image create photo i -width 30 -height 30
arrowimage i up
pack [ttk::button .l -image i -style Toolbutton]

proc arrowimage { photoCmd dir {ipadx 0} {ipady 0} {clean 0} {foreground black} } {
    
    set width [$photoCmd cget -width]
    set height [$photoCmd cget -height]
    # w and h are max width and max height of arrow
    set w [expr {$width  - 2*$ipadx}]
    set h [expr {$height - 2*$ipady}]

    if { $w < 2 } {set w 2}
    if { $h < 2 } {set h 2}

    if { $clean > 0 } {
        # arrange for base to be odd
        if { [string equal $dir "top"] || [string equal $dir "bottom"] } {
            if { !($w % 2) } {
                incr w -1
            }
            if { $clean == 2 } {
                # arrange for h = (w+1)/2
                set h2 [expr {($w+1)/2}]
                if { $h2 > $h } {
                    set w [expr {2*$h-1}]
                } else {
                    set h $h2
                }
            }
        } else {
            if { !($h % 2) } {
                incr h -1
            }
            if { $clean == 2 } {
                # arrange for w = (h+1)/2
                set w2 [expr {($h+1)/2}]
                if { $w2 > $w } {
                    set h [expr {2*$w-1}]
                } else {
                    set w $w2
                }
            }
        }
    }

    set x0 [expr {($width-$w)/2}]
    set y0 [expr {($height-$h)/2}]
    set x1 [expr {$x0+$w-1}]
    set y1 [expr {$y0+$h-1}]
    # > Make the frame transparent and the inside with a square
    for {set y 0} {$y < $y0} {incr y} {
        for {set x 0} {$x < $height} {incr x} {
            $photoCmd transparency set $x $y 1
        }
    }
    for {set y [expr {$y1+1}]} {$y < $height} {incr y} {
        for {set x 0} {$x < $height} {incr x} {
            $photoCmd transparency set $x $y 1
        }
    }
    for {set y $y0} {$y <= $y1} {incr y} {
        for {set x 0} {$x < $x0} {incr x} {
            $photoCmd transparency set $x $y 1
        }
    }
    for {set y $y0} {$y <= $y1} {incr y} {
        for {set x [expr {$x1+1}]} {$x < $width} {incr x} {
            $photoCmd transparency set $x $y 1
        }
    }
    $photoCmd put $foreground -to $x0 $y0 [expr {$x1+1}] [expr {$y1+1}]
    # > Paint triangles as transparency
    switch $dir {
        top - bottom {
            set h0 $x0
            set h1 $x1
            set v0 $y0
            set v1 $y1
            # > On even size move right limit one to right
            set e1 [expr {($w % 2 == 0)?1:0}]
            set fHorX 1
        }
        default {
            set h0 $y0
            set h1 $y1
            set v0 $x0
            set v1 $x1
            # > On even size move right limit one to right
            set e1 [expr {($h % 2 == 0)?1:0}]
            set fHorX 0
        }
    }
    switch $dir {
        top - left {
            set corVert $v0
            set DCorVert 1
        }
        default {
            set corVert $v1
            set DCorVert -1
        }
    }
    set m [expr {($h0+$h1)/2}]
    set DHor [expr {$h1 - $m}]
    set DVert [expr {$v1 - $v0}]
    set d 0
    set r 0
    for {set vertLoop 0} {$vertLoop < $DVert} {incr vertLoop} {
        set limitHor [expr {$m - $d}]
        for {set horLoop 0} {$horLoop < $limitHor} {incr horLoop} {
            $photoCmd transparency set\
                    [expr {$fHorX?$horLoop:$corVert}]\
                    [expr {$fHorX?$corVert:$horLoop}] 1
        }
        set limitHor [expr {$m + $d + 1 + $e1}]
        for {set horLoop $limitHor} {$horLoop <= $h1} {incr horLoop} {
            $photoCmd transparency set\
                    [expr {$fHorX?$horLoop:$corVert}]\
                    [expr {$fHorX?$corVert:$horLoop}] 1
        }
        incr corVert $DCorVert
        incr r $DHor
        incr d [expr { $r / $DVert } ]
        set r [expr { $r % $DVert}]
    }
}