Top Description Fields Constructors Methods
com.sun.prism.j2d.paint

public final Class RadialGradientPaint

extends MultipleGradientPaint
Class Inheritance
Imports
java.awt.Color, .PaintContext, .Rectangle, .RenderingHints, java.awt.geom.AffineTransform, .Point2D, .Rectangle2D, java.awt.image.ColorModel
The RadialGradientPaint class provides a way to fill a shape with a circular radial color gradient pattern. The user may specify 2 or more gradient colors, and this paint will provide an interpolation between each color.

The user must specify the circle controlling the gradient pattern, which is described by a center point and a radius. The user can also specify a separate focus point within that circle, which controls the location of the first color of the gradient. By default the focus is set to be the center of the circle.

This paint will map the first color of the gradient to the focus point, and the last color to the perimeter of the circle, interpolating smoothly for any in-between colors specified by the user. Any line drawn from the focus point to the circumference will thus span all the gradient colors.

Specifying a focus point outside of the circle's radius will result in the focus being set to the intersection point of the focus-center line and the perimeter of the circle.

The user must provide an array of floats specifying how to distribute the colors along the gradient. These values should range from 0.0 to 1.0 and act like keyframes along the gradient (they mark where the gradient should be exactly a particular color).

In the event that the user does not set the first keyframe value equal to 0 and/or the last keyframe value equal to 1, keyframes will be created at these positions and the first and last colors will be replicated there. So, if a user specifies the following arrays to construct a gradient:

    {Color.BLUE, Color.RED}, {.3f, .7f}
this will be converted to a gradient with the following keyframes:
    {Color.BLUE, Color.BLUE, Color.RED, Color.RED}, {0f, .3f, .7f, 1f}

The user may also select what action the RadialGradientPaint should take when filling color outside the bounds of the circle's radius. If no cycle method is specified, NO_CYCLE will be chosen by default, which means the the last keyframe color will be used to fill the remaining area.

The colorSpace parameter allows the user to specify in which colorspace the interpolation should be performed, default sRGB or linearized RGB.

The following code demonstrates typical usage of RadialGradientPaint, where the center and focus points are the same: 

    Point2D center = new Point2D.Float(50, 50);
    float radius = 25;
    float[] dist = {0.0f, 0.2f, 1.0f};
    Color[] colors = {Color.RED, Color.WHITE, Color.BLUE};
    RadialGradientPaint p =
        new RadialGradientPaint(center, radius, dist, colors);

This image demonstrates the example code above, with default (centered) focus for each of the three cycle methods:

It is also possible to specify a non-centered focus point, as in the following code: 

    Point2D center = new Point2D.Float(50, 50);
    float radius = 25;
    Point2D focus = new Point2D.Float(40, 40);
    float[] dist = {0.0f, 0.2f, 1.0f};
    Color[] colors = {Color.RED, Color.WHITE, Color.BLUE};
    RadialGradientPaint p =
        new RadialGradientPaint(center, radius, focus,
                                dist, colors,
                                CycleMethod.NO_CYCLE);

This image demonstrates the previous example code, with non-centered focus for each of the three cycle methods:

See Also
java.awt.Paint, java.awt.Graphics2D#setPaint

Field Summary

Modifier and TypeField and Description
private final Point2D
center

Center of the circle defining the 100% gradient stop X coordinate.

private final Point2D
focus

Focus point which defines the 0% gradient stop X coordinate.

private final float
radius

Radius of the outermost circle defining the 100% gradient stop.

Inherited from com.sun.prism.j2d.paint.MultipleGradientPaint:
colorscolorSpacecycleMethodfastGradientArraySizefractionsgradientgradientsgradientTransformisSimpleLookupmodelnormalizedIntervalstransparency

Constructor Summary

AccessConstructor and Description
public
RadialGradientPaint(float
the X coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.
cx, float
the Y coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.
cy, float
the radius of the circle defining the extents of the color gradient
radius, float[]
numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
fractions, Color[]
array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.
colors)

Constructs a RadialGradientPaint with a default NO_CYCLE repeating method and SRGB color space, using the center as the focus point.

public
RadialGradientPaint(Point2D
the center point, in user space, of the circle defining the gradient
center, float
the radius of the circle defining the extents of the color gradient
radius, float[]
numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
fractions, Color[]
array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.
colors)

Constructs a RadialGradientPaint with a default NO_CYCLE repeating method and SRGB color space, using the center as the focus point.

public
RadialGradientPaint(float
the X coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.
cx, float
the Y coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.
cy, float
the radius of the circle defining the extents of the color gradient
radius, float[]
numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
fractions, Color[]
array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.
colors, MultipleGradientPaint.CycleMethod
either NO_CYCLE, REFLECT, or REPEAT
cycleMethod)

Constructs a RadialGradientPaint with a default SRGB color space, using the center as the focus point.

public
RadialGradientPaint(Point2D
the center point, in user space, of the circle defining the gradient
center, float
the radius of the circle defining the extents of the color gradient
radius, float[]
numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
fractions, Color[]
array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.
colors, MultipleGradientPaint.CycleMethod
either NO_CYCLE, REFLECT, or REPEAT
cycleMethod)

Constructs a RadialGradientPaint with a default SRGB color space, using the center as the focus point.

public
RadialGradientPaint(float
the X coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.
cx, float
the Y coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.
cy, float
the radius of the circle defining the extents of the color gradient
radius, float
the X coordinate of the point in user space to which the first color is mapped
fx, float
the Y coordinate of the point in user space to which the first color is mapped
fy, float[]
numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
fractions, Color[]
array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.
colors, MultipleGradientPaint.CycleMethod
either NO_CYCLE, REFLECT, or REPEAT
cycleMethod)

Constructs a RadialGradientPaint with a default SRGB color space.

public
RadialGradientPaint(Point2D
the center point, in user space, of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.
center, float
the radius of the circle defining the extents of the color gradient
radius, Point2D
the point in user space to which the first color is mapped
focus, float[]
numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
fractions, Color[]
array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.
colors, MultipleGradientPaint.CycleMethod
either NO_CYCLE, REFLECT, or REPEAT
cycleMethod)

Constructs a RadialGradientPaint with a default SRGB color space.

public
RadialGradientPaint(Point2D
the center point in user space of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.
center, float
the radius of the circle defining the extents of the color gradient
radius, Point2D
the point in user space to which the first color is mapped
focus, float[]
numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
fractions, Color[]
array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.
colors, MultipleGradientPaint.CycleMethod
either NO_CYCLE, REFLECT, or REPEAT
cycleMethod, MultipleGradientPaint.ColorSpaceType
which color space to use for interpolation, either SRGB or LINEAR_RGB
colorSpace, AffineTransform
transform to apply to the gradient
gradientTransform)

Constructs a RadialGradientPaint.

public
RadialGradientPaint(Rectangle2D
the bounding box, in user space, of the circle defining the outermost extent of the gradient
gradientBounds, float[]
numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
fractions, Color[]
array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.
colors, MultipleGradientPaint.CycleMethod
either NO_CYCLE, REFLECT, or REPEAT
cycleMethod)

Constructs a RadialGradientPaint with a default SRGB color space.

Method Summary

Modifier and TypeMethod and Description
public PaintContext
createContext(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform transform, RenderingHints hints)

Implements java.awt.Paint.createContext.

Creates and returns a PaintContext used to generate the color pattern.

private static AffineTransform
createGradientTransform(Rectangle2D r)

public Point2D

Returns:

a Point2D object that is a copy of the center point
getCenterPoint()

Returns a copy of the center point of the radial gradient.

public Point2D

Returns:

a Point2D object that is a copy of the focus point
getFocusPoint()

Returns a copy of the end point of the gradient axis.

public float

Returns:

the radius of the circle defining the radial gradient
getRadius()

Returns the radius of the circle defining the radial gradient.

Inherited from com.sun.prism.j2d.paint.MultipleGradientPaint:
getColorsgetColorSpacegetCycleMethodgetFractionsgetTransformgetTransparency

Field Detail

centerback to summary
private final Point2D center

Center of the circle defining the 100% gradient stop X coordinate.

focusback to summary
private final Point2D focus

Focus point which defines the 0% gradient stop X coordinate.

radiusback to summary
private final float radius

Radius of the outermost circle defining the 100% gradient stop.

Constructor Detail

RadialGradientPaintback to summary
public RadialGradientPaint(float cx, float cy, float radius, float[] fractions, Color[] colors)

Constructs a RadialGradientPaint with a default NO_CYCLE repeating method and SRGB color space, using the center as the focus point.

Parameters
cx:float

the X coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.

cy:float

the Y coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.

radius:float

the radius of the circle defining the extents of the color gradient

fractions:float[]

numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors:Color[]

array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.

Exceptions
NullPointerException:
if fractions array is null, or colors array is null
IllegalArgumentException:
if radius is non-positive, or fractions.length != colors.length, or colors is less than 2 in size, or a fractions value is less than 0.0 or greater than 1.0, or the fractions are not provided in strictly increasing order
RadialGradientPaintback to summary
public RadialGradientPaint(Point2D center, float radius, float[] fractions, Color[] colors)

Constructs a RadialGradientPaint with a default NO_CYCLE repeating method and SRGB color space, using the center as the focus point.

Parameters
center:Point2D

the center point, in user space, of the circle defining the gradient

radius:float

the radius of the circle defining the extents of the color gradient

fractions:float[]

numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors:Color[]

array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.

Exceptions
NullPointerException:
if center point is null, or fractions array is null, or colors array is null
IllegalArgumentException:
if radius is non-positive, or fractions.length != colors.length, or colors is less than 2 in size, or a fractions value is less than 0.0 or greater than 1.0, or the fractions are not provided in strictly increasing order
RadialGradientPaintback to summary
public RadialGradientPaint(float cx, float cy, float radius, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod)

Constructs a RadialGradientPaint with a default SRGB color space, using the center as the focus point.

Parameters
cx:float

the X coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.

cy:float

the Y coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.

radius:float

the radius of the circle defining the extents of the color gradient

fractions:float[]

numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors:Color[]

array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.

cycleMethod:MultipleGradientPaint.CycleMethod

either NO_CYCLE, REFLECT, or REPEAT

Exceptions
NullPointerException:
if fractions array is null, or colors array is null, or cycleMethod is null
IllegalArgumentException:
if radius is non-positive, or fractions.length != colors.length, or colors is less than 2 in size, or a fractions value is less than 0.0 or greater than 1.0, or the fractions are not provided in strictly increasing order
RadialGradientPaintback to summary
public RadialGradientPaint(Point2D center, float radius, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod)

Constructs a RadialGradientPaint with a default SRGB color space, using the center as the focus point.

Parameters
center:Point2D

the center point, in user space, of the circle defining the gradient

radius:float

the radius of the circle defining the extents of the color gradient

fractions:float[]

numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors:Color[]

array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.

cycleMethod:MultipleGradientPaint.CycleMethod

either NO_CYCLE, REFLECT, or REPEAT

Exceptions
NullPointerException:
if center point is null, or fractions array is null, or colors array is null, or cycleMethod is null
IllegalArgumentException:
if radius is non-positive, or fractions.length != colors.length, or colors is less than 2 in size, or a fractions value is less than 0.0 or greater than 1.0, or the fractions are not provided in strictly increasing order
RadialGradientPaintback to summary
public RadialGradientPaint(float cx, float cy, float radius, float fx, float fy, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod)

Constructs a RadialGradientPaint with a default SRGB color space.

Parameters
cx:float

the X coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.

cy:float

the Y coordinate in user space of the center point of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.

radius:float

the radius of the circle defining the extents of the color gradient

fx:float

the X coordinate of the point in user space to which the first color is mapped

fy:float

the Y coordinate of the point in user space to which the first color is mapped

fractions:float[]

numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors:Color[]

array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.

cycleMethod:MultipleGradientPaint.CycleMethod

either NO_CYCLE, REFLECT, or REPEAT

Exceptions
NullPointerException:
if fractions array is null, or colors array is null, or cycleMethod is null
IllegalArgumentException:
if radius is non-positive, or fractions.length != colors.length, or colors is less than 2 in size, or a fractions value is less than 0.0 or greater than 1.0, or the fractions are not provided in strictly increasing order
RadialGradientPaintback to summary
public RadialGradientPaint(Point2D center, float radius, Point2D focus, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod)

Constructs a RadialGradientPaint with a default SRGB color space.

Parameters
center:Point2D

the center point, in user space, of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.

radius:float

the radius of the circle defining the extents of the color gradient

focus:Point2D

the point in user space to which the first color is mapped

fractions:float[]

numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors:Color[]

array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.

cycleMethod:MultipleGradientPaint.CycleMethod

either NO_CYCLE, REFLECT, or REPEAT

Exceptions
NullPointerException:
if one of the points is null, or fractions array is null, or colors array is null, or cycleMethod is null
IllegalArgumentException:
if radius is non-positive, or fractions.length != colors.length, or colors is less than 2 in size, or a fractions value is less than 0.0 or greater than 1.0, or the fractions are not provided in strictly increasing order
RadialGradientPaintback to summary
public RadialGradientPaint(Point2D center, float radius, Point2D focus, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod, MultipleGradientPaint.ColorSpaceType colorSpace, AffineTransform gradientTransform)

Constructs a RadialGradientPaint.

Parameters
center:Point2D

the center point in user space of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.

radius:float

the radius of the circle defining the extents of the color gradient

focus:Point2D

the point in user space to which the first color is mapped

fractions:float[]

numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors:Color[]

array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.

cycleMethod:MultipleGradientPaint.CycleMethod

either NO_CYCLE, REFLECT, or REPEAT

colorSpace:MultipleGradientPaint.ColorSpaceType

which color space to use for interpolation, either SRGB or LINEAR_RGB

gradientTransform:AffineTransform

transform to apply to the gradient

Exceptions
NullPointerException:
if one of the points is null, or fractions array is null, or colors array is null, or cycleMethod is null, or colorSpace is null, or gradientTransform is null
IllegalArgumentException:
if radius is non-positive, or fractions.length != colors.length, or colors is less than 2 in size, or a fractions value is less than 0.0 or greater than 1.0, or the fractions are not provided in strictly increasing order
RadialGradientPaintback to summary
public RadialGradientPaint(Rectangle2D gradientBounds, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod)

Constructs a RadialGradientPaint with a default SRGB color space. The gradient circle of the RadialGradientPaint is defined by the given bounding box.

This constructor is a more convenient way to express the following (equivalent) code:

    double gw = gradientBounds.getWidth();
    double gh = gradientBounds.getHeight();
    double cx = gradientBounds.getCenterX();
    double cy = gradientBounds.getCenterY();
    Point2D center = new Point2D.Double(cx, cy);

    AffineTransform gradientTransform = new AffineTransform();
    gradientTransform.translate(cx, cy);
    gradientTransform.scale(gw / 2, gh / 2);
    gradientTransform.translate(-cx, -cy);

    RadialGradientPaint gp =
        new RadialGradientPaint(center, 1.0f, center,
                                fractions, colors,
                                cycleMethod,
                                ColorSpaceType.SRGB,
                                gradientTransform);
Parameters
gradientBounds:Rectangle2D

the bounding box, in user space, of the circle defining the outermost extent of the gradient

fractions:float[]

numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors:Color[]

array of colors to use in the gradient. The first color is used at the focus point, the last color around the perimeter of the circle.

cycleMethod:MultipleGradientPaint.CycleMethod

either NO_CYCLE, REFLECT, or REPEAT

Exceptions
NullPointerException:
if gradientBounds is null, or fractions array is null, or colors array is null, or cycleMethod is null
IllegalArgumentException:
if gradientBounds is empty, or fractions.length != colors.length, or colors is less than 2 in size, or a fractions value is less than 0.0 or greater than 1.0, or the fractions are not provided in strictly increasing order

Method Detail

createContextback to summary
public PaintContext createContext(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform transform, RenderingHints hints)

Implements java.awt.Paint.createContext.

Doc from java.awt.Paint.createContext.

Creates and returns a PaintContext used to generate the color pattern. The arguments to this method convey additional information about the rendering operation that may be used or ignored on various implementations of the Paint interface. A caller must pass non-null values for all of the arguments except for the ColorModel argument which may be null to indicate that no specific ColorModel type is preferred. Implementations of the Paint interface are allowed to use or ignore any of the arguments as makes sense for their function, and are not constrained to use the specified ColorModel for the returned PaintContext, even if it is not null. Implementations are allowed to throw NullPointerException for any null argument other than the ColorModel argument, but are not required to do so.

Annotations
@Override
createGradientTransformback to summary
private static AffineTransform createGradientTransform(Rectangle2D r)
getCenterPointback to summary
public Point2D getCenterPoint()

Returns a copy of the center point of the radial gradient.

Returns:Point2D

a Point2D object that is a copy of the center point

getFocusPointback to summary
public Point2D getFocusPoint()

Returns a copy of the end point of the gradient axis.

Returns:Point2D

a Point2D object that is a copy of the focus point

getRadiusback to summary
public float getRadius()

Returns the radius of the circle defining the radial gradient.

Returns:float

the radius of the circle defining the radial gradient