color.opacity This color’s opacity, typically in the range [0, 1].

color.displayable() Returns true if and only if the color is displayable on standard hardware. For example, this returns false for an RGB color if any channel value is less than zero or greater than 255, or if the opacity is not in the range [0, 1].

color.darker([k]) Returns a darker copy of this color. If k is specified, it controls how much darker the returned color should be. If k is not specified, it defaults to 1. The behavior of this method is dependent on the implementing color space.

color.brighter([k]) Returns a brighter copy of this color. If k is specified, it controls how much brighter the returned color should be. If k is not specified, it defaults to 1. The behavior of this method is dependent on the implementing color space.

collide.strength([strength]) If strength is specified, sets the force strength to the specified number in the range [0,1] and returns this force. If strength is not specified, returns the current strength which defaults to 0.7. Overlapping nodes are resolved through iterative relaxation. For each node, the other nodes that are anticipated to overlap at the next tick (using the anticipated positions ⟨x + vx,y + vy⟩) are determined; the node’s velocity is then modified to push the node out of

collide.radius([radius]) If radius is specified, sets the radius accessor to the specified number or function, re-evaluates the radius accessor for each node, and returns this force. If radius is not specified, returns the current radius accessor, which defaults to: function radius() { return 1; } The radius accessor is invoked for each node in the simulation, being passed the node and its zero-based index. The resulting number is then stored internally, such that the radius of each node i

collide.iterations([iterations]) If iterations is specified, sets the number of iterations per application to the specified number and returns this force. If iterations is not specified, returns the current iteration count which defaults to 1. Increasing the number of iterations greatly increases the rigidity of the constraint and avoids partial overlap of nodes, but also increases the runtime cost to evaluate the force.

cluster.size([size]) If size is specified, sets this cluster layout’s size to the specified two-element array of numbers [width, height] and returns this cluster layout. If size is not specified, returns the current layout size, which defaults to [1, 1]. A layout size of null indicates that a node size will be used instead. The coordinates x and y represent an arbitrary coordinate system; for example, to produce a radial layout, a size of [360, radius] corresponds to a breadth of 360° and a

cluster.separation([separation]) If separation is specified, sets the separation accessor to the specified function and returns this cluster layout. If separation is not specified, returns the current separation accessor, which defaults to: function separation(a, b) { return a.parent == b.parent ? 1 : 2; } The separation accessor is used to separate neighboring leaves. The separation function is passed two leaves a and b, and must return the desired separation. The nodes are typically sibl

cluster.nodeSize([size]) If size is specified, sets this cluster layout’s node size to the specified two-element array of numbers [width, height] and returns this cluster layout. If size is not specified, returns the current node size, which defaults to null. A node size of null indicates that a layout size will be used instead. When a node size is specified, the root node is always positioned at ⟨0, 0⟩.