From Newsgroup: comp.lang.tcl

Hello out there,
is there a function to turn Tk colors' names (like red or chocolate)
into their rgb equivalents?
Thanks for any hints
Helmut
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: comp.lang.tcl

On 8/7/2025 3:47 PM, Helmut Giese wrote:

Hello out there,
is there a function to turn Tk colors' names (like red or chocolate)
into their rgb equivalents?
Thanks for any hints
Helmut

This is what I use:

lassign [winfo rgb . $c] r g b
set r [expr {$r % 256}]
set g [expr {$g % 256}]
set b [expr {$b % 256}]
format "\#%02x%02x%02x" $r $g $b


--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: comp.lang.tcl

At Thu, 07 Aug 2025 21:47:23 +0200 Helmut Giese <hgiese@ratiosoft.com> wrote:

Hello out there,
is there a function to turn Tk colors' names (like red or chocolate)
into their rgb equivalents?
Thanks for any hints

winfo rgb window color
For example:
% winfo rgb . green
0 32896 0
% winfo rgb . orange
65535 42405 0
% winfo rgb . red
65535 0 0
% winfo rgb . chocolate
53970 26985 7710

Helmut

--
Robert Heller -- Cell: 413-658-7953 GV: 978-633-5364
Deepwoods Software -- Custom Software Services
http://www.deepsoft.com/ -- Linux Administration Services
heller@deepsoft.com -- Webhosting Services
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: comp.lang.tcl

On 07/08/2025 22:05, saito wrote:

This is what I use:

lassign [winfo rgb . $c] r g b
set r [expr {$r % 256}]
set g [expr {$g % 256}]
set b [expr {$b % 256}]
format "\#%02x%02x%02x" $r $g $b

Interesting choice to use the least significant byte of the color
values. It happens to work as long as both bytes are the same, which
they seem to be for now. But I would have picked the most significant
byte myself, just in case there may be graphics cards in the future with
more than 8 bits per color.

Within Tk it's also perfectly valid to specify an rgb value with 4 hex
chars per color. So for that use case you could just simplify to:
format #%04x%04x%04x {*}[winfo rgb . $c]


Schelte.

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: comp.lang.tcl

On 8/7/2025 5:00 PM, Schelte wrote:

Interesting choice to use the least significant byte of the color
values. It happens to work as long as both bytes are the same, which
they seem to be for now. But I would have picked the most significant
byte myself, just in case there may be graphics cards in the future with more than 8 bits per color.

This piece of code is quite old. Thanks for the info though, I didn't
know that.



--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: comp.lang.tcl

Sorry for the delay.
Thanks to all of you.
Robert, 'winfo rgb' was exactly what I was looking for.
Helmut
--- Synchronet 3.21a-Linux NewsLink 1.2