Richard Suchenwirth 2004-09-28 - Here's code for photo image rotation by +90 or -90 degrees only, but it runs reasonably fast:
proc imgrot90 {img {clockwise 0}} {
set w [image width $img]
set h [image height $img]
set matrix [string repeat "{[string repeat {0 } $h]} " $w]
if $clockwise {
set x0 0; set y [expr {$h-1}]; set dx 1; set dy -1
} else {
set x0 [expr {$w-1}]; set y 0; set dx -1; set dy 1
}
foreach row [$img data] {
set x $x0
foreach pixel $row {
lset matrix $x $y $pixel
incr x $dx
}
incr y $dy
}
set im2 [image create photo -width $h -height $w]
$im2 put $matrix
set im2
}For fast arbitrary rotation (and scaling) see: Enhanced photo image copy command
Arts and crafts of Tcl-Tk programming