can't read "filename": no such variable
    while executing
"string length $filename"
    invoked from within
"if {[string length $filename]} {
## Ensure that the window is on top of everything else, so as not to get
## white ranges in the image, due to overlap..."
    (in namespace eval "::request" script line 1)
    invoked from within
"namespace eval ::request $script"
    ("::try" body line 12)
OUTPUT BUFFER:
if {[string length $filename]} {
## Ensure that the window is on top of everything else, so as not to get
## white ranges in the image, due to overlapped portions of the window
with
## other windows...
raise [winfo toplevel $canvas]
update
set border [expr {[$canvas cget -borderwidth] +
[$canvas cget -highlightthickness]}]
set view_height [expr {[winfo height $canvas]-2*$border}]
set view_width [expr {[winfo width $canvas]-2*$border}]
foreach {x1 y1 x2 y2} [$canvas bbox all] {break}
set x1 [expr {int($x1-10)}]
set y1 [expr {int($y1-10)}]
set x2 [expr {int($x2+10)}]
set y2 [expr {int($y2+10)}]
set width [expr {$x2-$x1}]
set height [expr {$y2-$y1}]
namespace eval ::MainWindow::images {}
image create photo ::MainWindow::images::windowImage \
-height $height -width $width
## Arrange the scrollregion of the canvas to get the whole window
visible,
## so as to grab it into an image...
set scrollregion [$canvas cget -scrollregion]
set xscrollcommand [$canvas cget -xscrollcommand]
set yscrollcommand [$canvas cget -yscrollcommand]
$canvas configure -xscrollcommand {}
$canvas configure -yscrollcommand {}
set grabbed_x $x1
set grabbed_y $y1
set image_x 0
set image_y 0
while {$grabbed_y < $y2} {
while {$grabbed_x < $x2} {
$canvas configure -scrollregion [list $grabbed_x $grabbed_y \
[expr {$grabbed_x + $view_width}] [expr {$grabbed_y +
$view_height}]]
update
## Take a screenshot of the visible canvas part...
image create photo ::MainWindow::images::tmp_image \
-format window -data $canvas
## Copy the screenshot to the target image...
::MainWindow::images::windowImage copy
::MainWindow::images::tmp_image \
-to $image_x $image_y -from $border $border
incr grabbed_x $view_width
incr image_x $view_width
}
set grabbed_x $x1
set image_x 0
incr grabbed_y $view_height
incr image_y $view_height
}
$canvas configure -scrollregion $scrollregion
$canvas configure -xscrollcommand $xscrollcommand
$canvas configure -yscrollcommand $yscrollcommand
switch -glob -- [string tolower $filename] {
*.png {set format png}
*.jpg - *.jpeg {set format jpeg}
*.bmp {set format bmp}
default {set format bmp}
}
::MainWindow::images::windowImage write $filename -format $format
image delete ::MainWindow::images::windowImage \
::MainWindow::images::tmp_image
}