MGS [2003/04/06] - In order to draw rectangles on a canvas with a raised/sunken relief, you need to know how to compute the colors of the 3d beveled edges - the light and dark shadows. I converted tk8.4.0/unix/tkUnix3d.c to pure tcl code:
# ======================================================================
namespace eval color {
variable MAX_INTENSITY 65535
}
# ======================================================================
# shadow:dark --
# Compute the dark shadow color for a 3d border.
# Cut 40% from each of the color components. If the background is
# already very dark, make the dark color a little lighter than the
# background by increasing each color component 1/4th of the way to
# MAX_INTENSITY.
# This adapted from tk8.4.0/unix/tkUnix3d.c
proc color::shadow:dark {R G B} {
# ----------------------------------------------------------------------
variable MAX_INTENSITY
# ----------------------------------------------------------------------
if { [expr {($R*0.5*$R) + ($G*1.0*$G) + ($B*0.28*$B)}] <
[expr {$MAX_INTENSITY*0.05*$MAX_INTENSITY}] } {
set r [expr {($MAX_INTENSITY + 3*$R)/4}]
set g [expr {($MAX_INTENSITY + 3*$G)/4}]
set b [expr {($MAX_INTENSITY + 3*$B)/4}]
} else {
set r [expr {(60 * $R)/100}]
set g [expr {(60 * $G)/100}]
set b [expr {(60 * $B)/100}]
}
# ----------------------------------------------------------------------
return [format #%04X%04X%04X $r $g $b]
}
# ======================================================================# shadow:light --
# Compute the light shadow color for a 3d border.
# Boost each component by 40% or half-way to white, whichever is greater
# (the first approach works better for unsaturated colors, the second
# for saturated ones). If the background is already very bright, instead
# choose a slightly darker color for the light shadow by reducing each
# color component by 10%.
# This adapted from tk8.4.0/unix/tkUnix3d.c
proc color::shadow:light {R G B} {
# ----------------------------------------------------------------------
variable MAX_INTENSITY
# ----------------------------------------------------------------------
if { $G > [expr {$MAX_INTENSITY*0.95}] } {
set r [expr {(90 * $R)/100}]
set g [expr {(90 * $G)/100}]
set b [expr {(90 * $B)/100}]
} else {
set tmp1 [expr {(14 * $R)/10}]
if { $tmp1 > $MAX_INTENSITY } { set tmp1 $MAX_INTENSITY }
set tmp2 [expr {($MAX_INTENSITY + $R)/2}]
set r [expr {($tmp1 > $tmp2) ? $tmp1 : $tmp2}]
set tmp1 [expr {(14 * $G)/10}]
if { $tmp1 > $MAX_INTENSITY } { set tmp1 $MAX_INTENSITY }
set tmp2 [expr {($MAX_INTENSITY + $G)/2}]
set g [expr {($tmp1 > $tmp2) ? $tmp1 : $tmp2}]
set tmp1 [expr {(14 * $B)/10}]
if { $tmp1 > $MAX_INTENSITY } { set tmp1 $MAX_INTENSITY }
set tmp2 [expr {($MAX_INTENSITY + $B)/2}]
set b [expr {($tmp1 > $tmp2) ? $tmp1 : $tmp2}]
}
# ----------------------------------------------------------------------
return [format #%04X%04X%04X $r $g $b]
}
# ======================================================================
# demo code
proc rect {c x1 y1 x2 y2 bd color} {
set dark [eval color::shadow:dark [winfo rgb $c $color]]
set light [eval color::shadow:light [winfo rgb $c $color]]
puts "dark $color = \[$dark\]"
puts "light $color = \[$light\]"
$c create polygon \
$x1 $y1 \
$x2 $y1 \
[expr $x2 - $bd] [expr $y1 + $bd] \
[expr $x1 + $bd] [expr $y1 + $bd] \
[expr $x1 + $bd] [expr $y2 - $bd] \
$x1 $y2 \
-fill $light \
-outline $light
$c create polygon \
$x2 $y1 \
$x2 $y2 \
$x1 $y2 \
[expr $x1 + $bd] [expr $y2 - $bd] \
[expr $x2 - $bd] [expr $y2 - $bd] \
[expr $x2 - $bd] [expr $y1 + $bd] \
-fill $dark \
-outline $dark
$c create rectangle \
[expr $x1 + $bd] [expr $y1 + $bd] \
[expr $x2 - $bd] [expr $y2 - $bd] \
-fill $color \
-outline $color
return
}
button .b -text "Hello World" -bg red -fg white -bd 10
canvas .c
pack .b
pack .c -expand 1 -fill both
update idletasks
rect .c 10 10 \
[expr [winfo width .b] + 10] \
[expr [winfo height .b] + 10] \
10 red
# ======================================================================Note that RGB values are specified as 16-bit values, as returned from [winfo rgb].
Note that at least on Microsoft Windows, I changed the winfo width/height to winfo reqwidth/reqheight. Otherwise you get an incorrect width/height. (I would have thought the update would have taken care of this??) Brett Schwarz