wdb The procedure canvasdump provides an easy way to save and restore contents of a canvas. Simplifies copying of canvas contents.
Example of storing:
% set canvasContents [canvasdump .c]
canvas {
list\
[$canvas create rectangle {10.0 10.0 100.0 100.0} -fill yellow -width 5.0]\
[$canvas create oval {50.0 50.0 150.0 150.0} -fill red -width 5.0]
}Restoring:
% toplevel .top
.top
% pack [canvas .top.c]
% apply $canvasContents .top.c
1 2
% # .top.c contains drawing of .c; result is list of IDs
Code:
proc canvasdump canvas {
set items ""
foreach item [$canvas find all] {
set cmd create
lappend cmd [$canvas type $item]
set coords {}
foreach x [$canvas coords $item] {
lappend coords [expr [format %f $x]]
}
lappend cmd $coords
foreach li [$canvas itemconfigure $item] {
lassign $li key - - def val
if {$def != $val} then {
if {$key eq "-image"} then {
set image [$canvas itemcget $item -image]
set file [$image cget -file]
append cmd " $key " [subst -nocommand {[image create photo -file "$file"]}]
} else {
append cmd " $key " [list $val]
}
}
}
lappend items " \[\$canvas $cmd\]"
}
set lines [join $items \\\n]\n
concat canvas "{\n list\\\n$lines}"
}
