ulis, 2003-06-23 A widget can be serialized by saving its state in a string that can be used to restore later the state of the widget.
A serialized widget can be cloned or made persistent.
The procs (clone, save, restore, dump)
# ==============================
#
# clone a canvas widget
#
# ==============================
# ----------
# canvas:clone proc
# ----------
# parm1: canvas widget
# parm2: clone canvas widget
# ----------
proc canvas:clone {canvas clone} { canvas:restore $clone [canvas:save $canvas] }
# ----------
# options proc
#
# return non empty options
# ----------
# parm: options list
# ----------
# return: non empty options list
# ----------
proc options {options} \
{
set res {}
foreach option $options \
{
set key [lindex $option 0]
set value [lindex $option 4]
# due to bugs in canvas widget, must save all options,
# even those with empty values:
# if {$value != ""} { lappend res [list $key $value] }
if {[llength $option] == 5} {lappend res [list $key $value]}
}
return $res
}
# ----------
# canvas:save proc
#
# serialize a canvas widget
# ----------
# parm1: canvas widget path
# ----------
# return: serialized widget
# ----------
proc canvas:save {w} \
{
# canvas name
lappend save $w
# canvas option
lappend save [options [$w configure]]
# canvas focus
lappend save [$w focus]
# canvas items
foreach id [$w find all] \
{
set item {}
# type & id
set type [$w type $id]
lappend item [list $type $id]
# coords
lappend item [$w coords $id]
# tags
set tags [$w gettags $id]
lappend item $tags
# binds
set binds {}
# id binds
set events [$w bind $id]
foreach event $events \
{ lappend binds [list $id $event [$w bind $id $event]] }
# tags binds
foreach tag $tags \
{
set events [$w bind $tag]
foreach event $events \
{ lappend binds [list $tag $event [$w bind $tag $event]] }
}
lappend item $binds
# options
lappend item [options [$w itemconfigure $id]]
# type specifics
set specifics {}
switch $type \
{
arc {}
bitmap {}
image \
{
# image name
set iname [$w itemcget $id -image]
lappend specifics $iname
# image type
lappend specifics [image type $iname]
# image options
lappend specifics [options [$iname configure]]
}
line {}
oval {}
polygon {}
rectangle {}
text \
{
foreach index {insert sel.first sel.last} \
{
# text indexes
catch \
{ lappend specifics [$w index $id $index] }
}
}
window \
{
# window name
set wname [$w itemcget $id -window]
lappend specifics $wname
# window type
lappend specifics [string tolower [winfo class $wname]]
# window options
lappend specifics [options [$wname configure]]
}
}
lappend item $specifics
lappend save $item
}
# return serialized canvas
return $save
}
# ----------
# canvas:restore proc
#
# restore a serialized canvas widget
# ----------
# parm1: canvas widget path
# parm2: serialized widget to restore
# ----------
proc canvas:restore {w save} \
{
# create canvas options
eval canvas $w [join [lindex $save 1]]
# items
foreach item [lrange $save 3 end] \
{
foreach {typeid coords tags binds options specifics} $item \
{
# get type
set type [lindex $typeid 0]
# create bitmap or window
switch $type \
{
image \
{
foreach {iname itype ioptions} $specifics break
if {![image inuse $iname]} \
{ eval image create $itype $iname [join $ioptions] }
}
window \
{
foreach {wname wtype woptions} $specifics break
if {![winfo exists $wname]} \
{ eval $wtype $wname [join $woptions] }
raise $wname
}
}
# create item
set id [eval $w create $type $coords -tags "{$tags}" [join $options]]
# item bindings
foreach bind $binds \
{
foreach {id event script} $bind { $w bind $id $event $script }
}
# item specifics
if {$specifics != ""} \
{
switch $type \
{
text \
{
foreach {insert sel.first sel.last} $specifics break
$w icursor $id $insert
if {${sel.first} != ""} \
{
$w select from $id ${sel.first}
$w select to $id ${sel.last}
}
}
}
}
}
}
# focused item
set focus [lindex $save 2]
if {$focus != ""} \
{
$w focus [lindex $save 2]
focus -force $w
}
# return path
return $w
}
# ----------
# canvas:dump proc
#
# dump a canvas widget
# ----------
# parm: canvas widget path
# ----------
# return: widget dump
# ----------
proc canvas:dump {w} \
{
set w [canvas:save $w]
# canvas name
lappend res [lindex $w 0]
# canvas options
foreach option [lindex $w 1] { lappend res [join $option \t] }
# focused item
lappend res [join [lindex $w 2] \t]
# items
foreach item [lrange $w 3 end] \
{
foreach {type coords tags binds options specifics} $item \
{
# item type
lappend res [join $type \t]
# item coords
lappend res \tcoords\t$coords
# item tags
lappend res \ttags\t$tags
# item bindings
lappend res \tbinds
foreach bind $binds { lappend res \t\t$bind }
# item options
lappend res \toptions
foreach option $options \
{
set key [lindex $option 0]
set value [lindex $option 1]
lappend res \t\t$key\t$value
}
# item specifics
if {$specifics != ""} \
{
lappend res \tspecifics
foreach specific $specifics \
{
if {[llength $specific] == 1} { lappend res \t\t$specific } \
else { foreach token $specific { lappend res \t\t$token } }
}
}
}
}
# return dump
return [join $res \n]
}
The demo
# =========
# demo
# =========
# create initial canvas
pack [frame .f]
set c .f.c
pack [canvas $c]
$c create arc 10 10 100 100 -extent 60 -start 30 -style pieslice -tag arc
$c bind arc <1> { arc_script }
$c create bitmap 10 30 -bitmap question
image create photo img1 -data \
{
R0lGODdhCQAJAIAAAASCBPz+/CwAAAAACQAJAAACEYwPp5Aa3BBcMJrqHsua
P1MAADs=
}
image create photo img2 -file left.gif
$c create image 40 125 -image img1 -tag {img _img_}
set id [$c create image 60 125 -image img2 -tag {img _img_}]
$c bind img <ButtonPress> { img_script_button }
$c bind img <KeyPress> { img_script_key }
$c bind _img_ <KeyPress> { _img_script_key }
$c bind $id <KeyPress> { img_script_key_id }
set data "#define v_width 8\n#define v_height 4"
append data { static unsigned char v_bits[] = { 0x18, 0x3c, 0x7e, 0xff }; }
image create bitmap bmp -data $data
$c create image 40 70 -image bmp
$c create line 10 10 50 50 100 10 150 50
$c create oval 10 10 100 100
$c create polygon 10 100 50 50 100 100 150 50
$c create rectangle 10 10 150 150
$c create text 120 120 -text "test" -font {Courier 16}
label .f.l -text Label
$c create window 50 50 -window .f.l
# clone canvas
set c2 .f.c2
pack [canvas:clone $c $c2]
update
# after waiting,
after 5000
# save old canvas
set save [canvas:save $c2]
# delete it
destroy $c $c2
# restore it
pack [canvas:restore $c $save]
dzach Cloning is nice. What would be even better, is the ability to view an existing canvas but from a different window with a different origin, without any duplication of canvas items. For mapping (but not only) applications, this would be ideal. I am probably a little off topic, I admit.
gold Here's some optional TCL code for viewing and saving the canvas string notation as a file in the console window; works with etcl on Windows XP. Load this code after "set save ... " as shown. I think this might be useful for saving canvases from Refrigerator Pinyin Poetry and UML play. I usually set a random number so I can tell saved canvases apart.
#works with etcl on Windows XP,27Apr2007,gold
set save [canvas:save $c2]
proc conprint {texttext} {
console show
console eval {.console configure -font {Courier 10}}
set tile [expr {int(rand()*1000000000.)}]
puts " saved canvas number is $tile ******* $texttext "
}
conprint $save