* * 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. * * @author Nicholas Talian, Vincent Hardy, Jim Graham, Jerry Evans * @author Vincent Hardy * @version $Id: RadialGradientPaint.java,v 1.1 2004/09/06 19:35:39 kitfox Exp $ * */ public final class RadialGradientPaint extends MultipleGradientPaint { /** Focus point which defines the 0% gradient stop x coordinate. */ private Point2D focus; /** Center of the circle defining the 100% gradient stop x coordinate. */ private Point2D center; /** Radius of the outermost circle defining the 100% gradient stop. */ private float radius; /** *
*
* Constructs a RadialGradientPaint, using the center as the
* focus point.
*
* @param 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
*
* @param 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
*
* @param radius the radius of the circle defining the extents of the
* color gradient
*
* @param fractions numbers ranging from 0.0 to 1.0 specifying the
* distribution of colors along the gradient
*
* @param 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 IllegalArgumentException
* if fractions.length != colors.length, or if colors is less
* than 2 in size, or if radius < 0
*
*
*/
public RadialGradientPaint(float cx, float cy, float radius,
float[] fractions, Color[] colors) {
this(cx, cy,
radius,
cx, cy,
fractions,
colors);
}
/**
*
*
* Constructs a RadialGradientPaint, using the center as the
* focus point.
*
* @param center the center point, in user space, of the circle defining
* the gradient
*
* @param radius the radius of the circle defining the extents of the
* color gradient
*
* @param fractions numbers ranging from 0.0 to 1.0 specifying the
* distribution of colors along the gradient
*
* @param 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 NullPointerException if center point is null
*
* @throws IllegalArgumentException
* if fractions.length != colors.length, or if colors is less
* than 2 in size, or if radius < 0
*
*
*/
public RadialGradientPaint(Point2D center, float radius,
float[] fractions, Color[] colors) {
this(center,
radius,
center,
fractions,
colors);
}
/**
*
*
* Constructs a RadialGradientPaint.
*
* @param 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
*
* @param 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
*
* @param radius the radius of the circle defining the extents of the
* color gradient
*
* @param fx the x coordinate of the point in user space to which the
* first color is mapped
*
* @param fy the y coordinate of the point in user space to which the
* first color is mapped
*
* @param fractions numbers ranging from 0.0 to 1.0 specifying the
* distribution of colors along the gradient
*
* @param 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 IllegalArgumentException
* if fractions.length != colors.length, or if colors is less
* than 2 in size, or if radius < 0
*
*
*/
public RadialGradientPaint(float cx, float cy, float radius,
float fx, float fy,
float[] fractions, Color[] colors) {
this(new Point2D.Float(cx, cy),
radius,
new Point2D.Float(fx, fy),
fractions,
colors,
NO_CYCLE,
SRGB);
}
/**
*
*
* Constructs a RadialGradientPaint.
*
* @param 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
*
* @param radius the radius of the circle defining the extents of the color
* gradient
*
* @param focus the point, in user space, to which the first color is
* mapped
*
* @param fractions numbers ranging from 0.0 to 1.0 specifying the
* distribution of colors along the gradient
*
* @param 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 NullPointerException if one of the points is null
*
* @throws IllegalArgumentException
* if fractions.length != colors.length, or if colors is less
* than 2 in size, or if radius < 0
*
*/
public RadialGradientPaint(Point2D center, float radius,
Point2D focus,
float[] fractions, Color[] colors) {
this(center,
radius,
focus,
fractions,
colors,
NO_CYCLE,
SRGB);
}
/**
*
*
* Constructs a RadialGradientPaint.
*
* @param 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
*
* @param radius the radius of the circle defining the extents of the color
* gradient
*
* @param focus the point in user space to which the first color is mapped
*
* @param fractions numbers ranging from 0.0 to 1.0 specifying the
* distribution of colors along the gradient
*
* @param 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.
*
* @param cycleMethod either NO_CYCLE, REFLECT, or REPEAT
*
* @param colorSpace which colorspace to use for interpolation,
* either SRGB or LINEAR_RGB
*
* @throws NullPointerException if one of the points is null
*
* @throws IllegalArgumentException
* if fractions.length != colors.length, or if colors is less
* than 2 in size, or if radius < 0
*
*/
public RadialGradientPaint(Point2D center, float radius,
Point2D focus,
float[] fractions, Color[] colors,
CycleMethodEnum cycleMethod,
ColorSpaceEnum colorSpace) {
this(center,
radius,
focus,
fractions,
colors,
cycleMethod,
colorSpace,
new AffineTransform());
}
/**
*
*
* Constructs a RadialGradientPaint.
*
* @param 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
*
* @param radius the radius of the circle defining the extents of the color
* gradient.
*
* @param focus the point in user space to which the first color is mapped
*
* @param fractions numbers ranging from 0.0 to 1.0 specifying the
* distribution of colors along the gradient
*
* @param 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.
*
* @param cycleMethod either NO_CYCLE, REFLECT, or REPEAT
*
* @param colorSpace which colorspace to use for interpolation,
* either SRGB or LINEAR_RGB
*
* @param gradientTransform transform to apply to the gradient
*
* @throws NullPointerException if one of the points is null,
* or gradientTransform is null
*
* @throws IllegalArgumentException
* if fractions.length != colors.length, or if colors is less
* than 2 in size, or if radius < 0
*
*/
public RadialGradientPaint(Point2D center,
float radius,
Point2D focus,
float[] fractions, Color[] colors,
CycleMethodEnum cycleMethod,
ColorSpaceEnum colorSpace,
AffineTransform gradientTransform){
super(fractions, colors, cycleMethod, colorSpace, gradientTransform);
// Check input arguments
if (center == null) {
throw new NullPointerException("Center point should not be null.");
}
if (focus == null) {
throw new NullPointerException("Focus point should not be null.");
}
if (radius <= 0) {
throw new IllegalArgumentException("radius should be greater than zero");
}
//copy parameters
this.center = (Point2D)center.clone();
this.focus = (Point2D)focus.clone();
this.radius = radius;
}
/**
*
*
* Constructs a RadialGradientPaint, the gradient circle is
* defined by a bounding box.
*
* @param gradientBounds the bounding box, in user space, of the circle
* defining outermost extent of the gradient.
*
* @param fractions numbers ranging from 0.0 to 1.0 specifying the
* distribution of colors along the gradient
*
* @param 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 NullPointerException if the gradientBounds is null
*
* @throws IllegalArgumentException
* if fractions.length != colors.length, or if colors is less
* than 2 in size, or if radius < 0
*
*/
public RadialGradientPaint(Rectangle2D gradientBounds,
float[] fractions, Color[] colors) {
//calculate center point and radius based on bounding box coordinates.
this((float)gradientBounds.getX() +
( (float)gradientBounds.getWidth() / 2),
(float)gradientBounds.getY() +
( (float)gradientBounds.getWidth() / 2),
(float)gradientBounds.getWidth() / 2,
fractions, colors);
}
/**
* Creates and returns a PaintContext used to generate the color pattern,
* for use by the internal rendering engine.
*
* @param cm {@link ColorModel} that receives
* the Paint data. This is used only as a hint.
*
* @param deviceBounds the device space bounding box of the
* graphics primitive being rendered
*
* @param userBounds the user space bounding box of the
* graphics primitive being rendered
*
* @param transform the {@link AffineTransform} from user
* space into device space
*
* @param hints the hints that the context object uses to choose
* between rendering alternatives
*
* @return the {@link PaintContext} that generates color patterns.
*
* @throws IllegalArgumentException if the transform is not invertible
*
* @see PaintContext
*/
public PaintContext createContext(ColorModel cm,
Rectangle deviceBounds,
Rectangle2D userBounds,
AffineTransform transform,
RenderingHints hints) {
// Can't modify the transform passed in...
transform = new AffineTransform(transform);
// incorporate the gradient transform
transform.concatenate(gradientTransform);
try{
return new RadialGradientPaintContext
(cm, deviceBounds, userBounds, transform, hints,
(float)center.getX(), (float)center.getY(), radius,
(float)focus.getX(), (float)focus.getY(),
fractions, colors, cycleMethod, colorSpace);
}
catch(NoninvertibleTransformException e){
throw new IllegalArgumentException("transform should be " +
"invertible");
}
}
/**
* Returns a copy of the center point of the radial gradient.
* @return a {@link Point2D} object that is a copy of the center point
*/
public Point2D getCenterPoint() {
return new Point2D.Double(center.getX(), center.getY());
}
/** Returns a copy of the end point of the gradient axis.
* @return a {@link Point2D} object that is a copy of the focus point
*/
public Point2D getFocusPoint() {
return new Point2D.Double(focus.getX(), focus.getY());
}
/** Returns the radius of the circle defining the radial gradient.
* @return the radius of the circle defining the radial gradient
*/
public float getRadius() {
return radius;
}
}