org.openjfx/javafx-graphics/14 : javafx/scene/layout/VBox.java

VBox
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/*
 * Copyright (c) 2011, 2019, 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
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 * questions.
 */

package javafx.scene.layout;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javafx.beans.property.BooleanProperty;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.ObjectProperty;
import javafx.css.CssMetaData;
import javafx.css.StyleableBooleanProperty;
import javafx.css.StyleableDoubleProperty;
import javafx.css.StyleableObjectProperty;
import javafx.css.StyleableProperty;
import javafx.geometry.HPos;
import javafx.geometry.Insets;
import javafx.geometry.Orientation;
import javafx.geometry.Pos;
import javafx.geometry.VPos;
import javafx.scene.Node;
import javafx.css.converter.BooleanConverter;
import javafx.css.converter.EnumConverter;
import javafx.css.converter.SizeConverter;
import javafx.css.Styleable;
import javafx.util.Callback;

VBox lays out its children in a single vertical column.
If the vbox has a border and/or padding set, then the contents will be laid
out within those insets.

VBox example:

    VBox vbox = new VBox(8); // spacing = 8
    vbox.getChildren().addAll(new Button("Cut"), new Button("Copy"), new Button("Paste"));
 VBox will resize children (if resizable) to their preferred heights and uses its fillWidth property to determine whether to resize their widths to fill its own width or keep their widths to their preferred (fillWidth defaults to true). The alignment of the content is controlled by the alignment property, which defaults to Pos.TOP_LEFT. 
If a vbox is resized larger than its preferred height, by default it will keep
children to their preferred heights, leaving the extra space unused.  If an
application wishes to have one or more children be allocated that extra space
it may optionally set a vgrow constraint on the child.  See "Optional Layout
Constraints" for details.

VBox lays out each managed child regardless of the child's
visible property value; unmanaged children are ignored.
Resizable Range

A vbox's parent will resize the vbox within the vbox's resizable range
during layout.   By default the vbox computes this range based on its content
as outlined in the table below.


VBox Resize Table
width height
minimum
left/right insets plus the largest of the children's min widths.
top/bottom insets plus the sum of each child's min height plus spacing between each child.

preferred
left/right insets plus the largest of the children's pref widths.
top/bottom insets plus the sum of each child's pref height plus spacing between each child.

maximum
Double.MAX_VALUE Double.MAX_VALUE


A vbox's unbounded maximum width and height are an indication to the parent that
it may be resized beyond its preferred size to fill whatever space is assigned
to it.

VBox provides properties for setting the size range directly.  These
properties default to the sentinel value USE_COMPUTED_SIZE, however the
application may set them to other values as needed:

    vbox.setPrefWidth(400);

Applications may restore the computed values by setting these properties back
to USE_COMPUTED_SIZE.

VBox does not clip its content by default, so it is possible that children's
bounds may extend outside its own bounds if a child's min size prevents it from
being fit within the vbox.
Optional Layout Constraints

An application may set constraints on individual children to customize VBox's layout.
For each constraint, VBox provides a static method for setting it on the child.


VBox Constraint Table
Constraint Type Description
vgrow javafx.scene.layout.Priority The vertical grow priority for the child.
margin javafx.geometry.Insets Margin space around the outside of the child.


For example, if a vbox needs the ListView to be allocated all extra space:

    VBox vbox = new VBox();
    ListView list = new ListView();
    VBox.setVgrow(list, Priority.ALWAYS);
    vbox.getChildren().addAll(new Label("Names:"), list);

If more than one child has the same grow priority set, then the vbox will
allocate equal amounts of space to each.  VBox will only grow a child up to
its maximum height, so if the child has a max height other than Double.MAX_VALUE,
the application may need to override the max to allow it to grow.
Since: JavaFX 2.0/**
 * VBox lays out its children in a single vertical column.
 * If the vbox has a border and/or padding set, then the contents will be laid
 * out within those insets.
 * <p>
 * VBox example:
 * <pre>{@code
 *     VBox vbox = new VBox(8); // spacing = 8
 *     vbox.getChildren().addAll(new Button("Cut"), new Button("Copy"), new Button("Paste"));
 * }</pre>
 *
 * VBox will resize children (if resizable) to their preferred heights and uses its
 * {@link #fillWidthProperty() fillWidth} property to determine whether to resize their widths to
 * fill its own width or keep their widths to their preferred (fillWidth defaults to true).
 * The alignment of the content is controlled by the {@link #alignmentProperty() alignment} property,
 * which defaults to Pos.TOP_LEFT.
 * <p>
 * If a vbox is resized larger than its preferred height, by default it will keep
 * children to their preferred heights, leaving the extra space unused.  If an
 * application wishes to have one or more children be allocated that extra space
 * it may optionally set a vgrow constraint on the child.  See "Optional Layout
 * Constraints" for details.
 * <p>
 * VBox lays out each managed child regardless of the child's
 * visible property value; unmanaged children are ignored.</p>
 *
 * <h2>Resizable Range</h2>
 *
 * <p>
 * A vbox's parent will resize the vbox within the vbox's resizable range
 * during layout.   By default the vbox computes this range based on its content
 * as outlined in the table below.
 * </p>
 * <table border="1">
 * <caption>VBox Resize Table</caption>
 * <tr><td></td><th scope="col">width</th><th scope="col">height</th></tr>
 * <tr><th scope="row">minimum</th>
 * <td>left/right insets plus the largest of the children's min widths.</td>
 * <td>top/bottom insets plus the sum of each child's min height plus spacing between each child.</td>
 * </tr>
 * <tr><th scope="row">preferred</th>
 * <td>left/right insets plus the largest of the children's pref widths.</td>
 * <td>top/bottom insets plus the sum of each child's pref height plus spacing between each child.</td>
 * </tr>
 * <tr><th scope="row">maximum</th>
 * <td>Double.MAX_VALUE</td><td>Double.MAX_VALUE</td></tr>
 * </table>
 * <p>
 * A vbox's unbounded maximum width and height are an indication to the parent that
 * it may be resized beyond its preferred size to fill whatever space is assigned
 * to it.
 * <p>
 * VBox provides properties for setting the size range directly.  These
 * properties default to the sentinel value USE_COMPUTED_SIZE, however the
 * application may set them to other values as needed:
 * <pre><code>
 *     <b>vbox.setPrefWidth(400);</b>
 * </code></pre>
 * Applications may restore the computed values by setting these properties back
 * to USE_COMPUTED_SIZE.
 * <p>
 * VBox does not clip its content by default, so it is possible that children's
 * bounds may extend outside its own bounds if a child's min size prevents it from
 * being fit within the vbox.</p>
 *
 * <h2>Optional Layout Constraints</h2>
 *
 * <p>
 * An application may set constraints on individual children to customize VBox's layout.
 * For each constraint, VBox provides a static method for setting it on the child.
 * </p>
 *
 * <table border="1">
 * <caption>VBox Constraint Table</caption>
 * <tr><th scope="col">Constraint</th><th scope="col">Type</th><th scope="col">Description</th></tr>
 * <tr><th scope="row">vgrow</th><td>javafx.scene.layout.Priority</td><td>The vertical grow priority for the child.</td></tr>
 * <tr><th scope="row">margin</th><td>javafx.geometry.Insets</td><td>Margin space around the outside of the child.</td></tr>
 * </table>
 * <p>
 * For example, if a vbox needs the ListView to be allocated all extra space:
 * <pre><code>
 *     VBox vbox = new VBox();
 *     ListView list = new ListView();
 *     <b>VBox.setVgrow(list, Priority.ALWAYS);</b>
 *     vbox.getChildren().addAll(new Label("Names:"), list);
 * </code></pre>
 *
 * If more than one child has the same grow priority set, then the vbox will
 * allocate equal amounts of space to each.  VBox will only grow a child up to
 * its maximum height, so if the child has a max height other than Double.MAX_VALUE,
 * the application may need to override the max to allow it to grow.
 * @since JavaFX 2.0
 */
public class VBox extends Pane {

    private boolean biasDirty = true;
    private Orientation bias;
    private double[][] tempArray;

 BEGIN static methods
/********************************************************************
     *  BEGIN static methods
     ********************************************************************/
    private static final String MARGIN_CONSTRAINT = "vbox-margin";
    private static final String VGROW_CONSTRAINT = "vbox-vgrow";

    Sets the vertical grow priority for the child when contained by an vbox.
If set, the vbox will use the priority to allocate additional space if the
vbox is resized larger than it's preferred height.
If multiple vbox children have the same vertical grow priority, then the
extra space will be split evenly between them.
If no vertical grow priority is set on a child, the vbox will never
allocate it additional vertical space if available.
Setting the value to null will remove the constraint.
Params: child – the child of a vbox
value – the horizontal grow priority for the child/**
     * Sets the vertical grow priority for the child when contained by an vbox.
     * If set, the vbox will use the priority to allocate additional space if the
     * vbox is resized larger than it's preferred height.
     * If multiple vbox children have the same vertical grow priority, then the
     * extra space will be split evenly between them.
     * If no vertical grow priority is set on a child, the vbox will never
     * allocate it additional vertical space if available.
     * Setting the value to null will remove the constraint.
     * @param child the child of a vbox
     * @param value the horizontal grow priority for the child
     */
    public static void setVgrow(Node child, Priority value) {
        setConstraint(child, VGROW_CONSTRAINT, value);
    }

    Returns the child's vgrow property if set.
Params: child – the child node of a vbox
Returns: the vertical grow priority for the child or null if no priority was set/**
     * Returns the child's vgrow property if set.
     * @param child the child node of a vbox
     * @return the vertical grow priority for the child or null if no priority was set
     */
    public static Priority getVgrow(Node child) {
        return (Priority)getConstraint(child, VGROW_CONSTRAINT);
    }

    Sets the margin for the child when contained by a vbox.
If set, the vbox will layout the child so that it has the margin space around it.
Setting the value to null will remove the constraint.
Params: child – the child mode of a vbox
value – the margin of space around the child/**
     * Sets the margin for the child when contained by a vbox.
     * If set, the vbox will layout the child so that it has the margin space around it.
     * Setting the value to null will remove the constraint.
     * @param child the child mode of a vbox
     * @param value the margin of space around the child
     */
    public static void setMargin(Node child, Insets value) {
        setConstraint(child, MARGIN_CONSTRAINT, value);
    }

    Returns the child's margin property if set.
Params: child – the child node of a vbox
Returns: the margin for the child or null if no margin was set/**
     * Returns the child's margin property if set.
     * @param child the child node of a vbox
     * @return the margin for the child or null if no margin was set
     */
    public static Insets getMargin(Node child) {
        return (Insets)getConstraint(child, MARGIN_CONSTRAINT);
    }

    private static final Callback<Node, Insets> marginAccessor = n -> getMargin(n);

    Removes all vbox constraints from the child node.
Params: child – the child node/**
     * Removes all vbox constraints from the child node.
     * @param child the child node
     */
    public static void clearConstraints(Node child) {
        setVgrow(child, null);
        setMargin(child, null);
    }

    /********************************************************************
     *  END static methods
     ********************************************************************/

    Creates a VBox layout with spacing = 0 and alignment at TOP_LEFT.
/**
     * Creates a VBox layout with spacing = 0 and alignment at TOP_LEFT.
     */
    public VBox() {
        super();
    }

    Creates a VBox layout with the specified spacing between children.
Params: spacing – the amount of vertical space between each child/**
     * Creates a VBox layout with the specified spacing between children.
     * @param spacing the amount of vertical space between each child
     */
    public VBox(double spacing) {
        this();
        setSpacing(spacing);
    }

    Creates an VBox layout with spacing = 0.
Params: children – The initial set of children for this pane.
Since: JavaFX 8.0/**
     * Creates an VBox layout with spacing = 0.
     * @param children The initial set of children for this pane.
     * @since JavaFX 8.0
     */
    public VBox(Node... children) {
        super();
        getChildren().addAll(children);
    }

    Creates an VBox layout with the specified spacing between children.
Params: spacing – the amount of horizontal space between each child
children – The initial set of children for this pane.
Since: JavaFX 8.0/**
     * Creates an VBox layout with the specified spacing between children.
     * @param spacing the amount of horizontal space between each child
     * @param children The initial set of children for this pane.
     * @since JavaFX 8.0
     */
    public VBox(double spacing, Node... children) {
        this();
        setSpacing(spacing);
        getChildren().addAll(children);
    }

    The amount of vertical space between each child in the vbox.
Returns: the amount of vertical space between each child in the vbox/**
     * The amount of vertical space between each child in the vbox.
     * @return the amount of vertical space between each child in the vbox
     */
    public final DoubleProperty spacingProperty() {
        if (spacing == null) {
            spacing = new StyleableDoubleProperty() {
                @Override
                public void invalidated() {
                    requestLayout();
                }

                @Override
                public Object getBean() {
                    return VBox.this;
                }

                @Override
                public String getName() {
                    return "spacing";
                }

                @Override
                public CssMetaData<VBox, Number> getCssMetaData() {
                    return StyleableProperties.SPACING;
                }
            };
        }
        return spacing;
    }

    private DoubleProperty spacing;
    public final void setSpacing(double value) { spacingProperty().set(value); }
    public final double getSpacing() { return spacing == null ? 0 : spacing.get(); }

    The overall alignment of children within the vbox's width and height.
Returns: the overall alignment of children within the vbox's width and
height/**
     * The overall alignment of children within the vbox's width and height.
     * @return the overall alignment of children within the vbox's width and
     * height
     */
    public final ObjectProperty<Pos> alignmentProperty() {
        if (alignment == null) {
            alignment = new StyleableObjectProperty<Pos>(Pos.TOP_LEFT) {
                @Override
                public void invalidated() {
                    requestLayout();
                }

                @Override
                public Object getBean() {
                    return VBox.this;
                }

                @Override
                public String getName() {
                    return "alignment";
                }

                @Override
                public CssMetaData<VBox, Pos> getCssMetaData() {
                    return StyleableProperties.ALIGNMENT;
                }
            };
        }
        return alignment;
    }

    private ObjectProperty<Pos> alignment;
    public final void setAlignment(Pos value) { alignmentProperty().set(value); }
    public final Pos getAlignment() { return alignment == null ? Pos.TOP_LEFT : alignment.get(); }
    private Pos getAlignmentInternal() {
        Pos localPos = getAlignment();
        return localPos == null ? Pos.TOP_LEFT : localPos;
    }

    Whether or not resizable children will be resized to fill the full width of the vbox
or be resized to their preferred width and aligned according to the alignment
hpos value.
Returns: true if resizable children will be resized to fill the full width
of the vbox/**
     * Whether or not resizable children will be resized to fill the full width of the vbox
     * or be resized to their preferred width and aligned according to the <code>alignment</code>
     * hpos value.
     * @return true if resizable children will be resized to fill the full width
     * of the vbox
     */
    public final BooleanProperty fillWidthProperty() {
        if (fillWidth == null) {
            fillWidth = new StyleableBooleanProperty(true) {
                @Override
                public void invalidated() {
                    requestLayout();
                }

                @Override
                public Object getBean() {
                    return VBox.this;
                }

                @Override
                public String getName() {
                    return "fillWidth";
                }

                @Override
                public CssMetaData<VBox, Boolean> getCssMetaData() {
                    return StyleableProperties.FILL_WIDTH;
                }
            };
        }
        return fillWidth;
    }

    private BooleanProperty fillWidth;
    public final void setFillWidth(boolean value) { fillWidthProperty().set(value); }
    public final boolean isFillWidth() { return fillWidth == null ? true : fillWidth.get(); }

    Returns: null unless one of its children has a content bias./**
     *
     * @return null unless one of its children has a content bias.
     */
    @Override public Orientation getContentBias() {
        if (biasDirty) {
            bias = null;
            final List<Node> children = getManagedChildren();
            for (Node child : children) {
                Orientation contentBias = child.getContentBias();
                if (contentBias != null) {
                    bias = contentBias;
                    if (contentBias == Orientation.HORIZONTAL) {
                        break;
                    }
                }
            }
            biasDirty = false;
        }
        return bias;
    }

    @Override protected double computeMinWidth(double height) {
        Insets insets = getInsets();
        List<Node>managed = getManagedChildren();
        double contentWidth = 0;
        if (height != -1 && getContentBias() != null) {
            double prefHeights[][] = getAreaHeights(managed, -1, false);
            adjustAreaHeights(managed, prefHeights, height, -1);
            contentWidth = computeMaxMinAreaWidth(managed, marginAccessor, prefHeights[0], false);
        } else {
            contentWidth = computeMaxMinAreaWidth(managed, marginAccessor);
        }
        return snapSpaceX(insets.getLeft()) + contentWidth + snapSpaceX(insets.getRight());
    }

    @Override protected double computeMinHeight(double width) {
        Insets insets = getInsets();
        return snapSpaceY(insets.getTop()) +
               computeContentHeight(getManagedChildren(), width, true) +
               snapSpaceY(insets.getBottom());
    }

    @Override protected double computePrefWidth(double height) {
        Insets insets = getInsets();
        List<Node>managed = getManagedChildren();
        double contentWidth = 0;
        if (height != -1 && getContentBias() != null) {
            double prefHeights[][] = getAreaHeights(managed, -1, false);
            adjustAreaHeights(managed, prefHeights, height, -1);
            contentWidth = computeMaxPrefAreaWidth(managed, marginAccessor, prefHeights[0], false);
        } else {
            contentWidth = computeMaxPrefAreaWidth(managed, marginAccessor);
        }
        return snapSpaceX(insets.getLeft()) + contentWidth + snapSpaceX(insets.getRight());
    }

    @Override protected double computePrefHeight(double width) {
        Insets insets = getInsets();
        double d = snapSpaceY(insets.getTop()) +
               computeContentHeight(getManagedChildren(), width, false) +
               snapSpaceY(insets.getBottom());
        return d;
    }


    private double[][] getAreaHeights(List<Node>managed, double width, boolean minimum) {
        // width could be -1
        double[][] temp = getTempArray(managed.size());
        final double insideWidth = width == -1? -1 : width -
                                     snapSpaceX(getInsets().getLeft()) - snapSpaceX(getInsets().getRight());
        final boolean isFillWidth = isFillWidth();
        for (int i = 0, size = managed.size(); i < size; i++) {
            Node child = managed.get(i);
            Insets margin = getMargin(child);
            if (minimum) {
                if (insideWidth != -1 && isFillWidth) {
                    temp[0][i] = computeChildMinAreaHeight(child, -1, margin, insideWidth);
                } else {
                    temp[0][i] = computeChildMinAreaHeight(child, -1, margin, -1);
                }
            } else {
                if (insideWidth != -1 && isFillWidth) {
                    temp[0][i] = computeChildPrefAreaHeight(child, -1, margin, insideWidth);
                } else {
                    temp[0][i] = computeChildPrefAreaHeight(child, -1, margin, -1);
                }
            }
        }
        return temp;
    }

    private double adjustAreaHeights(List<Node>managed, double areaHeights[][], double height, double width) {
        Insets insets = getInsets();
        double left = snapSpaceX(insets.getLeft());
        double right = snapSpaceX(insets.getRight());

        double contentHeight = sum(areaHeights[0], managed.size()) + (managed.size()-1)*snapSpaceY(getSpacing());
        double extraHeight = height -
                snapSpaceY(insets.getTop()) - snapSpaceY(insets.getBottom()) - contentHeight;

        if (extraHeight != 0) {
            final double refWidth = isFillWidth()&& width != -1? width - left - right : -1;
            double remaining = growOrShrinkAreaHeights(managed, areaHeights, Priority.ALWAYS, extraHeight, refWidth);
            remaining = growOrShrinkAreaHeights(managed, areaHeights, Priority.SOMETIMES, remaining, refWidth);
            contentHeight += (extraHeight - remaining);
        }

        return contentHeight;
    }

    private double growOrShrinkAreaHeights(List<Node>managed, double areaHeights[][], Priority priority, double extraHeight, double width) {
        final boolean shrinking = extraHeight < 0;
        int adjustingNumber = 0;

        double[] usedHeights = areaHeights[0];
        double[] temp = areaHeights[1];

        if (shrinking) {
            adjustingNumber = managed.size();
            for (int i = 0, size = managed.size(); i < size; i++) {
                final Node child = managed.get(i);
                temp[i] = computeChildMinAreaHeight(child, -1, getMargin(child), width);
            }
        } else {
            for (int i = 0, size = managed.size(); i < size; i++) {
            final Node child = managed.get(i);
            if (getVgrow(child) == priority) {
                temp[i] = computeChildMaxAreaHeight(child, -1, getMargin(child), width);
                adjustingNumber++;
            } else {
                temp[i] = -1;
            }
        }
        }

        double available = extraHeight; // will be negative in shrinking case
        outer: while (Math.abs(available) > 1 && adjustingNumber > 0) {
            final double portion = snapPortionY(available / adjustingNumber); // negative in shrinking case
            for (int i = 0, size = managed.size(); i < size; i++) {
                if (temp[i] == -1) {
                    continue;
                }
                final double limit = temp[i] - usedHeights[i]; // negative in shrinking case
                final double change = Math.abs(limit) <= Math.abs(portion)? limit : portion;
                usedHeights[i] += change;
                available -= change;
                if (Math.abs(available) < 1) {
                    break outer;
                }
                if (Math.abs(change) < Math.abs(portion)) {
                    temp[i] = -1;
                    adjustingNumber--;
                }
            }
        }

        return available; // might be negative in shrinking case
    }

    private double computeContentHeight(List<Node> managedChildren, double width, boolean minimum) {
        return sum(getAreaHeights(managedChildren, width, minimum)[0], managedChildren.size())
                + (managedChildren.size()-1)*snapSpaceY(getSpacing());
    }

    private static double sum(double[] array, int size) {
        int i = 0;
        double res = 0;
        while (i != size) {
            res += array[i++];
        }
        return res;
    }

    @Override public void requestLayout() {
        biasDirty = true;
        bias = null;
        super.requestLayout();
    }

    @Override protected void layoutChildren() {
        List<Node> managed = getManagedChildren();
        Insets insets = getInsets();
        double width = getWidth();
        double height = getHeight();
        double top = snapSpaceY(insets.getTop());
        double left = snapSpaceX(insets.getLeft());
        double bottom = snapSpaceY(insets.getBottom());
        double right = snapSpaceX(insets.getRight());
        double space = snapSpaceY(getSpacing());
        HPos hpos = getAlignmentInternal().getHpos();
        VPos vpos = getAlignmentInternal().getVpos();
        boolean isFillWidth = isFillWidth();

        double[][] actualAreaHeights = getAreaHeights(managed, width, false);
        double contentWidth = width - left - right;
        double contentHeight = adjustAreaHeights(managed, actualAreaHeights, height, width);

        double x = left;
        double y = top + computeYOffset(height - top - bottom, contentHeight, vpos);

        for (int i = 0, size = managed.size(); i < size; i++) {
            Node child = managed.get(i);
            layoutInArea(child, x, y, contentWidth, actualAreaHeights[0][i],
                       /* baseline shouldn't matter */actualAreaHeights[0][i],
                       getMargin(child), isFillWidth, true,
                       hpos, vpos);
            y += actualAreaHeights[0][i] + space;
        }
    }

    private double[][] getTempArray(int size) {
        if (tempArray == null) {
            tempArray = new double[2][size]; // First array for the result, second for temporary computations
        } else if (tempArray[0].length < size) {
            tempArray = new double[2][Math.max(tempArray.length * 3, size)];
        }
        return tempArray;

    }

                                                                            *
                        Stylesheet Handling                             *
                                                                        *
/***************************************************************************
     *                                                                         *
     *                         Stylesheet Handling                             *
     *                                                                         *
     **************************************************************************/

     /*
      * Super-lazy instantiation pattern from Bill Pugh.
      */
     private static class StyleableProperties {
         private static final CssMetaData<VBox,Pos> ALIGNMENT =
             new CssMetaData<VBox,Pos>("-fx-alignment",
                 new EnumConverter<Pos>(Pos.class), Pos.TOP_LEFT){

            @Override
            public boolean isSettable(VBox node) {
                return node.alignment == null || !node.alignment.isBound();
            }

            @Override
            public StyleableProperty<Pos> getStyleableProperty(VBox node) {
                return (StyleableProperty<Pos>)node.alignmentProperty();
            }
        };

         private static final CssMetaData<VBox,Boolean> FILL_WIDTH =
             new CssMetaData<VBox,Boolean>("-fx-fill-width",
                 BooleanConverter.getInstance(), Boolean.TRUE) {

            @Override
            public boolean isSettable(VBox node) {
                return node.fillWidth == null || !node.fillWidth.isBound();
            }

            @Override
            public StyleableProperty<Boolean> getStyleableProperty(VBox node) {
                return (StyleableProperty<Boolean>)node.fillWidthProperty();
            }
        };

         private static final CssMetaData<VBox,Number> SPACING =
             new CssMetaData<VBox,Number>("-fx-spacing",
                 SizeConverter.getInstance(), 0d) {

            @Override
            public boolean isSettable(VBox node) {
                return node.spacing == null || !node.spacing.isBound();
            }

            @Override
            public StyleableProperty<Number> getStyleableProperty(VBox node) {
                return (StyleableProperty<Number>)node.spacingProperty();
            }
        };

         private static final List<CssMetaData<? extends Styleable, ?>> STYLEABLES;
         static {
            final List<CssMetaData<? extends Styleable, ?>> styleables =
                new ArrayList<CssMetaData<? extends Styleable, ?>>(Region.getClassCssMetaData());
            styleables.add(ALIGNMENT);
            styleables.add(FILL_WIDTH);
            styleables.add(SPACING);
            STYLEABLES = Collections.unmodifiableList(styleables);
         }
    }

    Returns: The CssMetaData associated with this class, which may include the
CssMetaData of its superclasses.
Since: JavaFX 8.0/**
     * @return The CssMetaData associated with this class, which may include the
     * CssMetaData of its superclasses.
     * @since JavaFX 8.0
     */
    public static List<CssMetaData<? extends Styleable, ?>> getClassCssMetaData() {
        return StyleableProperties.STYLEABLES;
    }

    {@inheritDoc}
Since: JavaFX 8.0/**
     * {@inheritDoc}
     *
     * @since JavaFX 8.0
     */


    @Override
    public List<CssMetaData<? extends Styleable, ?>> getCssMetaData() {
        return getClassCssMetaData();
    }

}
	width	height
minimum	left/right insets plus the largest of the children's min widths.	top/bottom insets plus the sum of each child's min height plus spacing between each child.
preferred	left/right insets plus the largest of the children's pref widths.	top/bottom insets plus the sum of each child's pref height plus spacing between each child.
maximum	Double.MAX_VALUE	Double.MAX_VALUE
Constraint	Type	Description
vgrow	javafx.scene.layout.Priority	The vertical grow priority for the child.
margin	javafx.geometry.Insets	Margin space around the outside of the child.
Params:	child – the child node of a vbox
Returns:	the vertical grow priority for the child or null if no priority was set
Params:	children – The initial set of children for this pane.
Since:	JavaFX 8.0
Params:	spacing – the amount of horizontal space between each child children – The initial set of children for this pane.
Since:	JavaFX 8.0
Returns:	The CssMetaData associated with this class, which may include the CssMetaData of its superclasses.
Since:	JavaFX 8.0
/

org.openjfx/ javafx-graphics/ 14/ javafx/scene/layout/VBox.java

Resizable Range

Optional Layout Constraints
