/*
* @(#)FlowLayout.java 1.17 95/11/14 Arthur van Hoff
*
* Copyright (c) 1994 Sun Microsystems, Inc. All Rights Reserved.
*
* Permission to use, copy, modify, and distribute this software
* and its documentation for NON-COMMERCIAL purposes and without
* fee is hereby granted provided that this copyright notice
* appears in all copies. Please refer to the file "copyright.html"
* for further important copyright and licensing information.
*
* SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
* THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
* TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
* ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
*/
package java.awt;
/**
* Flow layout is used to layout buttons in a panel. It will arrange
* buttons left to right until no more buttons fit on the same line.
* Each line is centered.
*
* @version 1.17, 14 Nov 1995
* @author Arthur van Hoff
* @author Sami Shaio
*/
public class FlowLayout implements LayoutManager {
/**
* The left alignment variable.
*/
public static final int LEFT = 0;
/**
* The right alignment variable.
*/
public static final int CENTER = 1;
/**
* The right alignment variable.
*/
public static final int RIGHT = 2;
int align;
int hgap;
int vgap;
/**
* Constructs a new Flow Layout with a centered alignment.
*/
public FlowLayout() {
this(CENTER, 5, 5);
}
/**
* Constructs a new Flow Layout with the specified alignment.
* @param align the alignment value
*/
public FlowLayout(int align) {
this(align, 5, 5);
}
/**
* Constructs a new Flow Layout with the specified alignment and gap
* values.
* @param align the alignment value
* @param hgap the horizontal gap variable
* @param vgap the vertical gap variable
*/
public FlowLayout(int align, int hgap, int vgap) {
this.align = align;
this.hgap = hgap;
this.vgap = vgap;
}
/**
* Adds the specified component to the layout. Does not apply.
* @param name the name of the component
* @param comp the the component to be added
*/
public void addLayoutComponent(String name, Component comp) {
}
/**
* Removes the specified component from the layout. Does not apply.
* @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
* @see Container
* @see #minimumLayoutSize
*/
public Dimension preferredLayoutSize(Container target) {
Dimension dim = new Dimension(0, 0);
int nmembers = target.countComponents();
for (int i = 0 ; i < nmembers ; i++) {
Component m = target.getComponent(i);
if (m.visible) {
Dimension d = m.preferredSize();
dim.height = Math.max(dim.height, d.height);
if (i > 0) {
dim.width += hgap;
}
dim.width += d.width;
}
}
Insets insets = target.insets();
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
* @see #preferredLayoutSize
*/
public Dimension minimumLayoutSize(Container target) {
Dimension dim = new Dimension(0, 0);
int nmembers = target.countComponents();
for (int i = 0 ; i < nmembers ; i++) {
Component m = target.getComponent(i);
if (m.visible) {
Dimension d = m.minimumSize();
dim.height = Math.max(dim.height, d.height);
if (i > 0) {
dim.width += hgap;
}
dim.width += d.width;
}
}
Insets insets = target.insets();
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) {
switch (align) {
case LEFT:
break;
case CENTER:
x += width / 2;
break;
case RIGHT:
x += width;
break;
}
for (int i = rowStart ; i < rowEnd ; i++) {
Component m = target.getComponent(i);
if (m.visible) {
m.move(x, y + (height - m.height) / 2);
x += hgap + m.width;
}
}
}
/**
* Lays out the container. This method will actually reshape the
* components in target in order to satisfy the constraints of
* the BorderLayout object.
* @param target the specified component being laid out.
* @see Container
*/
public void layoutContainer(Container target) {
Insets insets = target.insets();
int maxwidth = target.width - (insets.left + insets.right + hgap*2);
int nmembers = target.countComponents();
int x = 0, y = insets.top + vgap;
int rowh = 0, start = 0;
for (int i = 0 ; i < nmembers ; i++) {
Component m = target.getComponent(i);
if (m.visible) {
Dimension d = m.preferredSize();
m.resize(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 + hgap, y, maxwidth - x, rowh, start, i);
x = d.width;
y += vgap + rowh;
rowh = d.height;
start = i;
}
}
}
moveComponents(target, insets.left + hgap, y, maxwidth - x, rowh, start, nmembers);
}
/**
* Returns the String representation of this FlowLayout's values.
*/
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;
}
return getClass().getName() + "[hgap=" + hgap + ",vgap=" + vgap + str + "]";
}
}