proc read_png_comments {file} {
set fh [open $file r]
fconfigure $fh -encoding binary -translation binary -eofchar {}
if {[read $fh 8] != "\x89PNG\r\n\x1a\n"} { close $fh; return }
set text {}
while {[set r [read $fh 8]] != ""} {
binary scan $r Ia4 len type
set r [read $fh $len]
if {[string length $r] != $len} { close $fh; return }
if {$type == "tEXt"} {
lappend text [split $r \x00]
}
seek $fh 4 current
}
close $fh
return $text
}Currently only supports uncompressed english comments. Todo list includes inflate support and unicode comments.
Returns a list where each element is a comment. Each comment is a list consisting of 2 elements: the human readable keyword, and the text data.
--AF