[min] minimal value, lower bound | number | |
[max] maximal value, upper bound | number | |
[low] first color point (yellow if optimum is at a lower end, red if it is at the higher end) | number | |
[high] second color point (red if optimum is at a lower end, yellow if it is at the higher end) | number | |
[optimum] third color point (green, representing preferred value) | number | |
[value] current value | number |