tk_chooseColor

pops up a dialog box for the user to select a color.

http://purl.org/tcl/home/man/tcl8.4/TkCmd/chooseColor.htm

SYNOPSIS

tk_chooseColor ?option value ...?

DESCRIPTION

The procedure tk_chooseColor pops up a dialog box for the user to select a color. The following option-value pairs are possible as command line arguments:

-initialcolor color

Specifies the color to display in the color dialog when it pops up. Color must be in a form acceptable to the Tk_GetColor function.

-parent window

Makes window the logical parent of the color dialog. The color dialog is displayed on top of its parent window.

-title titleString

Specifies a string to display as the title of the dialog box. If this option is not specified, then a default title will be displayed.

If the user selects a color, tk_chooseColor will return the name of the color in a form acceptable to Tk_GetColor. If the user cancels the operation, the command will return the empty string.

EXAMPLE

 button .b -bg [tk_chooseColor -initialcolor gray -title "Choose color"]

A minimal example:

 button .b_fg -text "Set Foreground Color" -command {fg_color}
 button .b_bg -text "Set Background Color" -command {bg_color}
 label .l -text "Foreground Color on Background Color"

 grid .b_fg .b_bg -sticky ew
 grid .l -row 1 -columnspan 2 -sticky ew

 proc fg_color { } {
	set color [tk_chooseColor]
	.l configure -fg $color
	}

 proc bg_color { } {
	set color [tk_chooseColor]
	.l configure -bg $color
	}

 wm title . "tk_chooseColor Example"

RS: A style note - no doubt this works as planned, but for more reusable (and also more compact) code, why not pass in the target widget, and the target attribute as well?

 button .b_fg -text "Set Foreground Color" -command {color .l -fg}
 button .b_bg -text "Set Background Color" -command {color .l -bg}
 label .l -text "Foreground Color on Background Color"

 grid .b_fg .b_bg -sticky ew
 grid .l -row 1 -columnspan 2 -sticky ew

 proc color {w what} {
	set color [tk_chooseColor]
	$w configure $what $color
 }

For a tiny bit more safety, CL recommends instead

    proc color {w what} {
        set color [tk_chooseColor]
            # "Cancel" means, "do nothing".
        if [string equal $color ""] return
        $w configure $what $color
    }

Michael Schlenker contributed the following example of the use of this function over on comp.lang.tcl:

 # set color variable to color value returned from tk_chooseColor
 set color [tk_chooseColor]
 # be .c an canvas with some objects in it , sets the -fill color of all
 # items to $color
 .c itemconfigure all -fill $color

Robert Heller also answered in the same comp.lang.tcl thread with this code fragment:

 canvas .thecanvas
 pack .thecanvas
 .thecanvas create oval 0 0 50 50 -fill red -outline blue -tag theOval
 .thecanvas itemconfigure theOval -fill \
        [tk_chooseColor -initialcolor [.thecanvas itemcget theOval -fill]]
 .thecanvas itemconfigure theOval -outline \
        [tk_chooseColor -initialcolor [.thecanvas itemcget theOval -outline]]

Arts and Crafts of Tcl-Tk Programming

Category Command - Category Dialog - Category GUI - Tk syntax help