| /* |
| * Copyright (c) 1995, 2013, 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 java.awt; |
| |
| import java.io.ObjectInputStream; |
| import java.io.IOException; |
| |
| /** |
| * A flow layout arranges components in a directional flow, much |
| * like lines of text in a paragraph. The flow direction is |
| * determined by the container's {@code componentOrientation} |
| * property and may be one of two values: |
| * <ul> |
| * <li>{@code ComponentOrientation.LEFT_TO_RIGHT} |
| * <li>{@code ComponentOrientation.RIGHT_TO_LEFT} |
| * </ul> |
| * Flow layouts are typically used |
| * to arrange buttons in a panel. It arranges buttons |
| * horizontally until no more buttons fit on the same line. |
| * The line alignment is determined by the {@code align} |
| * property. The possible values are: |
| * <ul> |
| * <li>{@link #LEFT LEFT} |
| * <li>{@link #RIGHT RIGHT} |
| * <li>{@link #CENTER CENTER} |
| * <li>{@link #LEADING LEADING} |
| * <li>{@link #TRAILING TRAILING} |
| * </ul> |
| * <p> |
| * For example, the following picture shows an applet using the flow |
| * layout manager (its default layout manager) to position three buttons: |
| * <p> |
| * <img src="doc-files/FlowLayout-1.gif" |
| * ALT="Graphic of Layout for Three Buttons" |
| * style="float:center; margin: 7px 10px;"> |
| * <p> |
| * Here is the code for this applet: |
| * |
| * <hr><blockquote><pre> |
| * import java.awt.*; |
| * import java.applet.Applet; |
| * |
| * public class myButtons extends Applet { |
| * Button button1, button2, button3; |
| * public void init() { |
| * button1 = new Button("Ok"); |
| * button2 = new Button("Open"); |
| * button3 = new Button("Close"); |
| * add(button1); |
| * add(button2); |
| * add(button3); |
| * } |
| * } |
| * </pre></blockquote><hr> |
| * <p> |
| * A flow layout lets each component assume its natural (preferred) size. |
| * |
| * @author Arthur van Hoff |
| * @author Sami Shaio |
| * @since 1.0 |
| * @see ComponentOrientation |
| */ |
| public class FlowLayout implements LayoutManager, java.io.Serializable { |
| |
| /** |
| * This value indicates that each row of components |
| * should be left-justified. |
| */ |
| public static final int LEFT = 0; |
| |
| /** |
| * This value indicates that each row of components |
| * should be centered. |
| */ |
| public static final int CENTER = 1; |
| |
| /** |
| * This value indicates that each row of components |
| * should be right-justified. |
| */ |
| public static final int RIGHT = 2; |
| |
| /** |
| * This value indicates that each row of components |
| * should be justified to the leading edge of the container's |
| * orientation, for example, to the left in left-to-right orientations. |
| * |
| * @see java.awt.Component#getComponentOrientation |
| * @see java.awt.ComponentOrientation |
| * @since 1.2 |
| */ |
| public static final int LEADING = 3; |
| |
| /** |
| * This value indicates that each row of components |
| * should be justified to the trailing edge of the container's |
| * orientation, for example, to the right in left-to-right orientations. |
| * |
| * @see java.awt.Component#getComponentOrientation |
| * @see java.awt.ComponentOrientation |
| * @since 1.2 |
| */ |
| public static final int TRAILING = 4; |
| |
| /** |
| * {@code align} is the property that determines |
| * how each row distributes empty space. |
| * It can be one of the following values: |
| * <ul> |
| * <li>{@code LEFT} |
| * <li>{@code RIGHT} |
| * <li>{@code CENTER} |
| * </ul> |
| * |
| * @serial |
| * @see #getAlignment |
| * @see #setAlignment |
| */ |
| int align; // This is for 1.1 serialization compatibility |
| |
| /** |
| * {@code newAlign} is the property that determines |
| * how each row distributes empty space for the Java 2 platform, |
| * v1.2 and greater. |
| * It can be one of the following three values: |
| * <ul> |
| * <li>{@code LEFT} |
| * <li>{@code RIGHT} |
| * <li>{@code CENTER} |
| * <li>{@code LEADING} |
| * <li>{@code TRAILING} |
| * </ul> |
| * |
| * @serial |
| * @since 1.2 |
| * @see #getAlignment |
| * @see #setAlignment |
| */ |
| int newAlign; // This is the one we actually use |
| |
| /** |
| * The flow layout manager allows a separation of |
| * components with gaps. The horizontal gap will |
| * specify the space between components and between |
| * the components and the borders of the |
| * {@code Container}. |
| * |
| * @serial |
| * @see #getHgap() |
| * @see #setHgap(int) |
| */ |
| int hgap; |
| |
| /** |
| * The flow layout manager allows a separation of |
| * components with gaps. The vertical gap will |
| * specify the space between rows and between the |
| * the rows and the borders of the {@code Container}. |
| * |
| * @serial |
| * @see #getHgap() |
| * @see #setHgap(int) |
| */ |
| int vgap; |
| |
| /** |
| * If true, components will be aligned on their baseline. |
| */ |
| private boolean alignOnBaseline; |
| |
| /* |
| * JDK 1.1 serialVersionUID |
| */ |
| private static final long serialVersionUID = -7262534875583282631L; |
| |
| /** |
| * Constructs a new {@code FlowLayout} with a centered alignment and a |
| * default 5-unit horizontal and vertical gap. |
| */ |
| public FlowLayout() { |
| this(CENTER, 5, 5); |
| } |
| |
| /** |
| * Constructs a new {@code FlowLayout} with the specified |
| * alignment and a default 5-unit horizontal and vertical gap. |
| * The value of the alignment argument must be one of |
| * {@code FlowLayout.LEFT}, {@code FlowLayout.RIGHT}, |
| * {@code FlowLayout.CENTER}, {@code FlowLayout.LEADING}, |
| * or {@code FlowLayout.TRAILING}. |
| * @param align the alignment value |
| */ |
| public FlowLayout(int align) { |
| this(align, 5, 5); |
| } |
| |
| /** |
| * Creates a new flow layout manager with the indicated alignment |
| * and the indicated horizontal and vertical gaps. |
| * <p> |
| * The value of the alignment argument must be one of |
| * {@code FlowLayout.LEFT}, {@code FlowLayout.RIGHT}, |
| * {@code FlowLayout.CENTER}, {@code FlowLayout.LEADING}, |
| * or {@code FlowLayout.TRAILING}. |
| * @param align the alignment value |
| * @param hgap the horizontal gap between components |
| * and between the components and the |
| * borders of the {@code Container} |
| * @param vgap the vertical gap between components |
| * and between the components and the |
| * borders of the {@code Container} |
| */ |
| public FlowLayout(int align, int hgap, int vgap) { |
| this.hgap = hgap; |
| this.vgap = vgap; |
| setAlignment(align); |
| } |
| |
| /** |
| * Gets the alignment for this layout. |
| * Possible values are {@code FlowLayout.LEFT}, |
| * {@code FlowLayout.RIGHT}, {@code FlowLayout.CENTER}, |
| * {@code FlowLayout.LEADING}, |
| * or {@code FlowLayout.TRAILING}. |
| * @return the alignment value for this layout |
| * @see java.awt.FlowLayout#setAlignment |
| * @since 1.1 |
| */ |
| public int getAlignment() { |
| return newAlign; |
| } |
| |
| /** |
| * Sets the alignment for this layout. |
| * Possible values are |
| * <ul> |
| * <li>{@code FlowLayout.LEFT} |
| * <li>{@code FlowLayout.RIGHT} |
| * <li>{@code FlowLayout.CENTER} |
| * <li>{@code FlowLayout.LEADING} |
| * <li>{@code FlowLayout.TRAILING} |
| * </ul> |
| * @param align one of the alignment values shown above |
| * @see #getAlignment() |
| * @since 1.1 |
| */ |
| public void setAlignment(int align) { |
| this.newAlign = align; |
| |
| // this.align is used only for serialization compatibility, |
| // so set it to a value compatible with the 1.1 version |
| // of the class |
| |
| switch (align) { |
| case LEADING: |
| this.align = LEFT; |
| break; |
| case TRAILING: |
| this.align = RIGHT; |
| break; |
| default: |
| this.align = align; |
| break; |
| } |
| } |
| |
| /** |
| * Gets the horizontal gap between components |
| * and between the components and the borders |
| * of the {@code Container} |
| * |
| * @return the horizontal gap between components |
| * and between the components and the borders |
| * of the {@code Container} |
| * @see java.awt.FlowLayout#setHgap |
| * @since 1.1 |
| */ |
| public int getHgap() { |
| return hgap; |
| } |
| |
| /** |
| * Sets the horizontal gap between components and |
| * between the components and the borders of the |
| * {@code Container}. |
| * |
| * @param hgap the horizontal gap between components |
| * and between the components and the borders |
| * of the {@code Container} |
| * @see java.awt.FlowLayout#getHgap |
| * @since 1.1 |
| */ |
| public void setHgap(int hgap) { |
| this.hgap = hgap; |
| } |
| |
| /** |
| * Gets the vertical gap between components and |
| * between the components and the borders of the |
| * {@code Container}. |
| * |
| * @return the vertical gap between components |
| * and between the components and the borders |
| * of the {@code Container} |
| * @see java.awt.FlowLayout#setVgap |
| * @since 1.1 |
| */ |
| public int getVgap() { |
| return vgap; |
| } |
| |
| /** |
| * Sets the vertical gap between components and between |
| * the components and the borders of the {@code Container}. |
| * |
| * @param vgap the vertical gap between components |
| * and between the components and the borders |
| * of the {@code Container} |
| * @see java.awt.FlowLayout#getVgap |
| * @since 1.1 |
| */ |
| public void setVgap(int vgap) { |
| this.vgap = vgap; |
| } |
| |
| /** |
| * Sets whether or not components should be vertically aligned along their |
| * baseline. Components that do not have a baseline will be centered. |
| * The default is false. |
| * |
| * @param alignOnBaseline whether or not components should be |
| * vertically aligned on their baseline |
| * @since 1.6 |
| */ |
| public void setAlignOnBaseline(boolean alignOnBaseline) { |
| this.alignOnBaseline = alignOnBaseline; |
| } |
| |
| /** |
| * Returns true if components are to be vertically aligned along |
| * their baseline. The default is false. |
| * |
| * @return true if components are to be vertically aligned along |
| * their baseline |
| * @since 1.6 |
| */ |
| public boolean getAlignOnBaseline() { |
| return alignOnBaseline; |
| } |
| |
| /** |
| * Adds the specified component to the layout. |
| * Not used by this class. |
| * @param name the name of the component |
| * @param comp the component to be added |
| */ |
| public void addLayoutComponent(String name, Component comp) { |
| } |
| |
| /** |
| * Removes the specified component from the layout. |
| * Not used by this class. |
| * @param comp the component to remove |
| * @see java.awt.Container#removeAll |
| */ |
| public void removeLayoutComponent(Component comp) { |
| } |
| |
| /** |
| * Returns the preferred dimensions for this layout given the |
| * <i>visible</i> components in the specified target container. |
| * |
| * @param target the container that needs to be laid out |
| * @return the preferred dimensions to lay out the |
| * subcomponents of the specified container |
| * @see Container |
| * @see #minimumLayoutSize |
| * @see java.awt.Container#getPreferredSize |
| */ |
| public Dimension preferredLayoutSize(Container target) { |
| synchronized (target.getTreeLock()) { |
| Dimension dim = new Dimension(0, 0); |
| int nmembers = target.getComponentCount(); |
| boolean firstVisibleComponent = true; |
| boolean useBaseline = getAlignOnBaseline(); |
| int maxAscent = 0; |
| int maxDescent = 0; |
| |
| for (int i = 0 ; i < nmembers ; i++) { |
| Component m = target.getComponent(i); |
| if (m.isVisible()) { |
| Dimension d = m.getPreferredSize(); |
| dim.height = Math.max(dim.height, d.height); |
| if (firstVisibleComponent) { |
| firstVisibleComponent = false; |
| } else { |
| dim.width += hgap; |
| } |
| dim.width += d.width; |
| if (useBaseline) { |
| int baseline = m.getBaseline(d.width, d.height); |
| if (baseline >= 0) { |
| maxAscent = Math.max(maxAscent, baseline); |
| maxDescent = Math.max(maxDescent, d.height - baseline); |
| } |
| } |
| } |
| } |
| if (useBaseline) { |
| dim.height = Math.max(maxAscent + maxDescent, dim.height); |
| } |
| Insets insets = target.getInsets(); |
| dim.width += insets.left + insets.right + hgap*2; |
| dim.height += insets.top + insets.bottom + vgap*2; |
| return dim; |
| } |
| } |
| |
| /** |
| * Returns the minimum dimensions needed to layout the <i>visible</i> |
| * components contained in the specified target container. |
| * @param target the container that needs to be laid out |
| * @return the minimum dimensions to lay out the |
| * subcomponents of the specified container |
| * @see #preferredLayoutSize |
| * @see java.awt.Container |
| * @see java.awt.Container#doLayout |
| */ |
| public Dimension minimumLayoutSize(Container target) { |
| synchronized (target.getTreeLock()) { |
| boolean useBaseline = getAlignOnBaseline(); |
| Dimension dim = new Dimension(0, 0); |
| int nmembers = target.getComponentCount(); |
| int maxAscent = 0; |
| int maxDescent = 0; |
| boolean firstVisibleComponent = true; |
| |
| for (int i = 0 ; i < nmembers ; i++) { |
| Component m = target.getComponent(i); |
| if (m.visible) { |
| Dimension d = m.getMinimumSize(); |
| dim.height = Math.max(dim.height, d.height); |
| if (firstVisibleComponent) { |
| firstVisibleComponent = false; |
| } else { |
| dim.width += hgap; |
| } |
| dim.width += d.width; |
| if (useBaseline) { |
| int baseline = m.getBaseline(d.width, d.height); |
| if (baseline >= 0) { |
| maxAscent = Math.max(maxAscent, baseline); |
| maxDescent = Math.max(maxDescent, |
| dim.height - baseline); |
| } |
| } |
| } |
| } |
| |
| if (useBaseline) { |
| dim.height = Math.max(maxAscent + maxDescent, dim.height); |
| } |
| |
| Insets insets = target.getInsets(); |
| dim.width += insets.left + insets.right + hgap*2; |
| dim.height += insets.top + insets.bottom + vgap*2; |
| return dim; |
| |
| |
| |
| |
| |
| } |
| } |
| |
| /** |
| * Centers the elements in the specified row, if there is any slack. |
| * @param target the component which needs to be moved |
| * @param x the x coordinate |
| * @param y the y coordinate |
| * @param width the width dimensions |
| * @param height the height dimensions |
| * @param rowStart the beginning of the row |
| * @param rowEnd the ending of the row |
| * @param useBaseline Whether or not to align on baseline. |
| * @param ascent Ascent for the components. This is only valid if |
| * useBaseline is true. |
| * @param descent Ascent for the components. This is only valid if |
| * useBaseline is true. |
| * @return actual row height |
| */ |
| private int moveComponents(Container target, int x, int y, int width, int height, |
| int rowStart, int rowEnd, boolean ltr, |
| boolean useBaseline, int[] ascent, |
| int[] descent) { |
| switch (newAlign) { |
| case LEFT: |
| x += ltr ? 0 : width; |
| break; |
| case CENTER: |
| x += width / 2; |
| break; |
| case RIGHT: |
| x += ltr ? width : 0; |
| break; |
| case LEADING: |
| break; |
| case TRAILING: |
| x += width; |
| break; |
| } |
| int maxAscent = 0; |
| int nonbaselineHeight = 0; |
| int baselineOffset = 0; |
| if (useBaseline) { |
| int maxDescent = 0; |
| for (int i = rowStart ; i < rowEnd ; i++) { |
| Component m = target.getComponent(i); |
| if (m.visible) { |
| if (ascent[i] >= 0) { |
| maxAscent = Math.max(maxAscent, ascent[i]); |
| maxDescent = Math.max(maxDescent, descent[i]); |
| } |
| else { |
| nonbaselineHeight = Math.max(m.getHeight(), |
| nonbaselineHeight); |
| } |
| } |
| } |
| height = Math.max(maxAscent + maxDescent, nonbaselineHeight); |
| baselineOffset = (height - maxAscent - maxDescent) / 2; |
| } |
| for (int i = rowStart ; i < rowEnd ; i++) { |
| Component m = target.getComponent(i); |
| if (m.isVisible()) { |
| int cy; |
| if (useBaseline && ascent[i] >= 0) { |
| cy = y + baselineOffset + maxAscent - ascent[i]; |
| } |
| else { |
| cy = y + (height - m.height) / 2; |
| } |
| if (ltr) { |
| m.setLocation(x, cy); |
| } else { |
| m.setLocation(target.width - x - m.width, cy); |
| } |
| x += m.width + hgap; |
| } |
| } |
| return height; |
| } |
| |
| /** |
| * Lays out the container. This method lets each |
| * <i>visible</i> component take |
| * its preferred size by reshaping the components in the |
| * target container in order to satisfy the alignment of |
| * this {@code FlowLayout} object. |
| * |
| * @param target the specified component being laid out |
| * @see Container |
| * @see java.awt.Container#doLayout |
| */ |
| public void layoutContainer(Container target) { |
| synchronized (target.getTreeLock()) { |
| Insets insets = target.getInsets(); |
| int maxwidth = target.width - (insets.left + insets.right + hgap*2); |
| int nmembers = target.getComponentCount(); |
| int x = 0, y = insets.top + vgap; |
| int rowh = 0, start = 0; |
| |
| boolean ltr = target.getComponentOrientation().isLeftToRight(); |
| |
| boolean useBaseline = getAlignOnBaseline(); |
| int[] ascent = null; |
| int[] descent = null; |
| |
| if (useBaseline) { |
| ascent = new int[nmembers]; |
| descent = new int[nmembers]; |
| } |
| |
| for (int i = 0 ; i < nmembers ; i++) { |
| Component m = target.getComponent(i); |
| if (m.isVisible()) { |
| Dimension d = m.getPreferredSize(); |
| m.setSize(d.width, d.height); |
| |
| if (useBaseline) { |
| int baseline = m.getBaseline(d.width, d.height); |
| if (baseline >= 0) { |
| ascent[i] = baseline; |
| descent[i] = d.height - baseline; |
| } |
| else { |
| ascent[i] = -1; |
| } |
| } |
| if ((x == 0) || ((x + d.width) <= maxwidth)) { |
| if (x > 0) { |
| x += hgap; |
| } |
| x += d.width; |
| rowh = Math.max(rowh, d.height); |
| } else { |
| rowh = moveComponents(target, insets.left + hgap, y, |
| maxwidth - x, rowh, start, i, ltr, |
| useBaseline, ascent, descent); |
| x = d.width; |
| y += vgap + rowh; |
| rowh = d.height; |
| start = i; |
| } |
| } |
| } |
| moveComponents(target, insets.left + hgap, y, maxwidth - x, rowh, |
| start, nmembers, ltr, useBaseline, ascent, descent); |
| } |
| } |
| |
| // |
| // the internal serial version which says which version was written |
| // - 0 (default) for versions before the Java 2 platform, v1.2 |
| // - 1 for version >= Java 2 platform v1.2, which includes "newAlign" field |
| // |
| private static final int currentSerialVersion = 1; |
| /** |
| * This represent the {@code currentSerialVersion} |
| * which is bein used. It will be one of two values: |
| * {@code 0} versions before Java 2 platform v1.2, |
| * {@code 1} versions after Java 2 platform v1.2. |
| * |
| * @serial |
| * @since 1.2 |
| */ |
| private int serialVersionOnStream = currentSerialVersion; |
| |
| /** |
| * Reads this object out of a serialization stream, handling |
| * objects written by older versions of the class that didn't contain all |
| * of the fields we use now.. |
| */ |
| private void readObject(ObjectInputStream stream) |
| throws IOException, ClassNotFoundException |
| { |
| stream.defaultReadObject(); |
| |
| if (serialVersionOnStream < 1) { |
| // "newAlign" field wasn't present, so use the old "align" field. |
| setAlignment(this.align); |
| } |
| serialVersionOnStream = currentSerialVersion; |
| } |
| |
| /** |
| * Returns a string representation of this {@code FlowLayout} |
| * object and its values. |
| * @return a string representation of this layout |
| */ |
| public String toString() { |
| String str = ""; |
| switch (align) { |
| case LEFT: str = ",align=left"; break; |
| case CENTER: str = ",align=center"; break; |
| case RIGHT: str = ",align=right"; break; |
| case LEADING: str = ",align=leading"; break; |
| case TRAILING: str = ",align=trailing"; break; |
| } |
| return getClass().getName() + "[hgap=" + hgap + ",vgap=" + vgap + str + "]"; |
| } |
| |
| |
| } |
