Version 8 of Rotated canvas text
Updated 2007-06-22 11:54:19 by HJG
Tom Krehbiel shared the following interesting code in the Tcl chatroom, which may display a large E in various rotation angles (X only, not on all Linuxes...):
tomk Are you aware that it is possible to rotate single character in a Tk canvas?
kennykb Rotate single char in Tk canvas? How?
tomk I have some code that someone (smarter than me) posted. I don't remember when or who. You want me to sent you a copy?
kennykb Sure, glad to look at it. This supposed to be Tcl code? Or is someone changing the canvas implementation?
...
proc rotmatrix {size angle} {
set size [expr {double($size)}]
set angle [expr {double($angle)*acos(0.0)/90.0}]; # In radians
set c [expr {$size*cos($angle)}]
set s [expr {$size*sin($angle)}]
# Due to Tk's XLFD (X Logical Font Description)
# parser, we need to round values
set s [format "\[%.f %.f %.f %.f\]" $c [expr {-$s}] $s $c]
regsub -all -- "-" $s ~ s
return $s
}
pack [scrollbar .vs -orient vertical -command {.c yview}] -side right -fill y
pack [scrollbar .hs -orient horizontal -command {.c xview}] -side bottom -fill x
pack [canvas .c -bg white -xscrollcommand {.hs set} -yscrollcommand {.vs set}]\
-side left -expand 1 -fill both
set nb 16
set size 24
set size 64
set text "The Quick Brown Fox jumps over the Lazy Black Dog"
set text "E"
.c configure -scrollregion [list -1000 0 1000 [expr {$size*$nb*2}]]
set x 100
for {set i 0} {$i < 16} {incr i} {
set y [expr {10+$i*$size*2}]
set angle [expr {360.0*$i/$nb}]
.c create text $x $y -text [format "%.1f��° " $angle] -anchor ne -font \
-adobe-times-medium-r-*-*-$size-*-*-*-*-*-*-*
.c create text $x $y -text $text -anchor nw -font \
-adobe-times-medium-r-*-*-[rotmatrix $size $angle]-*-*-*-*-*-*-*
.c create rectangle [expr {$x-2}] [expr {$y-2}] [expr {$x+2}] [expr {$y+2}]\
-outline black -fill red
}suchenwi WOW! YES!
tomk I added the 64 font size and the text "E". If you remove them you get a string version.
kennykb Guys: Before you get too excited, this is Unix-only and not supported by every X server.
suchenwi Works here on Solaris via Reflection, but not native on PC - there the E is only scaled smaller. But it's definitely only recommendable for a single letter...
bschwarz doesn't work on linux
kennykb The functionality is X, mostly. The comment about Tk's XLFD parser has to do with whether Tk will recognize the string as an XLFD or a Tk font name.
trb works on my linux: 2.2.18. XFree86 v 3360 tk 8.3
DKF: Note that the above does not work with an IRIX Xserver.
The BLT extension can also rotate text on a canvas