CPU usage test

toplevel .t
canvas .t.can

set point_size 10
set zoom_out_factor 4
set square_size [expr {256 / $zoom_out_factor}]
set entry_width 80
set entry_height 20

for {set y 0}  {$y < $square_size} {incr y} {
    for {set x 0}  {$x < $square_size} {incr x} {
        .t.can create rect [expr {$x * $point_size}] [expr {$y * $point_size}] [expr {($x + 1) * $point_size}] [expr {($y + 1) * $point_size}] -outline black -fill white
    }
}

place .t.can -x 0 -y 0 -width [expr {$square_size * $point_size}] -height [expr {$square_size * $point_size}]

entry .t.l
place .t.l -width $entry_width -x [expr {($square_size * $point_size - $entry_width) / 2}] -height $entry_height -y [expr {($square_size * $point_size - $entry_height) / 2}]

wm geometry .t "[expr {$square_size * $point_size}]x[expr {$square_size * $point_size}]"