“ramp_new” creates a color ramp based on a map potential value or based on proximity to a molecular object.
ramp_new name, map_name [, range [, color [, state [, selection [, beyond [, within [, sigma [, zero ]]]]]]]]
name = string: name of the ramp object
map_name = string: name of the map (for potential) or molecular object (for proximity)
range = list: values corresponding to slots in the ramp
color = list: colors corresponding to slots in the ramp
state = integer: state identifier
selection = selection: for automatic ranging
beyond = number: with automatic ranging, are we excluding values beyond a certain distance from the selection?
within = number: with automatic ranging, are we only including valuess within a certain distance from the selection?
sigma = number: with automatic ranging, how many standard deviations from the mean do we go?
zero = integer: with automatic ranging, do we force the central value to be zero?
ramp_new e_pot_color, e_pot_map, [-10,0,10], [red,white,blue]
Color ramps are extremely powerful but complicated to use.
In the simplest case, they can be used to color representations based on the potential values found in a map object at the corresponding positions in space.
In another simple case, representations can be colored based on proximity to a target. Note that since ramp targets must themselves be real objects (not merely selections), the “create” command may be needed in order to generate an appropriate target.
In more complicated cases, they can be used to color representations on one object based atoms found in another.
Ramps can operate recursively. In other words, the output color from one ramp can be used as the input color for another. For example, you could color by map potential within a certain distance of the target object, beyond which, a uniform color is applied.