#     font            (Optional) font to be used instead of the default
    #     add_line_space  (Optional) add linespacing or not
    #
    # Result:
    #     List of character width and height
    #
    proc FontMetrics {w {font {}} {add_line_space 0}} {
        if { $font != {} } {
            set item        [$w create text 0 0 -font $font -text "M"]
        } else {
            set item        [$w create text 0 0 -text "M"]
        }
        set bbox        [$w bbox $item]
        set char_width  [expr {[lindex $bbox 2] - [lindex $bbox 0]}]
        set char_height [expr {[lindex $bbox 3] - [lindex $bbox 1]}]
        if { $char_width  <  8 } { set char_width   8 }
        if { $char_height < 14 } { set char_height 14 }
        $w delete $item

        if {$add_line_space} {
            set $char_height [expr {$char_height + [font metrics $font -linespace]}]
        }
        return [list $char_width $char_height]
    }

    #
    # List of styles
    #
    set config(styles) [list]

            set properties $lastProperties
        }
        set config($component,properties) $properties
        set lastProperties $properties
    }

    # get some font properties:
    if {[info command canvas] eq "canvas"} {
        canvas .invisibleCanvas
        set invisibleLabel [.invisibleCanvas create text 0 0 -text "M"]

        foreach {char_width char_height} [FontMetrics .invisibleCanvas] {break}
        set config(font,char_width)  $char_width
        set config(font,char_height) $char_height
        set _font [.invisibleCanvas itemcget $invisibleLabel -font]
    } else {
        foreach {char_width char_height} {12 16} {break}
        set config(font,char_width)  $char_width
        set config(font,char_height) $char_height
        set _font fixed
    }

    # values for the 'default' style:
    set _color         "black"

    set _subtextfont   $_font
    set _subtextcolor  $_color
    set _vsubtextfont  $_font
    set _vsubtextcolor $_color
    set _usesubtext    0
    set _usevsubtext   0
    set _thickness     1

    set _sorted        0      ;# piechart and spiral pie
   #set _shownumbers   0      ;# piechart and spiral pie      - conflict with axes - see below
   #set _format        "%s (%g)"  ;# piechart and spiral pie
    set _formatright   ""         ;# piechart and spiral pie
    set _transposecoordinates 0 ;# horizontal barchart
    set _justify       "left"

    if {[info command canvas] eq "canvas"} {
        destroy .invisibleCanvas
    }

    #
    # Define the 'default' style
    #
    foreach type $config(charttypes) {
        foreach component $config($type,components) {
            foreach property $config($component,properties) {

    if { [string match {[0-9]*} $w] } {
        set w [string range $w [string first . $w] end]
    }

    if { [info exists scaling($ref,refwidth)] && $useref } {
        set width $scaling($ref,refwidth)
    } else {
        if {[info command winfo] eq "winfo" && [winfo exists $w]} {
            set width [winfo width $w]
        } elseif {[catch {$w cget -width} width]} {
            set width 640
        }
        if { $width < 10 } {
            set width [$w cget -width]
        }
    }
    incr width -[$w cget -borderwidth]

    return $width

    if { [string match {[0-9]*} $w] } {
        set w [string range $w [string first . $w] end]
    }

    if { [info exists scaling($ref,refheight)] && $useref } {
        set height $scaling($ref,refheight)
    } else {
        if {[info command winfo] eq "winfo" && [winfo exists $w]} {
            set height [winfo height $w]
        } elseif {[catch {$w cget -height} height]} {
            set height 480
        }
        if { $height < 10 } {
            set height [$w cget -height]
        }
    }
    incr height -[$w cget -borderwidth]
    return $height
}

           }
           set tmpFont $render(subFont)
           set yp1 [expr {round($fontsize/3.0)}]
           set yp2 [expr {-1 * $yp1}]
           set xp1 [expr {round($fontsize/-5.0)}]
           set xp2 [expr {round($fontsize/-5.0)}]
           set advance 1
       }
       "^" { # Superscript
           if {$render(subFont) eq ""} {
               set render(superFont) [font create {*}[font configure $font]]
               set fontsize [font configure $font -size]
               set fontsize [expr {round($fontsize * 3.0/5.0)}]
               font configure $render(superFont) -size $fontsize
           } else {
               set fontsize [$render(superFont) configure -size]
           }
           set tmpFont $render(superFont)
           set yp1 [expr {round($fontsize/-1.5)}]
           set yp2 [expr {-1 * $yp1}]
           set xp1 [expr {round($fontsize/-5.0)}]
           set xp2 [expr {round($fontsize/-5.0)}]
           set advance 1
       }
       default {
           set tmpFont $font
       }
   }
   return [list $xp1 $yp1 $xp2 $yp2 $advance $tmpFont]
}