image create photo img1 -file left.gif [image create photo img2] put [img1 data]
save and restore procs
# ==============================
#
# serializing a photo
#
# ==============================
# ---------------------
# options proc
#
# return a list of non empty options
# ---------------------
# parm: image name
# ---------------------
# return: list of non empty options
# ---------------------
proc options {name} \
{
set res {}
foreach option [$name configure] \
{
set key [lindex $option 0]
set value [lindex $option 3]
if {$value != ""} { lappend res [list $key $value] }
}
return $res
}
# ---------------------
# photo:save proc
#
# return a serialized photo
# ---------------------
# parm1: image name
# parm2: optional option -getdata
# -getdata: force to save the data
# ---------------------
# return: serialized photo
# ---------------------
# use:
# photo:save name ?-getdata?
# ---------------------
proc photo:save {name args} \
{
# save name
set res [list $name]
# save options
set options [options $name]
lappend res $options
# get data flag
switch -glob -- $args \
{
-get* { set getdata 1 }
"" \
{
set n [lsearch $options -file]
set getdata [expr {$n == -1 ? 1 : 0}]
}
default { error "unknown option \"$args\"" }
}
# save data
if {$getdata} { lappend res [$name data] }
# return string
return $res
}
# ---------------------
# photo:restore
#
# create a photo from a serialized one
# ---------------------
# parm1: serialized photo
# parm2: optional name option
# -noname: don't restore the name
# non empty: set the name with parm2
# ---------------------
# use:
# photo:restore image_string ?-noname|name?
# ---------------------
proc photo:restore {image args} \
{
# init cmd
set cmd "image create photo"
# set name
switch -glob -- $args \
{
-non* { }
"" { append cmd " [lindex $image 0]" }
default { append cmd " $args" }
}
# set options
foreach option [lindex $image 1] { append cmd " $option" }
# create photo
set img [eval $cmd]
# put data
if {[llength $image] > 2} { $img put [lindex $image 2] }
}The demo
# ==============================
#
# demo
#
# ==============================
# create a photo from a string
image create photo _img1_ -data \
{
R0lGODdhCQAJAIAAAASCBPz+/CwAAAAACQAJAAACEYwPp5Aa3BBcMJrqHsua
P1MAADs=
}
# create a photo from a file
_img1_ write photo.gif
image create photo _img2_ -file photo.gif
# save photos
set saved1 [photo:save _img1_]
set saved2 [photo:save _img2_]
# force to save data
set saved3 [photo:save _img2_ -getdata]
# delete photos
image delete _img1_ _img2_
# restore photos
photo:restore $saved1
photo:restore $saved2
photo:restore $saved3 _img3_
# show them
pack [canvas .c]
.c create image 10 10 -image _img1_
.c create image 30 10 -image _img2_
.c create image 50 10 -image _img3_