01  function color_coldhotrev( color )
02    dim sample: sample = color_rgb( color )
03  
04    sample( COLOR_R ) = sample( COLOR_R ) / NUMBER_MAX_BYTE
05    sample( COLOR_G ) = sample( COLOR_G ) / NUMBER_MAX_BYTE
06    sample( COLOR_B ) = sample( COLOR_B ) / NUMBER_MAX_BYTE
07  
08    dim r: r = ( sample( COLOR_R ) = 1.0 )
09    dim g: g = ( sample( COLOR_G ) = 1.0 )
10    dim b: b = ( sample( COLOR_B ) = 1.0 )
11  
12    if( ( not r ) and b ) then
13      color_coldhotrev = sample( COLOR_G ) / 4.0
14    elseif( ( not r ) and g ) then
15      color_coldhotrev = 0.5 - sample( COLOR_B ) / 4.0
16    elseif( g and ( not b ) ) then
17      color_coldhotrev = 0.5 + sample( COLOR_R ) / 4.0
18    elseif( r and ( not b ) ) then
19      color_coldhotrev = 1.0 - sample( COLOR_G ) / 4.0
20    else
21      color_coldhotrev = -1.0
22    end if
23  end function