如何将文本从Tcl/Tk库的Canvas对象生成postscript文件?

我已经被这个问题困扰了好几天了:

wm geometry . +0+0
wm resizable . false false
set wtitle "Drawing Chinese Character"
frame .frm -width $pad_width -height $pad_height -relief raised -bd 2
canvas .p0 -width $pad_width -height $pad_height -relief raised -bd 0 
.p0 create rectangle 0 0 $pad_width $pad_height -outline gray -fill white -width 0 
.p0 create text $akx $aky -text "\u9177" -font -Adobe-Times-Bold-R-Normal-*-$fontsize-*  
.p0 create line 0 0 $pad_width $pad_height -fill red -width 2 -arrow last
pack .p0 -in .frm -fill both
pack .frm -side bottom 

update;
.p0 postscript -fontmap fontMap -file "char.ps"