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/*
 * IzPack - Copyright 2001-2008 Julien Ponge, All Rights Reserved.
 * 
 * http://izpack.org/
 * http://izpack.codehaus.org/
 * 
 * Copyright 2002 Elmar Grom
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 *     
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.izforge.izpack.gui;

import java.awt.*;

/*---------------------------------------------------------------------------*/
/**
 * A flow layout arranges components in a left-to-right flow, much like lines of text in a
 * paragraph. Flow layouts are typically used to arrange buttons in a panel. It will arrange buttons
 * left to right until no more buttons fit on the same line. Each line is centered.
 * 

* For example, the following picture shows an applet using the flow layout manager (its default * layout manager) to position three buttons: *

* Graphic of Layout for Three Buttons *

* Here is the code for this applet: *

*


*
*

*

 * 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); * } * } *

*

*

*

*
*

* A flow layout lets each component assume its natural (preferred) size. *

* This class is a bit different from java.awt.FlowLayout.

java.awt.FlowLayout has a * minor problem that was bugging me when I wrote the UserInputPanel. FlowLayout puts some amount of * space in between each component that it lays out. In addition it adds that same amount of space * to the left and to the right of the entire group. Therefore items such as the RuleInputfield that * are laid out with a FlowLayout would never line up properly with the other components (it would * appear to be slightly indented). Because there is no way to circumvent this behavior in * FlowLayout (it's hard coded) I copied the source and modified it so that it does not add the * space to the left and to the right. Now my stuff lines up properly. (Elmar Grom)
* * @author Arthur van Hoff * @author Sami Shaio * @author Elmar Grom * @version 1.39, 11/29/02 */ /*---------------------------------------------------------------------------*/ public class FlowLayout implements LayoutManager { /** * 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 Package-private pending API change approval */ public static final int LEADING = 3; /** * This value indicates that each row of components should be justified to the leading 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 Package-private pending API change approval */ public static final int TRAILING = 4; /** * align is the proprty that determines how each row distributes empty space. It * can be one of the following three values : LEFT * RIGHT * CENTER * * @serial * @see #getAlignment * @see #setAlignment */ int align; // This is for 1.1 serialization compatibilitys /** * 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 : * LEFT * RIGHT * CENTER * * @serial * @see #getAlignment * @see #setAlignment * @since 1.2 */ int newAlign; // This is the one we actually use /** * The flow layout manager allows a seperation of components with gaps. The horizontal gap will * specify the space between components. * * @serial * @see #getHgap * @see #setHgap */ int hgap; /** * The flow layout manager allows a seperation of components with gaps. The vertical gap will * specify the space between rows. * * @serial * @see #getVgap * @see #setVgap */ int vgap; /*--------------------------------------------------------------------------*/ /** * Constructs a new Flow Layout with a centered alignment and a default 5-unit horizontal and * vertical gap. */ /*--------------------------------------------------------------------------*/ public FlowLayout() { this(CENTER, 5, 5); } /*--------------------------------------------------------------------------*/ /** * Constructs a new Flow Layout with the specified alignment and a default 5-unit horizontal and * vertical gap. The value of the alignment argument must be one of FlowLayout.LEFT, * FlowLayout.RIGHT, or FlowLayout.CENTER. * * @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. *

* The value of the alignment argument must be one of FlowLayout.LEFT, * FlowLayout.RIGHT, or FlowLayout.CENTER. * * @param align the alignment value. * @param hgap the horizontal gap between components. * @param vgap the vertical gap between components. */ /*--------------------------------------------------------------------------*/ 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 FlowLayout.LEFT, * FlowLayout.RIGHT, or FlowLayout.CENTER. * * @return the alignment value for this layout. * @see java.awt.FlowLayout#setAlignment */ /*--------------------------------------------------------------------------*/ public int getAlignment() { return (newAlign); } /*--------------------------------------------------------------------------*/ /** * Sets the alignment for this layout. Possible values are FlowLayout.LEFT, * FlowLayout.RIGHT, and FlowLayout.CENTER. * * @param align the alignment value. * @see #getAlignment() */ /*--------------------------------------------------------------------------*/ 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. * * @return the horizontal gap between components. * @see #setHgap(int) */ /*--------------------------------------------------------------------------*/ public int getHgap() { return (hgap); } /*--------------------------------------------------------------------------*/ /** * Sets the horizontal gap between components. * * @param hgap the horizontal gap between components * @see #getHgap() */ /*--------------------------------------------------------------------------*/ public void setHgap(int hgap) { this.hgap = hgap; } /*--------------------------------------------------------------------------*/ /** * Gets the vertical gap between components. * * @return the vertical gap between components.\ * @see #setVgap(int) */ /*--------------------------------------------------------------------------*/ public int getVgap() { return (vgap); } /*--------------------------------------------------------------------------*/ /** * Sets the vertical gap between components. * * @param vgap the vertical gap between components * @see #getVgap() */ /*--------------------------------------------------------------------------*/ public void setVgap(int vgap) { this.vgap = vgap; } /*--------------------------------------------------------------------------*/ /** * 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 */ /*--------------------------------------------------------------------------*/ public void removeLayoutComponent(Component comp) { } /*--------------------------------------------------------------------------*/ /** * Returns the preferred dimensions for this layout given the components in the specified target * container. * * @param target the component which needs to be laid out * @return the preferred dimensions to lay out the subcomponents of the specified container. * @see #minimumLayoutSize(Container) */ /*--------------------------------------------------------------------------*/ public Dimension preferredLayoutSize(Container target) { synchronized (target.getTreeLock()) { Dimension dim = new Dimension(0, 0); int nmembers = target.getComponentCount(); boolean firstVisibleComponent = true; 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; } } 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 components contained in the specified * target container. * * @param target the component which needs to be laid out * @return the minimum dimensions to lay out the subcomponents of the specified container. * @see #preferredLayoutSize(Container) */ /*--------------------------------------------------------------------------*/ public Dimension minimumLayoutSize(Container target) { synchronized (target.getTreeLock()) { Dimension dim = new Dimension(0, 0); int nmembers = target.getComponentCount(); for (int i = 0; i < nmembers; i++) { Component m = target.getComponent(i); if (m.isVisible()) { Dimension d = m.getMinimumSize(); dim.height = Math.max(dim.height, d.height); if (i > 0) { dim.width += hgap; } dim.width += d.width; } } 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 the ending of the row */ /*--------------------------------------------------------------------------*/ private void moveComponents(Container target, int x, int y, int width, int height, int rowStart, int rowEnd, boolean ltr) { synchronized (target.getTreeLock()) { 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; } for (int i = rowStart; i < rowEnd; i++) { Component m = target.getComponent(i); if (m.isVisible()) { if (ltr) { m.setLocation(x, y + (height - m.getSize().height) / 2); } else { m.setLocation(target.getSize().width - x - m.getSize().width, y + (height - m.getSize().height) / 2); } x += m.getSize().width + hgap; } } } } /*--------------------------------------------------------------------------*/ /** * Lays out the container. This method lets each component take its preferred size by reshaping * the components in the target container in order to satisfy the constraints of this * FlowLayout object. * * @param target the specified component being laid out. */ /*--------------------------------------------------------------------------*/ public void layoutContainer(Container target) { synchronized (target.getTreeLock()) { Insets insets = target.getInsets(); int maxWidth = target.getSize().width - (insets.left + insets.right + hgap * 2); int nMembers = target.getComponentCount(); int x = 0; int y = insets.top + vgap; int rowh = 0; int start = 0; boolean ltr = target.getComponentOrientation().isLeftToRight(); 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 ((x == 0) || ((x + d.width) <= maxWidth)) { if (x > 0) { x += hgap; } x += d.width; rowh = Math.max(rowh, d.height); } else { moveComponents(target, insets.left, y, maxWidth - x, rowh, start, i, ltr); x = d.width; y += vgap + rowh; rowh = d.height; start = i; } } } moveComponents(target, insets.left, y, maxWidth - x, rowh, start, nMembers, ltr); } } /*--------------------------------------------------------------------------*/ /** * Returns a string representation of this 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 + "]"); } } /*---------------------------------------------------------------------------*/





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