TIP:            154
Title:          Add Named Colors to Tk
Version:        $Revision: 1.26 $
Author:         Damon Courtney <damon@unreality.com>
State:          Draft
Type:           Project
Vote:           Pending
Created:        03-Sep-2003
Post-History:   
Tcl-Version:    8.7

~ Abstract

This TIP proposes the addition of a '''color''' command at the Tk level to
allow developers to create named colors as they can already do with both fonts
and images.

~ Rationale

Named fonts and images go a long way toward making Tk able to modify a lot of
options on a global scale simply by adjusting a single item. Tk already
simulates some version of named colors on Windows with the use of values like
''SystemButtonFace'' and ''SystemWindowFrame''. These color names map to
values pre-defined in Windows. On UNIX, we have to kind of fake these things
around.

With the addition of named colors, we can simply define default colors in UNIX
that correspond to existing named colors on Windows. So, we could create
''SystemButtonFace'' as a named color on UNIX, and any Windows program using
those color names would port to UNIX without a change.

~ Implementation

I propose the introduction of a new command, '''color''':

 > '''color''' ''option'' ?''arg ...''?

This will have six subcommands.

The '''create''' subcommand creates a new named color.

 > '''color create''' ''colorName'' ?''option ...''?

Supported options (see below for full description) are:

 -color: The main color associated with this named color.

 -dark1: The low-light color associated with this named color.

 -light1: The high-light color associated with this named color.

The '''cget''' subcommand retrieves an option associated with a named color

 > '''color cget''' ''colorName option''

The '''configure''' subcommand sets an option (or options) associted with a
named color, or retrieves information about all the options associated with
that named color (following the standard Tk pattern for cget/configure.)

 > '''color configure''' ''colorName'' ?''option ...''?

The '''exists''' subcommand determines if a named color exists.

 > '''color exists''' ''colorName''

The '''names''' subcommand returns a list of all named colors, including those
created by Tk. The optional glob-style ''pattern'' allows only some colors to
be returned.

 > '''color names''' ?''pattern''?

The '''delete''' subcommand deletes a named color.

 > '''color delete''' ''colorName''

~~Options

The '''-color''' option specifies any acceptable color in Tk as the color to
use. The '''-light1''' and '''-dark1''' options specify the border shadings to
use for this color when it is used as a border. They are named with a 1
because I think in the future we will end up with more levels of shading.
Windows already has two levels, we just ignore the second one.

Beyond the color command, we need to implement a default set of standard
colors that will exist across all platforms. As proposed by some, I think
these should be named Tk*. The current list (reflected in the Windows color
list) would be:

|TkButtonFace
|TkButtonText
|TkDisabledText
|TkHighlight
|TkHighlightText
|TkMenu
|TkMenuText
|TkScrollbar
|TkWindow
|TkWindowFrame
|TkWindowText

If there are others, I'm not sure what they are. This list can easily be
expanded over time as most of them will be created at the Tcl-level.

As part of this TIP, the core widgets should also be modified to use the new
Tk* named colors as their defaults for all platforms. The named colors will
still be created from system defaults on each system. The UNIX colors will
most likely come from whatever comes out of [172].

~ Copyright

This document has been placed in the public domain.
