Java tutorial
/* * Copyright (c) 2010, 2017, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javafx.scene.paint; import java.util.List; import com.sun.javafx.scene.paint.GradientUtils; import com.sun.javafx.tk.Toolkit; import javafx.beans.NamedArg; /** * The {@code RadialGradient} 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. * <p> * The user must specify the circle controlling the gradient pattern, * which is defined 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. * <p> * The center and radius are specified * relative to a unit square, unless the <code>proportional</code> * variable is false. By default proportional is true, and the * gradient will be scaled to fill whatever shape it is applied to. * The focus point is always specified relative to the center point * by an angle and a distance relative to the radius. * <p> * 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 of the gradient colors. * <p> * The focus distance will be clamped to the range {@code (-1, 1)} * so that the focus point is always strictly inside the circle. * <p> * The application provides an array of {@code Stop}s specifying how to distribute * the colors along the gradient. The {@code Stop#offset} variable must be * the range 0.0 to 1.0 and act like keyframes along the gradient. * They mark where the gradient should be exactly a particular color. * @since JavaFX 2.0 */ public final class RadialGradient extends Paint { private double focusAngle; /** * Defines the angle in degrees from the center of the gradient * to the focus point to which the first color is mapped. * @return the angle in degrees from the center of the gradient * to the focus point to which the first color is mapped */ public final double getFocusAngle() { return focusAngle; } private double focusDistance; /** * Defines the distance from the center of the gradient to the * focus point to which the first color is mapped. * A distance of 0.0 will be at the center of the gradient circle. * A distance of 1.0 will be on the circumference of the gradient circle. * @return the distance from the center of the gradient to the * focus point to which the first color is mapped */ public final double getFocusDistance() { return focusDistance; } private double centerX; /** * Defines the X coordinate of the center point of the circle defining the gradient. * If proportional is true (the default), this value specifies a * point on a unit square that will be scaled to match the size of the * the shape that the gradient fills. * The last color of the gradient is mapped to the perimeter of this circle. * * @return the X coordinate of the center point of the circle defining the * gradient * @defaultValue 0.0 */ public final double getCenterX() { return centerX; } private double centerY; /** * Defines the X coordinate of the center point of the circle defining the gradient. * If proportional is true (the default), this value specifies a * point on a unit square that will be scaled to match the size of the * the shape that the gradient fills. * The last color of the gradient is mapped to the perimeter of this circle. * * @return the X coordinate of the center point of the circle defining the * gradient * @defaultValue 0.0 */ public final double getCenterY() { return centerY; } private double radius; /** * Specifies the radius of the circle defining the extents of the color gradient. * If proportional is true (the default), this value specifies a * size relative to unit square that will be scaled to match the size of the * the shape that the gradient fills. * * @return the radius of the circle defining the extents of the color * gradient * @defaultValue 1.0 */ public final double getRadius() { return radius; } private boolean proportional; /** * Indicates whether the center and radius values are proportional or * absolute. * If this flag is true, the center point and radius are defined * in a coordinate space where coordinates in the range {@code [0..1]} * are scaled to map onto the bounds of the shape that the gradient fills. * If this flag is false, then the center coordinates and the radius are * specified in the local coordinate system of the node. * * @return true if the center and radius values are proportional, otherwise * absolute * @defaultValue true */ public final boolean isProportional() { return proportional; } private CycleMethod cycleMethod; /** * Defines the cycle method applied * to the {@code RadialGradient}. One of: {@code CycleMethod.NO_CYCLE}, * {@code CycleMethod.REFLECT}, or {@code CycleMethod.REPEAT}. * * @return the cycle method applied to this radial gradient * @defaultValue NO_CYCLE */ public final CycleMethod getCycleMethod() { return cycleMethod; } private List<Stop> stops; /** * A sequence of 2 or more {@code Stop} values specifying how to distribute * the colors along the gradient. These values must be in the range * 0.0 to 1.0. They act like keyframes along the gradient: they mark where the * gradient should be exactly a particular color. * * <p>Each stop in the sequence must have an offset that is greater than the previous * stop in the sequence.</p> * * <p>The list is unmodifiable and will throw * {@code UnsupportedOperationException} on each modification attempt.</p> * * @return the list of Stop values * @defaultValue empty */ public final List<Stop> getStops() { return stops; } /** * {@inheritDoc} * @since JavaFX 8.0 */ @Override public final boolean isOpaque() { return opaque; } private final boolean opaque; /** * A cached reference to the platform paint, no point recomputing twice */ private Object platformPaint; /** * The cached hash code, used to improve performance in situations where * we cache gradients, such as in the CSS routines. */ private int hash; /** * Creates a new instance of RadialGradient. * @param focusAngle the angle in degrees from the center of the gradient * to the focus point to which the first color is mapped * @param focusDistance the distance from the center of the gradient to the * focus point to which the first color is mapped * @param centerX the X coordinate of the center point of the gradient's circle * @param centerY the Y coordinate of the center point of the gradient's circle * @param radius the radius of the circle defining the extents of the color gradient * @param proportional whether the coordinates and sizes are proportional * to the shape which this gradient fills * @param cycleMethod cycle method applied to the gradient * @param stops the gradient's color specification */ public RadialGradient(@NamedArg("focusAngle") double focusAngle, @NamedArg("focusDistance") double focusDistance, @NamedArg("centerX") double centerX, @NamedArg("centerY") double centerY, @NamedArg(value = "radius", defaultValue = "1") double radius, @NamedArg(value = "proportional", defaultValue = "true") boolean proportional, @NamedArg("cycleMethod") CycleMethod cycleMethod, @NamedArg("stops") Stop... stops) { this.focusAngle = focusAngle; this.focusDistance = focusDistance; this.centerX = centerX; this.centerY = centerY; this.radius = radius; this.proportional = proportional; this.cycleMethod = (cycleMethod == null) ? CycleMethod.NO_CYCLE : cycleMethod; this.stops = Stop.normalize(stops); this.opaque = determineOpacity(); } /** * Creates a new instance of RadialGradient. * @param focusAngle the angle in degrees from the center of the gradient * to the focus point to which the first color is mapped * @param focusDistance the distance from the center of the gradient to the * focus point to which the first color is mapped * @param centerX the X coordinate of the center point of the gradient's circle * @param centerY the Y coordinate of the center point of the gradient's circle * @param radius the radius of the circle defining the extents of the color gradient * @param proportional whether the coordinates and sizes are proportional * to the shape which this gradient fills * @param cycleMethod cycle method applied to the gradient * @param stops the gradient's color specification */ public RadialGradient(@NamedArg("focusAngle") double focusAngle, @NamedArg("focusDistance") double focusDistance, @NamedArg("centerX") double centerX, @NamedArg("centerY") double centerY, @NamedArg(value = "radius", defaultValue = "1") double radius, @NamedArg(value = "proportional", defaultValue = "true") boolean proportional, @NamedArg("cycleMethod") CycleMethod cycleMethod, @NamedArg("stops") List<Stop> stops) { this.focusAngle = focusAngle; this.focusDistance = focusDistance; this.centerX = centerX; this.centerY = centerY; this.radius = radius; this.proportional = proportional; this.cycleMethod = (cycleMethod == null) ? CycleMethod.NO_CYCLE : cycleMethod; this.stops = Stop.normalize(stops); this.opaque = determineOpacity(); } /** * Iterate over all the stops. If any one of them has a transparent * color, then we return false. If there are no stops, we return false. * Otherwise, we return true. Note that this is called AFTER Stop.normalize, * which ensures that we always have at least 2 stops. * * @return Whether this gradient is opaque */ private boolean determineOpacity() { final int numStops = this.stops.size(); for (int i = 0; i < numStops; i++) { if (!stops.get(i).getColor().isOpaque()) { return false; } } return true; } @Override Object acc_getPlatformPaint() { if (platformPaint == null) { platformPaint = Toolkit.getToolkit().getPaint(this); } return platformPaint; } /** * Indicates whether some other object is "equal to" this one. * @param obj the reference object with which to compare. * @return {@code true} if this object is equal to the {@code obj} argument; {@code false} otherwise. */ @Override public boolean equals(Object obj) { if (obj == this) return true; if (obj instanceof RadialGradient) { final RadialGradient other = (RadialGradient) obj; if ((focusAngle != other.focusAngle) || (focusDistance != other.focusDistance) || (centerX != other.centerX) || (centerY != other.centerY) || (radius != other.radius) || (proportional != other.proportional) || (cycleMethod != other.cycleMethod)) return false; if (!stops.equals(other.stops)) return false; return true; } else return false; } /** * Returns a hash code for this {@code RadialGradient} object. * @return a hash code for this {@code RadialGradient} object. */ @Override public int hashCode() { // We should be able to just call focusAngle.hashCode(), // see http://javafx-jira.kenai.com/browse/JFXC-4247 if (hash == 0) { long bits = 17; bits = 37 * bits + Double.doubleToLongBits(focusAngle); bits = 37 * bits + Double.doubleToLongBits(focusDistance); bits = 37 * bits + Double.doubleToLongBits(centerX); bits = 37 * bits + Double.doubleToLongBits(centerY); bits = 37 * bits + Double.doubleToLongBits(radius); bits = 37 * bits + (proportional ? 1231 : 1237); bits = 37 * bits + cycleMethod.hashCode(); for (Stop stop : stops) { bits = 37 * bits + stop.hashCode(); } hash = (int) (bits ^ (bits >> 32)); } return hash; } /** * Returns a string representation of this {@code RadialGradient} object. * @return a string representation of this {@code RadialGradient} object. */ @Override public String toString() { final StringBuilder s = new StringBuilder("radial-gradient(focus-angle ").append(focusAngle) .append("deg, focus-distance ").append(focusDistance * 100).append("% , center ") .append(GradientUtils.lengthToString(centerX, proportional)).append(" ") .append(GradientUtils.lengthToString(centerY, proportional)).append(", radius ") .append(GradientUtils.lengthToString(radius, proportional)).append(", "); switch (cycleMethod) { case REFLECT: s.append("reflect").append(", "); break; case REPEAT: s.append("repeat").append(", "); break; } for (Stop stop : stops) { s.append(stop).append(", "); } s.delete(s.length() - 2, s.length()); s.append(")"); return s.toString(); } /** * Creates a radial gradient value from a string representation. * <p>The format of the string representation is based on * JavaFX CSS specification for radial gradient which is * <pre> * radial-gradient([focus-angle <angle>, ]? * [focus-distance <percentage>, ]? * [center <point>, ]? * radius [<length> | <percentage>], * [[repeat | reflect],]? * <color-stop>[, <color-stop>]+) * </pre> * where * <pre> * <point> = [ [ <length> <length> ] | [ <percentage> | <percentage> ] ] * <color-stop> = [ <color> [ <percentage> | <length>]? ] * </pre> * <p>Currently length can be only specified in px, the specification of unit can be omited. * Format of color representation is the one used in {@link Color#web(String color)}. * The radial-gradient keyword can be omited. * For additional information about the format of string representation, see the * <a href="../doc-files/cssref.html">CSS Reference Guide</a>. * </p> * * Examples: * <pre>{@code * RadialGradient g * = RadialGradient.valueOf("radial-gradient(center 100px 100px, radius 200px, red 0%, blue 30%, black 100%)"); * RadialGradient g * = RadialGradient.valueOf("center 100px 100px, radius 200px, red 0%, blue 30%, black 100%"); * RadialGradient g * = RadialGradient.valueOf("radial-gradient(center 50% 50%, radius 50%, cyan, violet 75%, magenta)"); * RadialGradient g * = RadialGradient.valueOf("center 50% 50%, radius 50%, cyan, violet 75%, magenta"); * }</pre> * * @param value the string to convert * @throws NullPointerException if the {@code value} is {@code null} * @throws IllegalArgumentException if the {@code value} cannot be parsed * @return a {@code RadialGradient} object holding the value represented * by the string argument. * @since JavaFX 2.1 */ public static RadialGradient valueOf(String value) { if (value == null) { throw new NullPointerException("gradient must be specified"); } String start = "radial-gradient("; String end = ")"; if (value.startsWith(start)) { if (!value.endsWith(end)) { throw new IllegalArgumentException( "Invalid gradient specification," + " must end with \"" + end + '"'); } value = value.substring(start.length(), value.length() - end.length()); } GradientUtils.Parser parser = new GradientUtils.Parser(value); if (parser.getSize() < 2) { throw new IllegalArgumentException("Invalid gradient specification"); } double angle = 0, distance = 0; GradientUtils.Point centerX, centerY, radius; String[] tokens = parser.splitCurrentToken(); if ("focus-angle".equals(tokens[0])) { GradientUtils.Parser.checkNumberOfArguments(tokens, 1); angle = GradientUtils.Parser.parseAngle(tokens[1]); parser.shift(); } tokens = parser.splitCurrentToken(); if ("focus-distance".equals(tokens[0])) { GradientUtils.Parser.checkNumberOfArguments(tokens, 1); distance = GradientUtils.Parser.parsePercentage(tokens[1]); parser.shift(); } tokens = parser.splitCurrentToken(); if ("center".equals(tokens[0])) { GradientUtils.Parser.checkNumberOfArguments(tokens, 2); centerX = parser.parsePoint(tokens[1]); centerY = parser.parsePoint(tokens[2]); parser.shift(); } else { centerX = GradientUtils.Point.MIN; centerY = GradientUtils.Point.MIN; } tokens = parser.splitCurrentToken(); if ("radius".equals(tokens[0])) { GradientUtils.Parser.checkNumberOfArguments(tokens, 1); radius = parser.parsePoint(tokens[1]); parser.shift(); } else { throw new IllegalArgumentException("Invalid gradient specification: " + "radius must be specified"); } CycleMethod method = CycleMethod.NO_CYCLE; String currentToken = parser.getCurrentToken(); if ("repeat".equals(currentToken)) { method = CycleMethod.REPEAT; parser.shift(); } else if ("reflect".equals(currentToken)) { method = CycleMethod.REFLECT; parser.shift(); } Stop[] stops = parser.parseStops(radius.proportional, radius.value); return new RadialGradient(angle, distance, centerX.value, centerY.value, radius.value, radius.proportional, method, stops); } }