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Diffstat (limited to 'javax/swing/SpringLayout.java')
| -rw-r--r-- | javax/swing/SpringLayout.java | 660 |
1 files changed, 660 insertions, 0 deletions
diff --git a/javax/swing/SpringLayout.java b/javax/swing/SpringLayout.java new file mode 100644 index 000000000..60a50525f --- /dev/null +++ b/javax/swing/SpringLayout.java @@ -0,0 +1,660 @@ +/* SpringLayout.java -- + Copyright (C) 2004 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA +02111-1307 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package javax.swing; + +import java.awt.Component; +import java.awt.Container; +import java.awt.Dimension; +import java.awt.LayoutManager2; + +import java.util.HashMap; +import java.util.Map; + +import javax.swing.Spring; + +/** + * A very flexible layout manager. Components are laid out by defining the + * relationships between them. The relationships are expressed as + * {@link Spring}s. You can attach a Spring for each edge of a component and + * link it to an edge of a different component. For example, you can say, + * the northern edge of component A should be attached to the southern edge + * of component B, and the space between them should be something between + * x and y pixels, and preferably z pixels. + * <p>While quite simple, this layout manager can be used to emulate most other + * layout managers, and can also be used to solve some layout problems, which + * would be hard to solve with other layout managers.</p> + * + * @author Roman Kennke (roman@ontographics.com) + */ +public class SpringLayout implements LayoutManager2 +{ + + /** The right edge of a component. */ + public static final String EAST = "East"; + + /** The top edge of a component. */ + public static final String NORTH = "North"; + + /** The bottom edge of a component. */ + public static final String SOUTH = "South"; + + /** The left edge of a component. */ + public static final String WEST = "West"; + + /** maps components to their constraints. */ + private Map constraintsMap; + + /** + * The constraints that define the relationships between components. + * Each Constraints object can hold 4 Springs: one for each edge of the + * component. Additionally it can hold Springs for the components width + * and the components height. Since the height and width constraints are + * dependend on the other constraints, a component can be over-constraint. + * In this case (like when all of NORTH, SOUTH and HEIGHT are constraint), + * the values are adjusted, so that the mathematics still hold true. + * + * @author Roman Kennke (roman@ontographics.com) + */ + public final static class Constraints + { + + // The constraints for each edge, and width and height. + /** The Spring for the left edge. */ + private Spring x; + + /** The Spring for the upper edge. */ + private Spring y; + + /** The Spring for the height. */ + private Spring height; + + /** The Spring for the width. */ + private Spring width; + + /** The Spring for the right edge. */ + private Spring east; + + /** The Spring for the bottom edge. */ + private Spring south; + + /** + * Creates a new Constraints object. + * There is no constraint set. + */ + public Constraints() + { + x = y = height = width = east = south = null; + } + + /** + * Creates a new Constraints object. + * + * @param x the constraint for the left edge of the component. + * @param y the constraint for the upper edge of the component. + */ + public Constraints(Spring x, Spring y) + { + this.x = x; + this.y = y; + width = height = east = south = null; + } + + /** + * Creates a new Constraints object. + * + * @param x the constraint for the left edge of the component. + * @param y the constraint for the upper edge of the component. + * @param width the constraint for the width of the component. + * @param height the constraint for the height of the component. + */ + public Constraints(Spring x, Spring y, Spring width, Spring height) + { + this.x = x; + this.y = y; + this.width = width; + this.height = height; + east = south = null; + } + + /** + * Returns the constraint for the edge with the <code>edgeName</code>. + * This is expected to be one of + * {@link #EAST}, {@link #WEST}, {@link NORTH} or {@link SOUTH}. + * + * @param edgeName the name of the edge. + * @return the constraint for the specified edge. + */ + public Spring getConstraint(String edgeName) + { + Spring retVal = null; + if (edgeName.equals(SpringLayout.NORTH)) + retVal = y; + else if (edgeName.equals(SpringLayout.WEST)) + retVal = x; + else if (edgeName.equals(SpringLayout.SOUTH)) + { + retVal = south; + if ((retVal == null) && (y != null) && (height != null)) + retVal = Spring.sum(y, height); + } + else if (edgeName.equals(SpringLayout.EAST)) + { + retVal = east; + if ((retVal == null) && (x != null) && (width != null)) + retVal = Spring.sum(x, width); + } + + return retVal; + } + + /** + * Returns the constraint for the height of the component. + * + * @return the height constraint. + */ + public Spring getHeight() + { + Spring retVal = height; + if ((retVal == null) && (y != null) && (south != null)) + { + retVal = Spring.sum(south, Spring.minus(y)); + } + return retVal; + } + + /** + * Returns the constraint for the width of the component. + * + * @return the width constraint. + */ + public Spring getWidth() + { + Spring retVal = width; + if ((retVal == null) && (x != null) && (east != null)) + { + retVal = Spring.sum(east, Spring.minus(x)); + } + return retVal; + } + + /** + * Returns the constraint for the left edge of the component. + * + * @return the left-edge constraint (== WEST). + */ + public Spring getX() + { + Spring retVal = x; + if ((retVal == null) && (width != null) && (east != null)) + { + retVal = Spring.sum(east, Spring.minus(width)); + } + return retVal; + } + + /** + * Returns the constraint for the upper edge of the component. + * + * @return the upper-edge constraint (== NORTH). + */ + public Spring getY() + { + Spring retVal = y; + if ((retVal == null) && (height != null) && (south != null)) + { + retVal = Spring.sum(south, Spring.minus(height)); + } + return retVal; + } + + /** + * Sets a constraint for the specified edge. If this leads to an + * over-constrained situation, the constraints get adjusted, so that + * the mathematics still hold true. + * + * @param edgeName the name of the edge, one of {@link #EAST}, + * {@link #WEST}, {@link NORTH} or {@link SOUTH}. + * @param s the constraint to be set. + */ + public void setConstraint(String edgeName, Spring s) + { + + if (edgeName.equals(SpringLayout.WEST)) + { + x = s; + if ((width != null) && (east != null)) + width = Spring.sum(east, Spring.minus(x)); + } + else if (edgeName.equals(SpringLayout.NORTH)) + { + y = s; + if ((height != null) && (south != null)) + height = Spring.sum(south, Spring.minus(y)); + } + else if (edgeName.equals(SpringLayout.EAST)) + { + east = s; + if ((x != null) && (width != null)) + x = Spring.sum(east, Spring.minus(width)); + } + else if (edgeName.equals(SpringLayout.SOUTH)) + { + south = s; + if ((height != null) && (y != null)) + y = Spring.sum(south, Spring.minus(height)); + } + + } + + /** + * Sets the height-constraint. + * + * @param s the constraint to be set. + */ + public void setHeight(Spring s) + { + height = s; + if ((south != null) && (y != null)) + south = Spring.sum(y, height); + + } + + /** + * Sets the width-constraint. + * + * @param s the constraint to be set. + */ + public void setWidth(Spring s) + { + width = s; + if ((east != null) && (x != null)) + east = Spring.sum(x, width); + + } + + /** + * Sets the WEST-constraint. + * + * @param s the constraint to be set. + */ + public void setX(Spring s) + { + x = s; + if ((width != null) && (east != null)) + width = Spring.sum(east, Spring.minus(x)); + + } + + /** + * Sets the NORTH-constraint. + * + * @param s the constraint to be set. + */ + public void setY(Spring s) + { + y = s; + if ((height != null) && (south != null)) + height = Spring.sum(south, Spring.minus(y)); + + } + } + + /** + * Creates a new SpringLayout. + */ + public SpringLayout() + { + + constraintsMap = new HashMap(); + } + + /** + * Adds a layout component and a constraint object to this layout. + * This method is usually only called by a {@java.awt.Container}s add + * Method. + * + * @param component the component to be added. + * @param constraint the constraint to be set. + */ + public void addLayoutComponent(Component component, Object constraint) + { + constraintsMap.put(component, constraint); + } + + + /** + * Adds a layout component and a constraint object to this layout. + * This method is usually only called by a {@java.awt.Container}s add + * Method. This method does nothing, since SpringLayout does not manage + * String-indexed components. + * + * @param component the component to be added. + * @param constraint the constraint to be set. + */ + public void addLayoutComponent(String name, Component c) + { + // do nothing here. + } + + /** + * Returns the constraint of the edge named by <code>edgeName</code>. + * + * @param c the component from which to get the constraint. + * @param edgeName the name of the edge, one of {@link #EAST}, + * {@link #WEST}, {@link NORTH} or {@link SOUTH}. + * @return the constraint of the edge <code>edgeName</code> of the + * component c. + */ + public Spring getConstraint(String edgeName, Component c) + { + Constraints constraints = getConstraints(c); + return constraints.getConstraint(edgeName); + } + + /** + * Returns the {@link Constraints} object associated with the specified + * component. + * + * @param c the component for which to determine the constraint. + * @return the {@link Constraints} object associated with the specified + * component. + */ + public SpringLayout.Constraints getConstraints(Component c) + { + Constraints constraints = (Constraints) constraintsMap.get(c); + if (constraints == null) + { + Container parent = c.getParent(); + constraints = new Constraints(); + if (parent != null) + { + constraints.setX + (Spring.constant(parent.getInsets().left)); + constraints.setY + (Spring.constant(parent.getInsets().top)); + } + else + { + constraints.setX + (Spring.constant(0)); + constraints.setY + (Spring.constant(0)); + + } + constraints.setWidth + (Spring.constant(c.getMinimumSize().width, + c.getPreferredSize().width, + c.getMaximumSize().width)); + constraints.setHeight + (Spring.constant(c.getMinimumSize().height, + c.getPreferredSize().height, + c.getMaximumSize().height)); + + constraintsMap.put(c, constraints); + + } + + return constraints; + } + + /** + * Returns the X alignment of the Container <code>p</code>. + * + * @param p the {@link java.awt.Container} for which to determine the X + * alignment. + * @return always 0.0 + */ + public float getLayoutAlignmentX(Container p) + { + return 0.0F; + } + + /** + * Returns the Y alignment of the Container <code>p</code>. + * + * @param p the {@link java.awt.Container} for which to determine the Y + * alignment. + * @return always 0.0 + */ + public float getLayoutAlignmentY(Container p) + { + return 0.0F; + } + + /** + * Recalculate a possibly cached layout. + */ + public void invalidateLayout(Container p) + { + // nothing to do here yet + } + + /** + * Lays out the container <code>p</code>. + * + * @param p the container to be laid out. + */ + public void layoutContainer(Container p) + { + + addLayoutComponent(p, new Constraints(Spring.constant(0), + Spring.constant(0))); + + int offsetX = p.getInsets().left; + int offsetY = p.getInsets().right; + + Component[] components = p.getComponents(); + for (int index = 0; index < components.length; index++) + { + Component c = components[index]; + Constraints constraints = getConstraints(c); + int x = constraints.getX().getValue(); + int y = constraints.getY().getValue(); + int width = constraints.getWidth().getValue(); + int height = constraints.getHeight().getValue(); + + c.setLocation(x + offsetX, y + offsetY); + c.setSize(width, height); + } + + } + + /** + * Calculates the maximum size of the layed out container. This + * respects the maximum sizes of all contained components. + * + * @param p the container to be laid out. + * @return the maximum size of the container. + */ + public Dimension maximumLayoutSize(Container p) + { + int maxX = 0; + int maxY = 0; + + int offsetX = p.getInsets().left; + int offsetY = p.getInsets().right; + + Component[] components = p.getComponents(); + for (int index = 0; index < components.length; index++) + { + Component c = components[index]; + Constraints constraints = getConstraints(c); + int x = constraints.getX().getMaximumValue(); + int y = constraints.getY().getMaximumValue(); + int width = constraints.getWidth().getMaximumValue(); + int height = constraints.getHeight().getMaximumValue(); + + int rightEdge = offsetX + x + width; + if (rightEdge > maxX) + maxX = rightEdge; + int bottomEdge = offsetY + y + height; + if (bottomEdge > maxY) + maxY = bottomEdge; + } + + return new Dimension(maxX, maxY); + } + + + /** + * Calculates the minimum size of the layed out container. This + * respects the minimum sizes of all contained components. + * + * @param p the container to be laid out. + * @return the minimum size of the container. + */ + public Dimension minimumLayoutSize(Container p) + { + int maxX = 0; + int maxY = 0; + + int offsetX = p.getInsets().left; + int offsetY = p.getInsets().right; + + Component[] components = p.getComponents(); + for (int index = 0; index < components.length; index++) + { + Component c = components[index]; + Constraints constraints = getConstraints(c); + int x = constraints.getX().getMinimumValue(); + int y = constraints.getY().getMinimumValue(); + int width = constraints.getWidth().getMinimumValue(); + int height = constraints.getHeight().getMinimumValue(); + + int rightEdge = offsetX + x + width; + if (rightEdge > maxX) + maxX = rightEdge; + int bottomEdge = offsetY + y + height; + if (bottomEdge > maxY) + maxY = bottomEdge; + } + + return new Dimension(maxX, maxY); + } + + /** + * Calculates the preferred size of the layed out container. This + * respects the preferred sizes of all contained components. + * + * @param p the container to be laid out. + * @return the preferred size of the container. + */ + public Dimension preferredLayoutSize(Container p) + { + int maxX = 0; + int maxY = 0; + + int offsetX = p.getInsets().left; + int offsetY = p.getInsets().right; + + Component[] components = p.getComponents(); + for (int index = 0; index < components.length; index++) + { + Component c = components[index]; + Constraints constraints = getConstraints(c); + int x = constraints.getX().getPreferredValue(); + int y = constraints.getY().getPreferredValue(); + int width = constraints.getWidth().getPreferredValue(); + int height = constraints.getHeight().getPreferredValue(); + + int rightEdge = offsetX + x + width; + if (rightEdge > maxX) + maxX = rightEdge; + int bottomEdge = offsetY + y + height; + if (bottomEdge > maxY) + maxY = bottomEdge; + } + + return new Dimension(maxX, maxY); + } + + /** + * Attaches the edge <code>e1</code> of component <code>c1</code> to + * the edge <code>e2</code> of component <code>c2</code> width the + * fixed strut <code>pad</code>. + * + * @param e1 the edge of component 1. + * @param c1 the component 1. + * @param pad the space between the components in pixels. + * @param e2 the edge of component 2. + * @param c2 the component 2. + */ + public void putConstraint(String e1, Component c1, int pad, String e2, + Component c2) + { + Constraints constraints1 = getConstraints(c1); + Constraints constraints2 = getConstraints(c2); + + Spring strut = Spring.constant(pad); + Spring otherEdge = constraints2.getConstraint(e2); + constraints1.setConstraint(e1, Spring.sum(strut, otherEdge)); + + } + + /** + * Attaches the edge <code>e1</code> of component <code>c1</code> to + * the edge <code>e2</code> of component <code>c2</code> width the + * {@link Spring} <code>s</code>. + * + * @param e1 the edge of component 1. + * @param c1 the component 1. + * @param s the space between the components as a {@link Spring} object. + * @param e2 the edge of component 2. + * @param c2 the component 2. + */ + public void putConstraint(String e1, Component c1, Spring s, String e2, + Component c2) + { + Constraints constraints1 = getConstraints(c1); + Constraints constraints2 = getConstraints(c2); + + Spring otherEdge = constraints2.getConstraint(e2); + constraints1.setConstraint(e1, Spring.sum(s, otherEdge)); + + } + + /** + * Removes a layout component. + * @param c the layout component to remove. + */ + public void removeLayoutComponent(Component c) + { + // do nothing here + } +} |