From Tcl/Tk 8.6 on, Tk uses Web colours instead of X11 ones, where they conflict.
Along with the color values available for syntactic use in Tcl scripts, several other facts about color might interest programmers. This page aims to collect all this sort of information.
Okay, here's the standard (and rather reliably portable) 6x6x6 color cube. This page has been around forever:
http://the-light.com/colclick.html
The source file which realizes the description which appears in the hyperlink at the top of this page is xlib/xcolor.c. X11 (Unix) systems often have a showrgb command and/or .../lib/X11/rgb.txt which give the same (?) data. Programmatic access to the English-to-RGB-code map is available as
winfo rgb . $colorRS has this wrapper to format the returned list of three decimals to the #RRRRGGGGBBBB form (all in hex) used in color input:
proc colorhash color {eval format #%04X%04X%04X [winfo rgb . $color]}
% colorhash red
#FFFF00000000
% colorhash green
#0000FFFF0000
% colorhash blue
#00000000FFFF
% colorhash white
#FFFFFFFFFFFF
% colorhash black
#000000000000
% colorhash grey50
#7F7F7F7F7F7F"Color pickers" answers common questions on this subject.
The W3C maintains a list [1] of "Web-safe" colors.KPV - here's that list, along with the closest named Tk color:
W3C NAME RGB Closest TK color (~ means not an exact match)
black #000000 => black
silver #C0C0C0 => ~gray75 (or SystemButtonFace on classic Windows)
gray #808080 => ~gray50
white #FFFFFF => white
maroon #800000 => ~darkred
red #FF0000 => red
purple #800080 => ~DarkMagenta
fuchsia #FF00FF => magenta
green #008000 => ~green4
lime #00FF00 => green
olive #808000 => ~Gold4
yellow #FFFF00 => yellow
navy #000080 => navy
blue #0000FF => blue
teal #008080 => ~turquoise4
aqua #00FFFF => cyanNB. what TK calls green is actually lime for W3CMGS 2003/03/21 - These are not the "web-safe" colors - they are the 16 colors defined in HTML 3.2 and 4.01 and correspond to the basic VGA set on PCs. The "browser-safe" colors are constructed from colors where red, green and blue are restricted to the values:RGB 00 51 102 153 204 255 HEX 00 33 66 99 CC FF... which gives 6 * 6 * 6 = 216 different colors.
xcolors is an interesting command under X11.
International Color Consortium maintains a page [2] which has information on ICC color profiles for computer color matching.Mildly related to this is "Selecting visually different RGB colors".
Percent to color: The following routine produces a color from an integer between 0 and 100, where 0 is red, 50 is yellow, and 100 is green (useful e.g. for painting progress bars):
proc percent2rgb {n} {
# map 0..100 to a red-yellow-green sequence
set n [expr {$n < 0? 0: $n > 100? 100: $n}]
set red [expr {$n > 75? 60 - ($n * 15 / 25) : 15}]
set green [expr {$n < 50? $n * 15 / 50 : 15}]
format "#%01x%01x0" $red $green
} ;# RS"Color manipulation" [3] is the name of an ASPN recipe.
Random color: [EE] presented this simple beauty in the Tcl chatroom on 2002-12-18:
proc randomColor {} {format #%06x [expr {int(rand() * 0xFFFFFF)}]}Tk syntax help - Arts and crafts of Tcl-Tk programming[Discuss Death of the Websafe Color Palette?
URL:
http://hotwired.lycos.com/webmonkey/00/37/index2a.html?tw=design
later.]Harmonic color wheel
EKB 1 May 2005Here's code for a "browser-safe color picker." It's still possible that websafe is still useful (although see WebMonkey link above). So given that chance, here's the code if you need it:
package require Iwidgets 4.0
namespace eval bss {
proc change {w rgb dir cmd} {
set curr "0x[$w.$rgb get]"
set new [expr $curr + $dir * 0x33]
if {$new < 0x00} {set new 0xFF}
if {$new > 0xFF} {set new 0x00}
$w.$rgb delete 0 end
$w.$rgb insert 0 [format %2.2X $new]
set color "#[$w.r get][$w.g get][$w.b get]"
setcolor $cmd $color
}
proc setcolor {cmd color} {
# Use "%c" to represent the color
regsub "%c" $cmd $color subcmd
eval $subcmd
}
proc addspinner {w rgb cmd init} {
iwidgets::spinner $w.$rgb -increment "bss::change $w $rgb 1 \{$cmd\}" \
-decrement "bss::change $w $rgb -1 \{$cmd\}" -width 2
$w.$rgb insert 0 $init
pack $w.$rgb -side left
}
proc new {w label cmd {color "#000000"}} {
frame $w
label $w.label -text "$label #"
pack $w.label -side left
addspinner $w r $cmd [string range $color 1 2]
addspinner $w g $cmd [string range $color 3 4]
addspinner $w b $cmd [string range $color 5 6]
setcolor $cmd $color
}
}
#####################################
##
## Implement
##
#####################################
frame .page
frame .spinners
pack .spinners -side right -fill y -expand no -anchor n
pack .page -side left -fill both -expand yes
##------------------------
## Set up the page
##------------------------
text .page.banner -font "Arial 16 bold" -height 1 -width 15 -borderwidth 0
.page.banner insert end "Banner Title"
pack .page.banner -side top -expand no -fill x
text .page.body -font "Arial 10" -height 15 -width 40 -borderwidth 0
.page.body tag configure link -font "Arial 10 bold"
.page.body insert end "This is the body text. This is "
.page.body insert end "a link" link
.page.body insert end ". And this is more text."
pack .page.body -side bottom -expand yes -fill both
##------------------------
## Set up the spinners
##------------------------
#--Banner
label .spinners.bannlbl -text "Banner" -font "Arial 14"
pack .spinners.bannlbl -side top -anchor w -pady 4 -padx 2
bss::new .spinners.bannbg "Background:" {.page.banner configure -bg %c} "#000000"
bss::new .spinners.bannfg "Foreground:" {.page.banner configure -fg %c} "#FFFFFF"
pack .spinners.bannbg -side top -anchor e -pady 2 -padx 2
pack .spinners.bannfg -side top -anchor e -pady 2 -padx 2
#--Body
label .spinners.bodylbl -text "Body" -font "Arial 14"
pack .spinners.bodylbl -side top -anchor w -pady 4 -padx 2
bss::new .spinners.bodybg "Background:" {.page.body configure -bg %c} "#FFFFFF"
bss::new .spinners.bodyfg "Foreground:" {.page.body configure -fg %c} "#000000"
bss::new .spinners.bodylnk "Link:" {.page.body tag configure link -foreground %c} "#0000FF"
pack .spinners.bodybg -side top -anchor e -pady 2 -padx 2
pack .spinners.bodyfg -side top -anchor e -pady 2 -padx 2
pack .spinners.bodylnk -side top -anchor e -pady 2 -padx 2Here's what it looks like:
Also see Web-Safe ColorsRS once suggested
proc random_color {} {format #%06x [expr {int(rand()*0xFFFFFF)}]}exercises a palette. - RS: No, it was EE (see higher up this page :)"Color theory for developers" [4]
EKB My favorite web page for generating color schemes is the Wellstyled [ws] Color Scheme Generator 2 [5].
MG One thing to beware of on Windows is that the platform specific named colours like SystemButtonFace don't seem to be updated for normal Tk widgets after the app is started. This wouldn't really be a problem - except Tile widgets do seem to update, so if you pack a ttk::frame into a regular frame and then change the Windows display settings, they'll end up being different colours, which looks very strange. (And, sadly, makes combining Tk and Ttk widgets that much more difficult.)
