d3.interpolateHsl(a, b) Returns an HSL color space interpolator between the two colors a and b. The colors a and b need not be in HSL; they will be converted to HSL using d3.hsl. If either color’s hue or saturation is NaN, the opposing color’s channel value is used. The shortest path between hues is used. The return value of the interpolator is an RGB string.

path.arc(x, y, radius, startAngle, endAngle[, anticlockwise]) Draws a circular arc segment with the specified center ⟨x, y⟩, radius, startAngle and endAngle. If anticlockwise is true, the arc is drawn in the anticlockwise direction; otherwise, it is drawn in the clockwise direction. If the current point is not equal to the starting point of the arc, a straight line is drawn from the current point to the start of the arc. Equivalent to context.arc and uses SVG’s elliptical arc curve commands.

d3.treemap() Creates a new treemap layout with default settings.

d3.color(specifier) Parses the specified CSS Color Module Level 3 specifier string, returning an RGB or HSL color. If the specifier was not valid, null is returned. Some examples: rgb(255, 255, 255) rgb(10%, 20%, 30%) rgba(255, 255, 255, 0.4) rgba(10%, 20%, 30%, 0.4) hsl(120, 50%, 20%) hsla(120, 50%, 20%, 0.4) #ffeeaa #fea steelblue The list of supported named colors is specified by CSS. Note: this function may also be used with instanceof to test if an object is a color instance. The same

arc.cornerRadius([radius]) If radius is specified, sets the corner radius to the specified function or number and returns this arc generator. If radius is not specified, returns the current corner radius accessor, which defaults to: function cornerRadius() { return 0; } If the corner radius is greater than zero, the corners of the arc are rounded using circles of the given radius. For a circular sector, the two outer corners are rounded; for an annular sector, all four corners are rounded.

arc.centroid(arguments…) Computes the midpoint [x, y] of the center line of the arc that would be generated by the given arguments. The arguments are arbitrary; they are simply propagated to the arc generator’s accessor functions along with the this object. To be consistent with the generated arc, the accessors must be deterministic, i.e., return the same value given the same arguments. The midpoint is defined as (startAngle + endAngle) / 2 and (innerRadius + outerRadius) / 2. For example:

selection.properties(values) A convenience method on top of selection.property for setting multiple element properties. If the specified values is an object, the values may be specified either as strings or functions. For example: selection.properties({foo: "foo-value", id: function(d, i) { return "id-" + i; }}); If a value is a constant, all elements are given the same property value; otherwise, if a value is a function, the function is evaluated for each selected element, in order, being pas

arc.startAngle([angle]) If angle is specified, sets the start angle to the specified function or number and returns this arc generator. If angle is not specified, returns the current start angle accessor, which defaults to: function startAngle(d) { return d.startAngle; } The angle is specified in radians, with 0 at -y (12 o’clock) and positive angles proceeding clockwise. If |endAngle - startAngle| ≥ τ, a complete circle or annulus is generated rather than a sector.

d3.geoGuyou() d3.geoGuyouRaw The Guyou hemisphere-in-a-square projection. Peirce is credited with its quincuncial form.

selection.transition([name]) Returns a new transition on the given selection with the specified name. If a name is not specified, null is used. The new transition is only exclusive with other transitions of the same name. If the name is a transition instance, the returned transition has the same id and name as the specified transition. If a transition with the same id already exists on a selected element, the existing transition is returned for that element. Otherwise, the timing of the retu