/*
* @(#)GradientPaint.java 1.39 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.awt;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.awt.geom.AffineTransform;
import java.awt.image.ColorModel;
/**
* The <code>GradientPaint</code> class provides a way to fill
* a {@link Shape} with a linear color gradient pattern.
* If {@link Point} P1 with {@link Color} C1 and <code>Point</code> P2 with
* <code>Color</code> C2 are specified in user space, the
* <code>Color</code> on the P1, P2 connecting line is proportionally
* changed from C1 to C2. Any point P not on the extended P1, P2
* connecting line has the color of the point P' that is the perpendicular
* projection of P on the extended P1, P2 connecting line.
* Points on the extended line outside of the P1, P2 segment can be colored
* in one of two ways.
* <ul>
* <li>
* If the gradient is cyclic then the points on the extended P1, P2
* connecting line cycle back and forth between the colors C1 and C2.
* <li>
* If the gradient is acyclic then points on the P1 side of the segment
* have the constant <code>Color</code> C1 while points on the P2 side
* have the constant <code>Color</code> C2.
* </ul>
*
* @see Paint
* @see Graphics2D#setPaint
* @version 10 Feb 1997
*/
public class GradientPaint implements Paint {
Point2D.Float p1;
Point2D.Float p2;
Color color1;
Color color2;
boolean cyclic;
/**
* Constructs a simple acyclic <code>GradientPaint</code> object.
* @param x1 x coordinate of the first specified
* <code>Point</code> in user space
* @param y1 y coordinate of the first specified
* <code>Point</code> in user space
* @param color1 <code>Color</code> at the first specified
* <code>Point</code>
* @param x2 x coordinate of the second specified
* <code>Point</code> in user space
* @param y2 y coordinate of the second specified
* <code>Point</code> in user space
* @param color2 <code>Color</code> at the second specified
* <code>Point</code>
* @throws NullPointerException if either one of colors is null
*/
public GradientPaint(float x1,
float y1,
Color color1,
float x2,
float y2,
Color color2) {
if ((color1 == null) || (color2 == null)) {
throw new NullPointerException("Colors cannot be null");
}
p1 = new Point2D.Float(x1, y1);
p2 = new Point2D.Float(x2, y2);
this.color1 = color1;
this.color2 = color2;
}
/**
* Constructs a simple acyclic <code>GradientPaint</code> object.
* @param pt1 the first specified <code>Point</code> in user space
* @param color1 <code>Color</code> at the first specified
* <code>Point</code>
* @param pt2 the second specified <code>Point</code> in user space
* @param color2 <code>Color</code> at the second specified
* <code>Point</code>
* @throws NullPointerException if either one of colors or points
* is null
*/
public GradientPaint(Point2D pt1,
Color color1,
Point2D pt2,
Color color2) {
if ((color1 == null) || (color2 == null) ||
(pt1 == null) || (pt2 == null)) {
throw new NullPointerException("Colors and points should be non-null");
}
p1 = new Point2D.Float((float)pt1.getX(), (float)pt1.getY());
p2 = new Point2D.Float((float)pt2.getX(), (float)pt2.getY());
this.color1 = color1;
this.color2 = color2;
}
/**
* Constructs either a cyclic or acyclic <code>GradientPaint</code>
* object depending on the <code>boolean</code> parameter.
* @param x1 x coordinate of the first specified
* <code>Point</code> in user space
* @param y1 y coordinate of the first specified
* <code>Point</code> in user space
* @param color1 <code>Color</code> at the first specified
* <code>Point</code>
* @param x2 x coordinate of the second specified
* <code>Point</code> in user space
* @param y2 y coordinate of the second specified
* <code>Point</code> in user space
* @param color2 <code>Color</code> at the second specified
* <code>Point</code>
* @param cyclic <code>true</code> if the gradient pattern should cycle
* repeatedly between the two colors; <code>false</code> otherwise
*/
public GradientPaint(float x1,
float y1,
Color color1,
float x2,
float y2,
Color color2,
boolean cyclic) {
this (x1, y1, color1, x2, y2, color2);
this.cyclic = cyclic;
}
/**
* Constructs either a cyclic or acyclic <code>GradientPaint</code>
* object depending on the <code>boolean</code> parameter.
* @param pt1 the first specified <code>Point</code>
* in user space
* @param color1 <code>Color</code> at the first specified
* <code>Point</code>
* @param pt2 the second specified <code>Point</code>
* in user space
* @param color2 <code>Color</code> at the second specified
* <code>Point</code>
* @param cyclic <code>true</code> if the gradient pattern should cycle
* repeatedly between the two colors; <code>false</code> otherwise
* @throws NullPointerException if either one of colors or points
* is null
*/
public GradientPaint(Point2D pt1,
Color color1,
Point2D pt2,
Color color2,
boolean cyclic) {
this (pt1, color1, pt2, color2);
this.cyclic = cyclic;
}
/**
* Returns a copy of the point P1 that anchors the first color.
* @return a {@link Point2D} object that is a copy of the point
* that anchors the first color of this
* <code>GradientPaint</code>.
*/
public Point2D getPoint1() {
return new Point2D.Float(p1.x, p1.y);
}
/**
* Returns the color C1 anchored by the point P1.
* @return a <code>Color</code> object that is the color
* anchored by P1.
*/
public Color getColor1() {
return color1;
}
/**
* Returns a copy of the point P2 which anchors the second color.
* @return a {@link Point2D} object that is a copy of the point
* that anchors the second color of this
* <code>GradientPaint</code>.
*/
public Point2D getPoint2() {
return new Point2D.Float(p2.x, p2.y);
}
/**
* Returns the color C2 anchored by the point P2.
* @return a <code>Color</code> object that is the color
* anchored by P2.
*/
public Color getColor2() {
return color2;
}
/**
* Returns <code>true</code> if the gradient cycles repeatedly
* between the two colors C1 and C2.
* @return <code>true</code> if the gradient cycles repeatedly
* between the two colors; <code>false</code> otherwise.
*/
public boolean isCyclic() {
return cyclic;
}
/**
* Creates and returns a context used to generate the color pattern.
* @param cm {@link ColorModel} that receives
* the <code>Paint</code> 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 xform 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.
* @see PaintContext
*/
public PaintContext createContext(ColorModel cm,
Rectangle deviceBounds,
Rectangle2D userBounds,
AffineTransform xform,
RenderingHints hints) {
return new GradientPaintContext(cm, p1, p2, xform,
color1, color2, cyclic);
}
/**
* Returns the transparency mode for this <code>GradientPaint</code>.
* @return an integer value representing this <code>GradientPaint</code>
* object's transparency mode.
* @see Transparency
*/
public int getTransparency() {
int a1 = color1.getAlpha();
int a2 = color2.getAlpha();
return (((a1 & a2) == 0xff) ? OPAQUE : TRANSLUCENT);
}
}
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