1 /*
2 * Copyright (c) 2011, 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.layout;
27
28 import com.sun.javafx.scene.layout.PaneHelper;
29 import javafx.beans.DefaultProperty;
30 import javafx.collections.ObservableList;
31 import javafx.scene.Node;
32
33 /**
34 * Base class for layout panes which need to expose the children list as public
35 * so that users of the subclass can freely add/remove children.
36 * <p>
37 * This class may be used directly in cases where absolute positioning of children
38 * is required since it does not perform layout beyond resizing resizable children
39 * to their preferred sizes. It is the application's responsibility to position the
40 * children since the pane leaves the positions alone during layout.
41 * For example:
42 * <pre>{@code
43 * Pane canvas = new Pane();
44 * canvas.setStyle("-fx-background-color: black;");
45 * canvas.setPrefSize(200,200);
46 * Circle circle = new Circle(50,Color.BLUE);
47 * circle.relocate(20, 20);
48 * Rectangle rectangle = new Rectangle(100,100,Color.RED);
49 * rectangle.relocate(70,70);
50 * canvas.getChildren().addAll(circle,rectangle);
51 * }</pre>
52 * <p>
53 * Note: if an application needs children to be kept aligned within a parent (centered,
54 * positioned at top-left, etc), it should use a {@link javafx.scene.layout.StackPane StackPane}
55 * instead.</p>
56 *
57 * <p>
58 * Pane resizes each managed child regardless of the child's visible property value;
59 * unmanaged children are ignored for all layout calculations.</p>
60 *
61 * <h3>Resizable Range</h3>
62 *
63 * <p>
64 * A pane's parent will resize the pane within the pane's resizable range
65 * during layout. By default the pane computes this range based on its content
66 * as outlined in the table below:
67 * </p>
68 *
69 * <table border="1">
70 * <caption>Pane Resize Table</caption>
71 * <tr><td></td><th scope="col">width</th><th scope="col">height</th></tr>
72 * <tr><th scope="row">minimum</th>
73 * <td>left plus right insets.</td>
74 * <td>top plus bottom insets.</td></tr>
75 * <tr><th scope="row">preferred</th>
76 * <td>width required to encompass each child at its current x location and preferred width.</td>
77 * <td>height required to encompass each child at its current y location and preferred height.</td></tr>
78 * <tr><th scope="row">maximum</th>
79 * <td>Double.MAX_VALUE</td><td>Double.MAX_VALUE</td></tr>
80 * </table>
81 * <p>
82 * A pane's unbounded maximum width and height are an indication to the parent that
83 * it may be resized beyond its preferred size to fill whatever space is assigned to it.
84 * <p>
85 * Pane provides properties for setting the size range directly. These
86 * properties default to the sentinel value Region.USE_COMPUTED_SIZE, however the
87 * application may set them to other values as needed:
88 * <pre><code>
89 * <b>pane.setPrefSize(500,400);</b>
90 * </code></pre>
91 * Applications may restore the computed values by setting these properties back
92 * to Region.USE_COMPUTED_SIZE.
93 * <p>
94 * Pane does not clip its content by default, so it is possible that children's
95 * bounds may extend outside its own bounds, either if children are positioned
96 * at negative coordinates or the pane is resized smaller than its preferred size.</p>
97 *
98 * @since JavaFX 2.0
99 */
100 @DefaultProperty("children")
101 public class Pane extends Region {
102 static {
103 PaneHelper.setPaneAccessor(new PaneHelper.PaneAccessor() {
104 });
105 }
106
107 static void setConstraint(Node node, Object key, Object value) {
108 if (value == null) {
109 node.getProperties().remove(key);
110 } else {
111 node.getProperties().put(key, value);
112 }
113 if (node.getParent() != null) {
114 node.getParent().requestLayout();
115 }
116 }
117
118 static Object getConstraint(Node node, Object key) {
119 if (node.hasProperties()) {
120 Object value = node.getProperties().get(key);
121 if (value != null) {
122 return value;
123 }
124 }
125 return null;
126 }
127
128 {
129 // To initialize the class helper at the begining each constructor of this class
130 PaneHelper.initHelper(this);
131 }
132 /**
133 * Creates a Pane layout.
134 */
135 public Pane() {
136 super();
137 }
138
139 /**
140 * Creates a Pane layout.
141 * @param children The initial set of children for this pane.
142 * @since JavaFX 8.0
143 */
144 public Pane(Node... children) {
145 super();
146 getChildren().addAll(children);
147 }
148
149 /**
150 *
151 * @return modifiable list of children.
152 */
153 @Override public ObservableList<Node> getChildren() {
154 return super.getChildren();
155 }
156
157 }