org.apache.batik.util.awt
Class RadialGradientPaint

java.lang.Object
  |
  +--org.apache.batik.util.awt.MultipleGradientPaint
        |
        +--org.apache.batik.util.awt.RadialGradientPaint
All Implemented Interfaces:
java.awt.Paint, java.awt.Transparency

public final class RadialGradientPaint
extends org.apache.batik.util.awt.MultipleGradientPaint

This 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 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).

This paint will map the first color of the gradient to a focus point within the circle, and the last color to the perimeter of the circle, interpolating smoothly for any inbetween colors specified by the user. Any line drawn from the focus point to the circumference will span the all the gradient colors. By default the focus is set to be the center of the circle.

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 perimenter of the circle.

Specifying a cycle method allows the user to control the painting behavior outside of the bounds of the circle's radius. See LinearGradientPaint for more details.

The following code demonstrates typical usage of RadialGradientPaint:

Point2D center = new Point2D.Float(0, 0);
float radius = 20; float[] dist = {0.0, 0.2, 1.0};
Color[] colors = {Color.red, Color.white, Color.blue};
RadialGradientPaint p = new RadialGradientPaint(center, radius, dist, colors);

In the event that the user does not set the first keyframe value equal to 0 and 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}, {.3, .7}
this will be converted to a gradient with the following keyframes: {Color.blue, Color.blue, Color.red, Color.red}, {0, .3, .7, 1}

This image demonstrates a radial gradient with NO_CYCLE and default focus.

This image demonstrates a radial gradient with NO_CYCLE and non-centered focus.

This image demonstrates a radial gradient with REFLECT and non-centered focus.


Inner Class Summary
static class MultipleGradientPaint.ColorSpaceEnum
          Inner class to allow for typesafe enumerated ColorSpace values.
static class MultipleGradientPaint.CycleMethodEnum
          Inner class to allow for typesafe enumerated CycleMethod values.
 
Field Summary
protected  java.awt.Color[] colors
          Gradient colors.
protected  MultipleGradientPaint.ColorSpaceEnum colorSpace
          The colorSpace in which to perform the interpolation.
protected  MultipleGradientPaint.CycleMethodEnum cycleMethod
          The method to use when painting out of the gradient bounds.
protected  float[] fractions
          Gradient keyframe values in the range 0 to 1.
protected  java.awt.geom.AffineTransform gradientTransform
          Transform to apply to gradient.
static MultipleGradientPaint.ColorSpaceEnum LINEAR_RGB
          Indicates that the color interpolation should occur in linearized RGB space.
static MultipleGradientPaint.CycleMethodEnum NO_CYCLE
          Indicates (if the gradient starts or ends inside the target region) to use the terminal colors to fill the remaining area.
static MultipleGradientPaint.CycleMethodEnum REFLECT
          Indicates (if the gradient starts or ends inside the target region), to cycle the gradient colors start-to-end, end-to-start to fill the remaining area.
static MultipleGradientPaint.CycleMethodEnum REPEAT
          Indicates (if the gradient starts or ends inside the target region), to cycle the gradient colors start-to-end, start-to-end to fill the remaining area.
static MultipleGradientPaint.ColorSpaceEnum SRGB
          Indicates that the color interpolation should occur in sRGB space.
protected  int transparency
          Transparency.
 
Fields inherited from interface java.awt.Transparency
BITMASK, OPAQUE, TRANSLUCENT
 
Constructor Summary
RadialGradientPaint(float cx, float cy, float radius, float[] fractions, java.awt.Color[] colors)
           Constructs a RadialGradientPaint, using the center as the focus point.
RadialGradientPaint(float cx, float cy, float radius, float fx, float fy, float[] fractions, java.awt.Color[] colors)
           Constructs a RadialGradientPaint.
RadialGradientPaint(java.awt.geom.Point2D center, float radius, float[] fractions, java.awt.Color[] colors)
           Constructs a RadialGradientPaint, using the center as the focus point.
RadialGradientPaint(java.awt.geom.Point2D center, float radius, java.awt.geom.Point2D focus, float[] fractions, java.awt.Color[] colors)
           Constructs a RadialGradientPaint.
RadialGradientPaint(java.awt.geom.Point2D center, float radius, java.awt.geom.Point2D focus, float[] fractions, java.awt.Color[] colors, MultipleGradientPaint.CycleMethodEnum cycleMethod, MultipleGradientPaint.ColorSpaceEnum colorSpace)
           Constructs a RadialGradientPaint.
RadialGradientPaint(java.awt.geom.Point2D center, float radius, java.awt.geom.Point2D focus, float[] fractions, java.awt.Color[] colors, MultipleGradientPaint.CycleMethodEnum cycleMethod, MultipleGradientPaint.ColorSpaceEnum colorSpace, java.awt.geom.AffineTransform gradientTransform)
           Constructs a RadialGradientPaint.
RadialGradientPaint(java.awt.geom.Rectangle2D gradientBounds, float[] fractions, java.awt.Color[] colors)
           Constructs a RadialGradientPaint, the gradient circle is defined by a bounding box.
 
Method Summary
 java.awt.PaintContext createContext(java.awt.image.ColorModel cm, java.awt.Rectangle deviceBounds, java.awt.geom.Rectangle2D userBounds, java.awt.geom.AffineTransform transform, java.awt.RenderingHints hints)
           Creates and returns a PaintContext used to generate the color pattern, for use by the internal rendering engine.
 java.awt.geom.Point2D getCenterPoint()
          Returns a copy of the center point of the radial gradient.
 java.awt.Color[] getColors()
          Returns a copy of the array of colors used by this gradient.
 MultipleGradientPaint.ColorSpaceEnum getColorSpace()
          Returns the enumerated type which specifies color space for interpolation.
 MultipleGradientPaint.CycleMethodEnum getCycleMethod()
          Returns the enumerated type which specifies cycling behavior.
 java.awt.geom.Point2D getFocusPoint()
          Returns a copy of the end point of the gradient axis.
 float[] getFractions()
          Returns a copy of the array of floats used by this gradient to calculate color distribution.
 float getRadius()
          Returns the radius of the circle defining the radial gradient.
 int getTransparency()
          Returns the transparency mode for this LinearGradientPaint.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

transparency

protected int transparency
Transparency.

fractions

protected float[] fractions
Gradient keyframe values in the range 0 to 1.

colors

protected java.awt.Color[] colors
Gradient colors.

gradientTransform

protected java.awt.geom.AffineTransform gradientTransform
Transform to apply to gradient.

cycleMethod

protected MultipleGradientPaint.CycleMethodEnum cycleMethod
The method to use when painting out of the gradient bounds.

colorSpace

protected MultipleGradientPaint.ColorSpaceEnum colorSpace
The colorSpace in which to perform the interpolation.

NO_CYCLE

public static final MultipleGradientPaint.CycleMethodEnum NO_CYCLE
Indicates (if the gradient starts or ends inside the target region) to use the terminal colors to fill the remaining area. (default)

REFLECT

public static final MultipleGradientPaint.CycleMethodEnum REFLECT
Indicates (if the gradient starts or ends inside the target region), to cycle the gradient colors start-to-end, end-to-start to fill the remaining area.

REPEAT

public static final MultipleGradientPaint.CycleMethodEnum REPEAT
Indicates (if the gradient starts or ends inside the target region), to cycle the gradient colors start-to-end, start-to-end to fill the remaining area.

SRGB

public static final MultipleGradientPaint.ColorSpaceEnum SRGB
Indicates that the color interpolation should occur in sRGB space. (default)

LINEAR_RGB

public static final MultipleGradientPaint.ColorSpaceEnum LINEAR_RGB
Indicates that the color interpolation should occur in linearized RGB space.
Constructor Detail

RadialGradientPaint

public RadialGradientPaint(float cx,
                           float cy,
                           float radius,
                           float[] fractions,
                           java.awt.Color[] colors)

Constructs a RadialGradientPaint, using the center as the focus point.

Parameters:
cx - 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 - 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 - the radius of the circle defining the extents of the color gradient
fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
colors - 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.
Throws:
java.lang.IllegalArgumentException - if fractions.length != colors.length, or if colors is less than 2 in size, or if radius < 0

RadialGradientPaint

public RadialGradientPaint(java.awt.geom.Point2D center,
                           float radius,
                           float[] fractions,
                           java.awt.Color[] colors)

Constructs a RadialGradientPaint, using the center as the focus point.

Parameters:
center - the center point, in user space, of the circle defining the gradient
radius - the radius of the circle defining the extents of the color gradient
fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
colors - 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.
Throws:
java.lang.NullPointerException - if center point is null
java.lang.IllegalArgumentException - if fractions.length != colors.length, or if colors is less than 2 in size, or if radius < 0

RadialGradientPaint

public RadialGradientPaint(float cx,
                           float cy,
                           float radius,
                           float fx,
                           float fy,
                           float[] fractions,
                           java.awt.Color[] colors)

Constructs a RadialGradientPaint.

Parameters:
cx - 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 - 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 - the radius of the circle defining the extents of the color gradient
fx - the x coordinate of the point in user space to which the first color is mapped
fy - the y coordinate of the point in user space to which the first color is mapped
fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
colors - 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.
Throws:
java.lang.IllegalArgumentException - if fractions.length != colors.length, or if colors is less than 2 in size, or if radius < 0

RadialGradientPaint

public RadialGradientPaint(java.awt.geom.Point2D center,
                           float radius,
                           java.awt.geom.Point2D focus,
                           float[] fractions,
                           java.awt.Color[] colors)

Constructs a RadialGradientPaint.

Parameters:
center - 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 - the radius of the circle defining the extents of the color gradient
focus - the point, in user space, to which the first color is mapped
fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
colors - 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.
Throws:
java.lang.NullPointerException - if one of the points is null
java.lang.IllegalArgumentException - if fractions.length != colors.length, or if colors is less than 2 in size, or if radius < 0

RadialGradientPaint

public RadialGradientPaint(java.awt.geom.Point2D center,
                           float radius,
                           java.awt.geom.Point2D focus,
                           float[] fractions,
                           java.awt.Color[] colors,
                           MultipleGradientPaint.CycleMethodEnum cycleMethod,
                           MultipleGradientPaint.ColorSpaceEnum colorSpace)

Constructs a RadialGradientPaint.

Parameters:
center - 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 - the radius of the circle defining the extents of the color gradient
focus - the point in user space to which the first color is mapped
fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
colors - 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 - either NO_CYCLE, REFLECT, or REPEAT
colorSpace - which colorspace to use for interpolation, either SRGB or LINEAR_RGB
Throws:
java.lang.NullPointerException - if one of the points is null
java.lang.IllegalArgumentException - if fractions.length != colors.length, or if colors is less than 2 in size, or if radius < 0

RadialGradientPaint

public RadialGradientPaint(java.awt.geom.Point2D center,
                           float radius,
                           java.awt.geom.Point2D focus,
                           float[] fractions,
                           java.awt.Color[] colors,
                           MultipleGradientPaint.CycleMethodEnum cycleMethod,
                           MultipleGradientPaint.ColorSpaceEnum colorSpace,
                           java.awt.geom.AffineTransform gradientTransform)

Constructs a RadialGradientPaint.

Parameters:
center - 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 - the radius of the circle defining the extents of the color gradient.
focus - the point in user space to which the first color is mapped
fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
colors - 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 - either NO_CYCLE, REFLECT, or REPEAT
colorSpace - which colorspace to use for interpolation, either SRGB or LINEAR_RGB
gradientTransform - transform to apply to the gradient
Throws:
java.lang.NullPointerException - if one of the points is null, or gradientTransform is null
java.lang.IllegalArgumentException - if fractions.length != colors.length, or if colors is less than 2 in size, or if radius < 0

RadialGradientPaint

public RadialGradientPaint(java.awt.geom.Rectangle2D gradientBounds,
                           float[] fractions,
                           java.awt.Color[] colors)

Constructs a RadialGradientPaint, the gradient circle is defined by a bounding box.

Parameters:
gradientBounds - the bounding box, in user space, of the circle defining outermost extent of the gradient.
fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient
colors - 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.
Throws:
java.lang.NullPointerException - if the gradientBounds is null
java.lang.IllegalArgumentException - if fractions.length != colors.length, or if colors is less than 2 in size, or if radius < 0
Method Detail

createContext

public java.awt.PaintContext createContext(java.awt.image.ColorModel cm,
                                           java.awt.Rectangle deviceBounds,
                                           java.awt.geom.Rectangle2D userBounds,
                                           java.awt.geom.AffineTransform transform,
                                           java.awt.RenderingHints hints)

Creates and returns a PaintContext used to generate the color pattern, for use by the internal rendering engine.

Parameters:
cm - ColorModel that receives the Paint data. This is used only as a hint.
deviceBounds - the device space bounding box of the graphics primitive being rendered
userBounds - the user space bounding box of the graphics primitive being rendered
transform - the AffineTransform from user space into device space
hints - the hints that the context object uses to choose between rendering alternatives
Returns:
the PaintContext that generates color patterns.
Throws:
java.lang.IllegalArgumentException - if the transform is not invertible
See Also:
PaintContext

getCenterPoint

public java.awt.geom.Point2D getCenterPoint()
Returns a copy of the center point of the radial gradient.
Returns:
a Point2D object that is a copy of the center point

getFocusPoint

public java.awt.geom.Point2D getFocusPoint()
Returns a copy of the end point of the gradient axis.
Returns:
a Point2D object that is a copy of the focus point

getRadius

public float getRadius()
Returns the radius of the circle defining the radial gradient.
Returns:
the radius of the circle defining the radial gradient

getColors

public java.awt.Color[] getColors()
Returns a copy of the array of colors used by this gradient.
Returns:
a copy of the array of colors used by this gradient

getFractions

public float[] getFractions()
Returns a copy of the array of floats used by this gradient to calculate color distribution.
Returns:
a copy of the array of floats used by this gradient to calculate color distribution

getTransparency

public int getTransparency()
Returns the transparency mode for this LinearGradientPaint.
Specified by:
getTransparency in interface java.awt.Transparency
Returns:
an integer value representing this LinearGradientPaint object's transparency mode.
See Also:
Transparency

getCycleMethod

public MultipleGradientPaint.CycleMethodEnum getCycleMethod()
Returns the enumerated type which specifies cycling behavior.
Returns:
the enumerated type which specifies cycling behavior

getColorSpace

public MultipleGradientPaint.ColorSpaceEnum getColorSpace()
Returns the enumerated type which specifies color space for interpolation.
Returns:
the enumerated type which specifies color space for interpolation


Copyright © 2000 Apache Software Foundation. All Rights Reserved.