor
-
-$w.zinc add text $group -anchor w -position {25 570} -tags bezier3 -color $textColor -width 270
-$w.zinc add curve $group {100 500 25 400} -tags {line3 l1-2} \
-    -linecolor $barColor -linewidth 2
-$w.zinc add curve $group {475 400 400 500} -tags {line3 l3-4} \
-    -linecolor $barColor -linewidth 2
-$w.zinc add curve $group {{100 500} {25 400 c} {475 400 c} {400 500}} \
-    -tags {bezier3} -closed 0 -linecolor $splineColor -linewidth 5
-$w.zinc add arc $group {90 490 110 510} -tags {handle3 p1} -filled 1 \
-    -fillcolor $handleColor
-$w.zinc add arc $group {15 390 35 410} -tags {handle3 p2} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor 
-$w.zinc add arc $group {465 390 485 410} -tags {handle3 p3} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor 
-$w.zinc add arc $group {390 490 410 510} -tags {handle3 p4} -filled 1 \
-    -fillcolor $handleColor
-
-$w.zinc add text $group -anchor w -position {570 570} -tags bezier4 -color $textColor -width 270
-$w.zinc add curve $group {600 500 600 350} -tags {line4 l1-2} \
-    -linecolor $barColor -linewidth 2
-$w.zinc add curve $group {900 650 900 500} -tags {line4 l3-4} \
-    -linecolor $barColor -linewidth 2
-$w.zinc add curve $group {{600 500} {600 350 c} {900 650 c} {900 500}} \
-    -tags {bezier4} -closed 0 -linecolor $splineColor -linewidth 5
-$w.zinc add arc $group {590 490 610 510} -tags {handle4 p1} -filled 1 \
-    -fillcolor $handleColor
-$w.zinc add arc $group {590 340 610 360} -tags {handle4 p2} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor
-$w.zinc add arc $group {890 640 910 660} -tags {handle4 p3} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor
-$w.zinc add arc $group {890 490 910 510} -tags {handle4 p4} -filled 1 \
-    -fillcolor $handleColor
-
-$w.zinc add text $group -anchor w -position {25 870} -tags bezier5 -color $textColor -width 270
-$w.zinc add curve $group {100 800 175 700} -tags {line5 l1-2} \
-    -linecolor $barColor -filled 0 -linewidth 2
-$w.zinc add curve $group {325 700 400 800} -tags {line5 l3-4} \
-    -linecolor $barColor -filled 0 -linewidth 2
-$w.zinc add curve $group {{100 800} {175 700 c} {325 700 c} {400 800}} \
-    -tags {bezier5} -closed 0 -linecolor $splineColor -linewidth 5
-$w.zinc add arc $group {90 790 110 810} -tags {handle5 p1} -filled 1 \
-    -fillcolor $handleColor
-$w.zinc add arc $group {165 690 185 710} -tags {handle5 p2} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor -filled 1
-$w.zinc add arc $group {315 690 335 710} -tags {handle5 p3} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor -filled 1
-$w.zinc add arc $group {390 790 410 810} -tags {handle5 p4} -filled 1 \
-    -fillcolor $handleColor
-
-$w.zinc add text $group -anchor w -position {570 970} -tags bezier6 -color $textColor -width 280
-$w.zinc add curve $group {600 800 625 700} -tags {line6 l1-2} \
-    -linecolor $barColor -linewidth 2
-$w.zinc add curve $group {725 700 750 800} -tags {line6 l3-4} \
-    -linecolor $barColor -linewidth 2
-$w.zinc add curve $group {750 800 775 900} -tags {line6 l4-5} \
-    -linecolor $barColor -linewidth 2
-$w.zinc add curve $group {875 900 900 800} -tags {line6 l6-7} \
-    -linecolor $barColor -linewidth 2
-$w.zinc add curve $group {
-    {600 800} {625 700 c} {725 700 c} {750 800}
-    {775 900 c} {875 900 c} {900 800}
-} -tags {bezier6} -filled 0 -closed 0 -linecolor $splineColor -linewidth 5
-$w.zinc add arc $group {590 790 610 810} -tags {handle6 p1} -filled 1 \
-    -fillcolor $handleColor
-$w.zinc add arc $group {615 690 635 710} -tags {handle6 p2} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor
-$w.zinc add arc $group {715 690 735 710} -tags {handle6 p3} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor
-$w.zinc add arc $group {740 790 760 810} -tags {handle6 p4} -filled 1 \
-    -linecolor blue -fillcolor blue -linewidth 2
-$w.zinc add arc $group {766 891 784 909} -tags {handle6 p5} -filled 1 \
-    -fillcolor $handleColor
-$w.zinc add arc $group {865 890 885 910} -tags {handle6 p6} -filled 1 \
-    -linewidth 0 -fillcolor $handleColor
-$w.zinc add arc $group {890 790 910 810} -tags {handle6 p7} -filled 1 \
-    -fillcolor $handleColor
-
-
-$w.zinc scale $group 0.6 0.6
-
-## Set the text of the text item with a tag "tag"
-## to a human-readable form of the coords of the
-## corresponding curve with the same tag "tag"
-proc setText {tag} {
-    global w
-    set textItem  [$w.zinc find withtype text $tag]
-    set curveItem [$w.zinc find withtype curve $tag]
-    set coords [$w.zinc coords $curveItem]
-    set count 0
-    $w.zinc itemconfigure $textItem -text $coords
-}
+    #zinc $w.zinc -width 700 -height 650 -font 9x15 -borderwidth 0 -tile $texture
+    grid [zinc $w.zinc -width 700 -height 650 -font 9x15 -borderwidth 0 \
+	      -backcolor \#898A8F] -row 1 -column 0 -columnspan 2 -sticky news
+    grid columnconfigure $w 0 -weight 1
+    grid columnconfigure $w 1 -weight 1
+    grid rowconfigure $w 1 -weight 2
+
+    variable group [$w.zinc add group 1]
+
+    $w.zinc add text $group -position {50 20} -anchor w -color $textColor \
+	-text {Examples of curve items using cubic bezier control points}
+
+    ## Please note: much of the items below could be computed
+    $w.zinc add text $group -anchor w -position {25 270} -tags bezier1 -color $textColor -width 270
+    $w.zinc add curve $group {100 200 100 100} -tags {line1 l1-2} \
+	-linecolor $barColor -filled 0 -linewidth 2
+    $w.zinc add curve $group {400 100 400 200} -tags {line1 l3-4} \
+	-linecolor $barColor -filled 0 -linewidth 2
+    $w.zinc add curve $group {{100 200} {100 100 c} {400 100 c} {400 200}} \
+	-tags bezier1 -closed 0 -linecolor $splineColor -linewidth 5
+    $w.zinc add arc $group {90 190 110 210} -tags {handle1 p1} -filled 1 \
+	-fillcolor \#BBBBBB
+    $w.zinc add arc $group {90 90 110 110} -tags {handle1 p2} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor -filled 1
+    $w.zinc add arc $group {390 90 410 110} -tags {handle1 p3} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor -filled 1
+    $w.zinc add arc $group {390 190 410 210} -tags {handle1 p4} -filled 1 \
+	-fillcolor \#BBBBBB
+
+    $w.zinc add text $group -anchor w -position {570 270} -tags bezier2 -color $textColor -width 270
+    $w.zinc add curve $group {600 200 675 100} -tags {line2 l1-2} \
+	-linecolor $barColor -linewidth 2
+    $w.zinc add curve $group {975 100 900 200} -tags {line2 l3-4} \
+	-linecolor $barColor -linewidth 2
+    $w.zinc add curve $group {{600 200} {675 100 c} {975 100 c} {900 200}} \
+	-tags bezier2 -closed 0 -linecolor $splineColor -linewidth 5
+    $w.zinc add arc $group {590 190 610 210} -tags {handle2 p1} -filled 1 \
+	-fillcolor $handleColor
+    $w.zinc add arc $group {665 90 685 110} -tags {handle2 p2} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor
+    $w.zinc add arc $group {965 90 985 110} -tags {handle2 p3} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor
+    $w.zinc add arc $group {890 190 910 210} -tags {handle2 p4} -filled 1 \
+	-fillcolor $handleColor
+
+    $w.zinc add text $group -anchor w -position {25 570} -tags bezier3 -color $textColor -width 270
+    $w.zinc add curve $group {100 500 25 400} -tags {line3 l1-2} \
+	-linecolor $barColor -linewidth 2
+    $w.zinc add curve $group {475 400 400 500} -tags {line3 l3-4} \
+	-linecolor $barColor -linewidth 2
+    $w.zinc add curve $group {{100 500} {25 400 c} {475 400 c} {400 500}} \
+	-tags {bezier3} -closed 0 -linecolor $splineColor -linewidth 5
+    $w.zinc add arc $group {90 490 110 510} -tags {handle3 p1} -filled 1 \
+	-fillcolor $handleColor
+    $w.zinc add arc $group {15 390 35 410} -tags {handle3 p2} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor 
+    $w.zinc add arc $group {465 390 485 410} -tags {handle3 p3} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor 
+    $w.zinc add arc $group {390 490 410 510} -tags {handle3 p4} -filled 1 \
+	-fillcolor $handleColor
+
+    $w.zinc add text $group -anchor w -position {570 570} -tags bezier4 -color $textColor -width 270
+    $w.zinc add curve $group {600 500 600 350} -tags {line4 l1-2} \
+	-linecolor $barColor -linewidth 2
+    $w.zinc add curve $group {900 650 900 500} -tags {line4 l3-4} \
+	-linecolor $barColor -linewidth 2
+    $w.zinc add curve $group {{600 500} {600 350 c} {900 650 c} {900 500}} \
+	-tags {bezier4} -closed 0 -linecolor $splineColor -linewidth 5
+    $w.zinc add arc $group {590 490 610 510} -tags {handle4 p1} -filled 1 \
+	-fillcolor $handleColor
+    $w.zinc add arc $group {590 340 610 360} -tags {handle4 p2} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor
+    $w.zinc add arc $group {890 640 910 660} -tags {handle4 p3} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor
+    $w.zinc add arc $group {890 490 910 510} -tags {handle4 p4} -filled 1 \
+	-fillcolor $handleColor
+
+    $w.zinc add text $group -anchor w -position {25 870} -tags bezier5 -color $textColor -width 270
+    $w.zinc add curve $group {100 800 175 700} -tags {line5 l1-2} \
+	-linecolor $barColor -filled 0 -linewidth 2
+    $w.zinc add curve $group {325 700 400 800} -tags {line5 l3-4} \
+	-linecolor $barColor -filled 0 -linewidth 2
+    $w.zinc add curve $group {{100 800} {175 700 c} {325 700 c} {400 800}} \
+	-tags {bezier5} -closed 0 -linecolor $splineColor -linewidth 5
+    $w.zinc add arc $group {90 790 110 810} -tags {handle5 p1} -filled 1 \
+	-fillcolor $handleColor
+    $w.zinc add arc $group {165 690 185 710} -tags {handle5 p2} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor -filled 1
+    $w.zinc add arc $group {315 690 335 710} -tags {handle5 p3} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor -filled 1
+    $w.zinc add arc $group {390 790 410 810} -tags {handle5 p4} -filled 1 \
+	-fillcolor $handleColor
+
+    $w.zinc add text $group -anchor w -position {570 970} -tags bezier6 -color $textColor -width 280
+    $w.zinc add curve $group {600 800 625 700} -tags {line6 l1-2} \
+	-linecolor $barColor -linewidth 2
+    $w.zinc add curve $group {725 700 750 800} -tags {line6 l3-4} \
+	-linecolor $barColor -linewidth 2
+    $w.zinc add curve $group {750 800 775 900} -tags {line6 l4-5} \
+	-linecolor $barColor -linewidth 2
+    $w.zinc add curve $group {875 900 900 800} -tags {line6 l6-7} \
+	-linecolor $barColor -linewidth 2
+    $w.zinc add curve $group {
+	{600 800} {625 700 c} {725 700 c} {750 800}
+	{775 900 c} {875 900 c} {900 800}
+    } -tags {bezier6} -filled 0 -closed 0 -linecolor $splineColor -linewidth 5
+    $w.zinc add arc $group {590 790 610 810} -tags {handle6 p1} -filled 1 \
+	-fillcolor $handleColor
+    $w.zinc add arc $group {615 690 635 710} -tags {handle6 p2} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor
+    $w.zinc add arc $group {715 690 735 710} -tags {handle6 p3} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor
+    $w.zinc add arc $group {740 790 760 810} -tags {handle6 p4} -filled 1 \
+	-linecolor blue -fillcolor blue -linewidth 2
+    $w.zinc add arc $group {766 891 784 909} -tags {handle6 p5} -filled 1 \
+	-fillcolor $handleColor
+    $w.zinc add arc $group {865 890 885 910} -tags {handle6 p6} -filled 1 \
+	-linewidth 0 -fillcolor $handleColor
+    $w.zinc add arc $group {890 790 910 810} -tags {handle6 p7} -filled 1 \
+	-fillcolor $handleColor
+
+
+    $w.zinc scale $group 0.6 0.6
+
+    ## Set the text of the text item with a tag "tag"
+    ## to a human-readable form of the coords of the
+    ## corresponding curve with the same tag "tag"
+    proc setText {tag} {
+	variable w
+	set textItem  [$w.zinc find withtype text $tag]
+	set curveItem [$w.zinc find withtype curve $tag]
+	set coords [$w.zinc coords $curveItem]
+	set count 0
+	$w.zinc itemconfigure $textItem -text $coords
+    }
 
-foreach bezierCount {1 2 3 4 5 6} {
-    setText "bezier$bezierCount"
-    set curveItem [$w.zinc find withtype curve "bezier$bezierCount"]
-    set coords [$w.zinc coords $curveItem]
-    #puts "$bezierCount : $curveItem : $coords"
-    $w.zinc bind "handle$bezierCount" <1> {itemStartDrag %x %y}
-    $w.zinc bind "handle$bezierCount" <B1-Motion> {itemDrag %x %y}
-    #$w.zinc bind "handle$bezierCount" "<ButtonPress-1>" {\&press \&motion}
-    #$w.zinc bind "handle$bezierCount" "<ButtonRelease-1>" {\&release}
-}
+    foreach bezierCount {1 2 3 4 5 6} {
+	setText "bezier$bezierCount"
+	set curveItem [$w.zinc find withtype curve "bezier$bezierCount"]
+	set coords [$w.zinc coords $curveItem]
+	#puts "$bezierCount : $curveItem : $coords"
+	$w.zinc bind "handle$bezierCount" <1> {::curveBezier::itemStartDrag %x %y}
+	$w.zinc bind "handle$bezierCount" <B1-Motion> {::curveBezier::itemDrag %x %y}
+	#$w.zinc bind "handle$bezierCount" "<ButtonPress-1>" {\&press \&motion}
+	#$w.zinc bind "handle$bezierCount" "<ButtonRelease-1>" {\&release}
+    }
 
 
 
 
-##### bindings for moving the handles
-set item ""
-set bezierNum "" 
-set ptNum ""
+    ##### bindings for moving the handles
+    variable item ""
+    variable bezierNum "" 
+    variable ptNum ""
 
-set x_orig ""
-set y_orig ""
+    variable xOrig 0
+    variable yOrig 0
 
-proc itemStartDrag {x y} {
-    global w
-    global x_orig y_orig
-    global bezierNum ptNum
-    global item
-    set x_orig $x
-    set y_orig $y
-    set item [$w.zinc find withtag current]
-    
-    foreach val [$w.zinc gettags $item] {
-	regexp {([a-z]+)(\d)} $val "" name num
-	if {$name=="handle"} {set bezierNum $num}
-	if {$name=="p"} {set ptNum $num}
+    proc itemStartDrag {x y} {
+	variable w
+	variable xOrig
+	variable yOrig
+	variable bezierNum
+	variable ptNum
+	variable item
+
+	set xOrig $x
+	set yOrig $y
+	set item [$w.zinc find withtag current]
+	
+	foreach val [$w.zinc gettags $item] {
+	    regexp {([a-z]+)(\d)} $val "" name num
+	    if {$name=="handle"} {set bezierNum $num}
+	    if {$name=="p"} {set ptNum $num}
+	}
+	#puts "bezierNum=$bezierNum ptNum=$ptNum"
     }
-    #puts "bezierNum=$bezierNum ptNum=$ptNum"
-}
 
-# Callback for moving an item
-proc itemDrag {x y} {
-    global x_orig y_orig
-    global w
-    global item
-    $w.zinc transform $item "[expr $x-$x_orig] [expr $y-$y_orig]"
-    moveHandle [expr $x-$x_orig] [expr $y-$y_orig]
-    set x_orig $x;
-    set y_orig $y;
-}
+    # Callback for moving an item
+    proc itemDrag {x y} {
+	variable xOrig
+	variable yOrig
+	variable w
+	variable item
+
+	$w.zinc transform $item "[expr $x - $xOrig] [expr $y - $yOrig]"
+	moveHandle [expr $x - $xOrig] [expr $y - $yOrig]
+	set xOrig $x
+	set yOrig $y
+    }
 
 
-proc moveHandle {dx dy} {
-    global w
-    global bezierNum
-    global ptNum
-    global item
-    set pt1 [lindex [$w.zinc coords $item] 0]
-    set pt2 [lindex [$w.zinc coords $item] 1]
-    
-    ## modifying the handle coords
-    $w.zinc coords $item "[expr [lindex $pt1 0]+$dx] [expr [lindex $pt1 1]+$dy] [expr [lindex $pt2 0]+$dx] [expr [lindex $pt2 1]+$dy]"
-    set prevPtNum [expr $ptNum-1]
-    
-    # there should only be one such item!
-    set lineA [$w.zinc find withtag "line$bezierNum && l$prevPtNum-$ptNum"]
-    if {$lineA!=""} {
-	set x [lindex [$w.zinc coords $lineA 0 1] 0]
-	set y [lindex [$w.zinc coords $lineA 0 1] 1]
-	$w.zinc coords $lineA 0 1 "[expr $x+$dx] [expr $y+$dy]"
-    }
-    
-    set nextPtNum [expr $ptNum+1]
-    # there should only be one such item:
-    set lineB [$w.zinc find withtag "line$bezierNum && l$ptNum-$nextPtNum"]
-    if {$lineB!=""} {
-	set x [lindex [$w.zinc coords $lineB 0 0] 0]
-	set y [lindex [$w.zinc coords $lineB 0 0] 1]
-	$w.zinc coords $lineB 0 0 "[expr $x+$dx] [expr $y+$dy]"
+    proc moveHandle {dx dy} {
+	variable w
+	variable bezierNum
+	variable ptNum
+	variable item
+
+	set pt1 [lindex [$w.zinc coords $item] 0]
+	set pt2 [lindex [$w.zinc coords $item] 1]
+	
+	## modifying the handle coords
+	$w.zinc coords $item "[expr [lindex $pt1 0]+$dx] [expr [lindex $pt1 1]+$dy] [expr [lindex $pt2 0]+$dx] [expr [lindex $pt2 1]+$dy]"
+	set prevPtNum [expr $ptNum-1]
+	
+	# there should only be one such item!
+	set lineA [$w.zinc find withtag "line$bezierNum && l$prevPtNum-$ptNum"]
+	if {$lineA!=""} {
+	    set x [lindex [$w.zinc coords $lineA 0 1] 0]
+	    set y [lindex [$w.zinc coords $lineA 0 1] 1]
+	    $w.zinc coords $lineA 0 1 "[expr $x+$dx] [expr $y+$dy]"
+	}
+	
+	set nextPtNum [expr $ptNum+1]
+	# there should only be one such item:
+	set lineB [$w.zinc find withtag "line$bezierNum && l$ptNum-$nextPtNum"]
+	if {$lineB!=""} {
+	    set x [lindex [$w.zinc coords $lineB 0 0] 0]
+	    set y [lindex [$w.zinc coords $lineB 0 0] 1]
+	    $w.zinc coords $lineB 0 0 "[expr $x+$dx] [expr $y+$dy]"
+	}
+	set tab [$w.zinc coords "bezier$bezierNum" 0 [expr $ptNum-1]]
+	set x [lindex $tab 0]
+	set y [lindex $tab 1]
+	set control [lindex $tab 2]
+	$w.zinc coords "bezier$bezierNum" 0 [expr $ptNum-1] "[expr $x+$dx] [expr $y+$dy] $control"
+	setText "bezier$bezierNum"  
     }
-    set tab [$w.zinc coords "bezier$bezierNum" 0 [expr $ptNum-1]]
-    set x [lindex $tab 0]
-    set y [lindex $tab 1]
-    set control [lindex $tab 2]
-    $w.zinc coords "bezier$bezierNum" 0 [expr $ptNum-1] "[expr $x+$dx] [expr $y+$dy] $control"
-    setText "bezier$bezierNum"  
 }