set wheight 400

set wwidth 800

set wwidthsingle [expr $wwidth / 3 ]

set gradient 5

# Aquest -2 és perque els butons, per alguna raó, són 2 pixels més alts i

# amples.

set wheightsingle [expr $wheight / $gradient - 2]

proc stepvalue { min max step } {

	global gradient

	return [expr $min + ( ( $max - $min ) * $step / ($gradient - 1) )]

}

proc color { r g b } {

	return [format "#%04x%04x%04x" $r $g $b]

}

# Build the labels

# Left

label .leftcol.c -height $wheight -width $wwidthsingle -bg #12f \

	-bitmap @gray50.xbm -borderwidth 0

# Center

for {set i 0} {$i < $gradient} {incr i} {

	set r [stepvalue 0 65535 $i]

	set g $r 

	set b $r 

	button .centercol.b$i -height $wheightsingle -width $wwidthsingle \

		-bg [color $r $g $b]  -bitmap gray50 -borderwidth 0 \

		-highlightthickness 0 -command "selection $i"

	pack .centercol.b$i -side top

}

# Right

label .rightcol.c -height $wheight -width $wwidthsingle -bg #f12 \

	-bitmap @gray50.xbm -borderwidth 0

# Global variables

# Loop functions

# Returns { min_r max_r min_g max_g min_b max_b }

set min_r 0

set max_r 65535

set min_g 0

set max_g 0

set min_b 0

set max_b 0

proc getnext { } {

}

proc prepare_colors { } {

	global min_r max_r min_g max_g min_b max_b

}

proc selection { i } {

	puts $i

}