com.github.gwtd3.api.svg

Class Arc

java.lang.Object

com.google.gwt.core.client.JavaScriptObject

com.github.gwtd3.api.svg.PathDataGenerator

com.github.gwtd3.api.svg.Arc

All Implemented Interfaces:

IsFunction

public class Arc
extends PathDataGenerator

A generator to create an arc by defining the inner radius, the outer radius, the start angle, and the end angle.

Four forms are possible:

• a circle, when the inner radius is zero and the angular span is greater than or equal to 2π
• a circular sector (when the inner radius is zero and the angular span is less than 2π),
• an annulus (when the inner radius is non-zero and the angular span is greater than or equal to 2π),
• an annular sector (when the inner radius is non-zero and the angular span is less than 2π).

Default innerRadius-, outerRadius-, startAngle- and endAngle-accessor functions assume the input data is an object with named attributes matching the accessors.

While the default accessors assume that the arc dimensions are all specified dynamically, it is very common to set one or more of the dimensions as a constant, such as setting the inner radius to zero for a pie chart.

The Arc function generates path data for a closed solid arc, as in a pie or donut chart.

Author:

Anthony Schiochet

See Also:

Official API

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Arc()

Method Summary

Methods

Modifier and Type	Method and Description
String	centroid(int datum, int index) Computes the centroid of the arc that would be generated from the specified input arguments; typically, the arguments are the current datum (d), and optionally the current index (i).
static Arc	constantArc() Create an instance of Arc with all properties being constants initialized to 0.
double	endAngle()
Arc	endAngle(double endAngle) Set the end angle in radians of the Arc.
double	innerRadius()
Arc	innerRadius(double innerRadius) Set the inner radius of the Arc.
double	outerRadius()
Arc	outerRadius(double outerRadius) Set the outerRadius of the Arc.
Arc	setOrInvokeSetter(String propName, double value)
double	startAngle()
Arc	startAngle(double startAngle) Set the start angle in radians of the Arc.

Methods inherited from class com.github.gwtd3.api.svg.PathDataGenerator

generate, generate, generate, generate

Methods inherited from class com.google.gwt.core.client.JavaScriptObject

cast, createArray, createFunction, createObject, equals, hashCode, toSource, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Arc

protected Arc()

Method Detail

innerRadius

public final double innerRadius()

Returns:

the inner radius of the arc.

innerRadius

public final Arc innerRadius(double innerRadius)

Set the inner radius of the Arc.

Parameters:

radius -

Returns:

the current arc generator

outerRadius

public final double outerRadius()

Returns:

the outerRadius of the arc.

outerRadius

public final Arc outerRadius(double outerRadius)

Set the outerRadius of the Arc.

Parameters:

radius -

Returns:

the current arc generator

startAngle

public final double startAngle()

Returns:

the startAngle of the arc.

startAngle

public final Arc startAngle(double startAngle)

Set the start angle in radians of the Arc.

Angles are specified in radians, even though SVG typically uses degrees. The angle 0 corresponds to 12 o'clock (negative y) and continues clockwise repeating at 2xPI.

Parameters:

startAngle - the angle in radians

Returns:

the current arc generator

endAngle

public final double endAngle()

Returns:

the endAngle of the arc.

endAngle

public final Arc endAngle(double endAngle)

Set the end angle in radians of the Arc.

Angles are specified in radians, even though SVG typically uses degrees. The angle 0 corresponds to 12 o'clock (negative y) and continues clockwise repeating at 2xPI.

Parameters:

endAngle - the angle in radians

Returns:

the current arc generator

setOrInvokeSetter

public final Arc setOrInvokeSetter(String propName,
                    double value)

centroid

public final String centroid(int datum,
              int index)

Computes the centroid of the arc that would be generated from the specified input arguments; typically, the arguments are the current datum (d), and optionally the current index (i).

The centroid is defined as the midpoint in polar coordinates of the inner and outer radius, and the start and end angle. This provides a convenient location for arc labels.

TODO: test the result and the possible arguments

Parameters:

datum -

index -

Returns:

constantArc

public static Arc constantArc()

Create an instance of Arc with all properties being constants initialized to 0. Useful to define an arc with constants.

Returns:

an arc object with defaults.