Given a value from the domain, returns the corresponding value from the range, subject to interpolation, if any.
If the given value is outside the domain, and clamping is not enabled, the mapping may be extrapolated such that the returned value is outside the range.
Note: The interpolation function applied by the scale may change the output type from the range type as part of the interpolation.
A numeric value from the domain.
Returns whether or not the scale currently clamps values to within the range.
Enables or disables clamping, respectively. If clamping is disabled and the scale is passed a value outside the domain, the scale may return a value outside the range through extrapolation.
If clamping is enabled, the return value of the scale is always within the scale’s range. Clamping similarly applies to the "invert" method.
A flag to enable (true) or disable (false) clamping.
Returns an exact copy of this scale. Changes to this scale will not affect the returned scale, and vice versa.
Returns a copy of the scale’s current domain.
Sets the scale’s domain to the specified array of numbers. The array must contain two or more elements. If the elements in the given array are not numbers, they will be coerced to numbers
Although continuous scales typically have two values each in their domain and range, specifying more than two values produces a piecewise scale.
Internally, a piecewise scale performs a binary search for the range interpolator corresponding to the given domain value. Thus, the domain must be in ascending or descending order. If the domain and range have different lengths N and M, only the first min(N,M) elements in each are observed.
Array of numeric domain values.
If exponent is not specified, returns the current exponent, which defaults to 1. (Note that this is effectively a linear scale until you set a different exponent.)
Sets the current exponent to the given numeric value. (Note that this is effectively a linear scale until you set a different exponent.)
Returns the scale’s current interpolator factory, which defaults to interpolate.
Sets the scale’s range interpolator factory. This interpolator factory is used to create interpolators for each adjacent pair of values from the range; these interpolators then map a normalized domain parameter t in [0, 1] to the corresponding value in the range.
Note: the default interpolator may reuse return values. For example, if the range values are objects, then the value interpolator always returns the same object, modifying it in-place. If the scale is used to set an attribute or style, this is typically acceptable (and desirable for performance); however, if you need to store the scale’s return value, you must specify your own interpolator or make a copy as appropriate.
As part of the interpolation process the interpolated value from the range may be converted to a corresponding output value.
An interpolation factory. The generics for Range and Output of the scale must correspond to the interpolation factory applied to the scale.
Sets the scale’s range interpolator factory. This interpolator factory is used to create interpolators for each adjacent pair of values from the range; these interpolators then map a normalized domain parameter t in [0, 1] to the corresponding value in the range.
Note: the default interpolator may reuse return values. For example, if the range values are objects, then the value interpolator always returns the same object, modifying it in-place. If the scale is used to set an attribute or style, this is typically acceptable (and desirable for performance); however, if you need to store the scale’s return value, you must specify your own interpolator or make a copy as appropriate.
As part of the interpolation process the interpolated value from the range may be converted to a corresponding output value.
The generic "NewOutput" can be used to change the scale to have a different output element type corresponding to the new interpolation factory.
An interpolation factory. The generics for Range and Output of the scale must correspond to the interpolation factory applied to the scale.
Given a value from the range, returns the corresponding value from the domain. Inversion is useful for interaction, say to determine the data value corresponding to the position of the mouse.
If the given value is outside the range, and clamping is not enabled, the mapping may be extrapolated such that the returned value is outside the domain.
IMPORTANT: This method is only supported if the range is numeric. If the range is not numeric, returns NaN.
For a valid value y in the range, continuous(continuous.invert(y)) approximately equals y; similarly, for a valid value x in the domain, continuous.invert(continuous(x)) approximately equals x. The scale and its inverse may not be exact due to the limitations of floating point precision.
A numeric value from the range.
Extends the domain so that it starts and ends on nice round values. This method typically modifies the scale’s domain, and may only extend the bounds to the nearest round value. An optional tick count argument allows greater control over the step size used to extend the bounds, guaranteeing that the returned ticks will exactly cover the domain. Nicing is useful if the domain is computed from data, say using extent, and may be irregular. For example, for a domain of [0.201479…, 0.996679…], a nice domain might be [0.2, 1.0]. If the domain has more than two values, nicing the domain only affects the first and last value.
Nicing a scale only modifies the current domain; it does not automatically nice domains that are subsequently set using continuous.domain. You must re-nice the scale after setting the new domain, if desired.
Optional count: numberAn optional number of ticks expected to be used.
Returns a copy of the scale’s current range.
Sets the scale’s range to the specified array of values.
The array must contain two or more elements. Unlike the domain, elements in the given array need not be numbers; any value that is supported by the underlying interpolator will work, though note that numeric ranges are required for invert.
Array of range values.
Sets the scale’s range to the specified array of values while also setting the scale’s interpolator to interpolateRound.
The rounding interpolator is sometimes useful for avoiding antialiasing artifacts, though also consider the shape-rendering “crispEdges” styles. Note that this interpolator can only be used with numeric ranges.
The array must contain two or more elements. Unlike the domain, elements in the given array need not be numbers; any value that is supported by the underlying interpolator will work, though note that numeric ranges are required for invert.
Array of range values.
Returns a number format function suitable for displaying a tick value, automatically computing the appropriate precision based on the fixed interval between tick values. The specified count should have the same value as the count that is used to generate the tick values.
Optional count: numberApproximate number of ticks to be used when calculating precision for the number format function.
Optional specifier: stringAn optional valid format specifier string which allows a custom format where the precision of the format is automatically set by the scale as appropriate for the tick interval. If specifier uses the format type "s", the scale will return a SI-prefix format based on the largest value in the domain. If the specifier already specifies a precision, this method is equivalent to locale.format.
Returns a number format function suitable for displaying a tick value, automatically computing the appropriate precision based on the fixed interval between tick values. The specified count should have the same value as the count that is used to generate the tick values.
Returns approximately count representative values from the scale’s domain.
If count is not specified, it defaults to 10.
The returned tick values are uniformly spaced, have human-readable values (such as multiples of powers of 10), and are guaranteed to be within the extent of the domain. Ticks are often used to display reference lines, or tick marks, in conjunction with the visualized data. The specified count is only a hint; the scale may return more or fewer values depending on the domain. See also d3-array’s ticks.
Optional count: numberOptional approximate number of ticks to be returned. If count is not specified, it defaults to 10.
Returns the current unknown value, which defaults to undefined.
Sets the output value of the scale for undefined (or NaN) input values and returns this scale.
The output value of the scale for undefined (or NaN) input values.
A continuous power scale defined over a numeric domain.
Continuous scales map a continuous, quantitative input domain to a continuous output range.
Each range value y can be expressed as a function of the domain value x: y = mx^k + b, where k is the exponent value. Power scales also support negative domain values, in which case the input value and the resulting output value are multiplied by -1.
If the range is also numeric, the mapping may be inverted.
Note that the data types of the range and output of the scale must be compatible with the interpolator applied by the scale.
The first generic corresponds to the data type of the range elements.
The second generic corresponds to the data type of the output elements generated by the scale.
The third generic corresponds to the data type of the unknown value.
If range element and output element type differ, the interpolator factory used with the scale must match this behavior and convert the interpolated range element to a corresponding output element.