1 /*
2 * Copyright (c) 2010, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javafx.scene;
27
28 import com.sun.javafx.scene.GroupHelper;
29 import javafx.beans.DefaultProperty;
30 import javafx.beans.property.BooleanProperty;
31 import javafx.beans.property.BooleanPropertyBase;
32 import javafx.collections.ObservableList;
33 import javafx.geometry.Bounds;
34 import java.util.Collection;
35
36
37
38 /**
39 * A {@code Group} node contains an ObservableList of children that
40 * are rendered in order whenever this node is rendered.
41 * <p>
42 * A {@code Group} will take on the collective bounds of its children and is
43 * not directly resizable.
44 * <p>
45 * Any transform, effect, or state applied to a {@code Group} will be applied
46 * to all children of that group. Such transforms and effects will NOT be included
47 * in this Group's layout bounds, however if transforms and effects are set
48 * directly on children of this Group, those will be included in this Group's layout bounds.
49 * <p>
50 * By default, a {@code Group} will "auto-size" its managed resizable
51 * children to their preferred sizes during the layout pass to ensure that Regions
52 * and Controls are sized properly as their state changes. If an application
53 * needs to disable this auto-sizing behavior, then it should set
54 * {@link #autoSizeChildrenProperty() autoSizeChildren} to {@code false} and understand that if the preferred size of
55 * the children change, they will not automatically resize (so buyer beware!).
56 *
57 * <p>Group Example:</p>
58 *
59 <PRE>
60 import javafx.scene.*;
61 import javafx.scene.paint.*;
62 import javafx.scene.shape.*;
63 import java.lang.Math;
64
65 Group g = new Group();
66 for (int i = 0; i < 5; i++) {
67 Rectangle r = new Rectangle();
68 r.setY(i * 20);
69 r.setWidth(100);
70 r.setHeight(10);
71 r.setFill(Color.RED);
72 g.getChildren().add(r);
73 }
74 </PRE>
75 * @since JavaFX 2.0
76 */
77 @DefaultProperty("children")
78 public class Group extends Parent {
79 static {
80 // This is used by classes in different packages to get access to
81 // private and package private methods.
82 GroupHelper.setGroupAccessor(new GroupHelper.GroupAccessor() {
83 @Override
84 public Bounds doComputeLayoutBounds(Node node) {
85 return ((Group) node).doComputeLayoutBounds();
86 }
87 });
88 }
89
90 {
91 // To initialize the class helper at the begining each constructor of this class
92 GroupHelper.initHelper(this);
93 }
94
95 /**
96 * Constructs a group.
97 */
98 public Group() { }
99
100 /**
101 * Constructs a group consisting of children.
102 *
103 * @param children children.
104 */
105 public Group(Node... children) {
106 getChildren().addAll(children);
107 }
108
109 /**
110 * Constructs a group consisting of the given children.
111 *
112 * @param children children of the group
113 * @throws NullPointerException if the specified collection is null
114 * @since JavaFX 8.0
115 */
116 public Group(Collection<Node> children) {
117 getChildren().addAll(children);
118 }
119
120 /**
121 * Controls whether or not this {@code Group} will automatically resize any
122 * managed resizable children to their preferred sizes
123 * during the layout pass. If set to {@code false}, then the application is
124 * responsible for setting the size of this Group's resizable children, otherwise
125 * such nodes may end up with a zero width/height and will not be visible.
126 * This variable has no effect on content nodes which are not resizable (Shape, Text, etc).
127 *
128 * @defaultValue true
129 */
130 private BooleanProperty autoSizeChildren;
131
132
133 public final void setAutoSizeChildren(boolean value){
134 autoSizeChildrenProperty().set(value);
135 }
136
137 public final boolean isAutoSizeChildren() {
138 return autoSizeChildren == null ? true : autoSizeChildren.get();
139 }
140
141 public final BooleanProperty autoSizeChildrenProperty() {
142 if (autoSizeChildren == null) {
143 autoSizeChildren = new BooleanPropertyBase(true) {
144
145 @Override
146 protected void invalidated() {
147 requestLayout();
148 }
149
150 @Override
151 public Object getBean() {
152 return Group.this;
153 }
154
155 @Override
156 public String getName() {
157 return "autoSizeChildren";
158 }
159 };
160 }
161 return autoSizeChildren;
162 }
163
164 /**
165 * Gets the list of children of this {@code Group}.
166 * @return the list of children of this {@code Group}.
167 */
168 @Override public ObservableList<Node> getChildren() {
169 return super.getChildren();
170 }
171
172 /*
173 * Note: This method MUST only be called via its accessor method.
174 */
175 private Bounds doComputeLayoutBounds() {
176 layout(); // Needs to done prematurely, as we otherwise don't know the bounds of the children
177 return null; // helper only requires this node to call layout().
178 }
179
180 /**
181 * Group defines the preferred width as simply being the width of its layout bounds, which
182 * in turn is simply the sum of the positions and widths of all of its children. That is,
183 * the preferred width is the one that it is at, because a Group cannot be resized.
184 *
185 * Note: as the layout bounds in autosize Group depend on the Group to be already laid-out,
186 * this call will do the layout of the Group if necessary.
187 *
188 * @param height This parameter is ignored by Group
189 * @return The layout bounds width
190 */
191 @Override
192 public double prefWidth(double height) {
193 if (isAutoSizeChildren()) {
194 layout();
195 }
196 final double result = getLayoutBounds().getWidth();
197 return Double.isNaN(result) || result < 0 ? 0 : result;
198 }
199
200 /**
201 * Group defines the preferred height as simply being the height of its layout bounds, which
202 * in turn is simply the sum of the positions and heights of all of its children. That is,
203 * the preferred height is the one that it is at, because a Group cannot be resized.
204 *
205 * Note: as the layout bounds in autosize Group depend on the Group to be already laid-out,
206 * this call will do the layout of the Group if necessary.
207 *
208 * @param width This parameter is ignored by Group
209 * @return The layout bounds height
210 */
211 @Override
212 public double prefHeight(double width) {
213 if (isAutoSizeChildren()) {
214 layout();
215 }
216 final double result = getLayoutBounds().getHeight();
217 return Double.isNaN(result) || result < 0 ? 0 : result;
218 }
219
220
221 @Override
222 public double minHeight(double width) {
223 return prefHeight(width);
224 }
225
226 @Override
227 public double minWidth(double height) {
228 return prefWidth(height);
229 }
230
231 /**
232 * Group implements layoutChildren such that each child is resized to its preferred
233 * size, if the child is resizable. Non-resizable children are simply left alone.
234 * If {@link #autoSizeChildrenProperty() autoSizeChildren} is false, then Group does nothing in this method.
235 */
236 @Override protected void layoutChildren() {
237 if (isAutoSizeChildren()) {
238 super.layoutChildren();
239 }
240 }
241 }