/* class BorderLayout
*
* Copyright (C) 2001 R M Pitman
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package charva.awt;
/**
* A concrete implementation of LayoutManager that lays out its components
* around its edges. The components are laid out according to their preferred
* sizes and the constraints of the container's size. The NORTH and SOUTH
* components may be stretched horizontally; the WEST and EAST components may
* be stretched vertically; the CENTER component may stretch both horiz-
* ontally and vertically to fill any space left over.
*/
public class BorderLayout implements LayoutManager2 {
public BorderLayout() {
//_hgap = 0;
//_vgap = 0;
}
public void addLayoutComponent(Component component_, Object constraint_) {
String constraint = (String) constraint_;
if (constraint.equals(NORTH))
_north = component_;
else if (constraint.equals(SOUTH))
_south = component_;
else if (constraint.equals(WEST))
_west = component_;
else if (constraint.equals(EAST))
_east = component_;
else if (constraint.equals(CENTER)) _center = component_;
}
/**
* Calculate the minimum-size rectangle that can enclose all the components
* in the given container.
*/
public Dimension minimumSize(Container container_) {
int width = 0;
int height = 0;
Dimension northSize = null;
Dimension eastSize = null;
Dimension southSize = null;
Dimension westSize = null;
Dimension centerSize = null;
/*
* Calculate the minimum height.
*/
if (_west != null) {
westSize = _west.minimumSize();
height = westSize.height;
width = westSize.width;
}
if (_center != null) {
centerSize = _center.minimumSize();
if (centerSize.height > height) height = centerSize.height;
width += centerSize.width;
}
if (_east != null) {
eastSize = _east.minimumSize();
if (eastSize.height > height) height = eastSize.height;
width += eastSize.width;
}
if (_north != null) {
northSize = _north.minimumSize();
height += northSize.height;
if (northSize.width > width) width = northSize.width;
}
if (_south != null) {
southSize = _south.minimumSize();
height += southSize.height;
if (southSize.width > width) width = southSize.width;
}
Insets insets = container_.getInsets();
height += insets.top + insets.bottom;
width += insets.left + insets.right;
return new Dimension(width, height);
}
/**
* This is called when the size of the container has already been set. It
* just lays out the components according to the specified alignment, hgap
* and vgap.
*/
public void doLayout(Container container_) {
Dimension size = container_.getSize();
Insets insets = container_.getInsets();
/*
* Expand all the containers that are in this container. In the AWT
* BorderLayout, other components such as buttons are expanded too, but
* that is not practical with text components.
*/
expandContainers(container_);
/*
* Now lay out the components inside the container.
*/
int availableHeight = size.height - insets.top - insets.bottom;
int availableWidth = size.width - insets.left - insets.bottom;
int northbottom = insets.top;
int westright = insets.left;
if (_north != null) {
int padding = size.width - _north.getSize().width;
_north.setLocation(padding / 2, insets.top);
availableHeight -= _north.getSize().height;
northbottom += _north.getSize().height;
}
if (_south != null) {
int padding = size.width - _south.getSize().width;
_south.setLocation(padding / 2, size.height - insets.bottom
- _south.getSize().height);
availableHeight -= _south.getSize().height;
}
if (_west != null) {
_west.setLocation(insets.left, northbottom
+ (availableHeight - _west.getSize().height) / 2);
availableWidth -= _west.getSize().width;
westright += _west.getSize().width;
}
if (_east != null) {
_east.setLocation(
size.width - insets.right - _east.getSize().width,
northbottom + (availableHeight - _east.getSize().height)
/ 2);
availableWidth -= _east.getSize().width;
}
if (_center != null) {
_center.setLocation(westright
+ (availableWidth - _center.getSize().width) / 2,
northbottom + (availableHeight - _center.getSize().height)
/ 2);
}
}
/**
* Invalidates the layout, indicating that if the layout manager has cached
* information it should be discarded.
*/
public void invalidateLayout(Container target_) {
}
/**
* Expand all the containers that are inside the specified container.
*/
private void expandContainers(Container container_) {
Dimension size = container_.getSize();
Insets insets = container_.getInsets();
int availableHeight = size.height - insets.top - insets.bottom;
int availableWidth = size.width - insets.left - insets.right;
if (_north != null) {
if (_north instanceof Container) {
((Container) _north).setWidth(availableWidth);
((Container) _north).setHeight(_north.minimumSize().height);
((Container) _north).doLayout();
}
availableHeight -= _north.getSize().height;
}
if (_south != null) {
if (_south instanceof Container) {
((Container) _south).setWidth(availableWidth);
((Container) _south).setHeight(_south.minimumSize().height);
((Container) _south).doLayout();
}
availableHeight -= _south.getSize().height;
}
if (_west != null) {
if (_west instanceof Container) {
((Container) _west).setWidth(_west.minimumSize().width);
((Container) _west).setHeight(availableHeight);
((Container) _west).doLayout();
}
availableWidth -= _west.getSize().width;
}
if (_east != null) {
if (_east instanceof Container) {
((Container) _east).setWidth(_east.minimumSize().width);
((Container) _east).setHeight(availableHeight);
((Container) _east).doLayout();
}
availableWidth -= _east.getSize().width;
}
if (_center != null && _center instanceof Container) {
((Container) _center).setSize(availableWidth, availableHeight);
((Container) _center).doLayout();
}
}
//====================================================================
// INSTANCE VARIABLES
//private final int _hgap = 0;
//private final int _vgap = 0;
private Component _north = null;
private Component _south = null;
private Component _west = null;
private Component _east = null;
private Component _center = null;
public static final String NORTH = "North";
public static final String SOUTH = "South";
public static final String EAST = "East";
public static final String WEST = "West";
public static final String CENTER = "Center";
}