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Diffstat (limited to 'libjava/classpath/javax/swing/SpringLayout.java')
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diff --git a/libjava/classpath/javax/swing/SpringLayout.java b/libjava/classpath/javax/swing/SpringLayout.java new file mode 100644 index 000000000..2be5189b5 --- /dev/null +++ b/libjava/classpath/javax/swing/SpringLayout.java @@ -0,0 +1,832 @@ +/* SpringLayout.java -- + Copyright (C) 2004, 2006, 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., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 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; + +/** + * 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 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; + + /** + In each axis the user can set three values, i.e. x, width, east, if all + three are set, then there's no room for manoeuvre so in those cases the + third will be described by the below spring which is calculated in terms + of the other two + */ + private Spring v; + private Spring h; + + /** + * Creates a new Constraints object. + * There is no constraint set. + */ + public Constraints() + { + x = y = height = width = east = south = v = h = 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 = v = h = 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 = v = h = null; + } + + /** + * Create a new Constraints object which tracks the indicated + * component. The x and y positions for this Constraints object + * are constant Springs created with the component's location at + * the time this constructor is called. The width and height + * of this Constraints are Springs created using + * {@link Spring#width(Component)} and {@link Spring#height(Component)}, + * respectively. + * @param component the component to track + * @since 1.5 + */ + public Constraints(Component component) + { + this(Spring.constant(component.getX()), + Spring.constant(component.getY()), + Spring.width(component), + Spring.height(component)); + } + + /** + * 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 = getY(); + else if (edgeName.equals(SpringLayout.WEST)) + retVal = getX(); + else if (edgeName.equals(SpringLayout.SOUTH)) + retVal = getSouth(); + else if (edgeName.equals(SpringLayout.EAST)) + retVal = getEast(); + return retVal; + } + + /** + * Returns the constraint for the height of the component. + * + * @return the height constraint. + */ + public Spring getHeight() + { + if (height != null) + return height; + else if ((v == null) && (y != null) && (south != null)) + v = Spring.sum(south, Spring.minus(y)); + return v; + } + + /** + * Returns the constraint for the width of the component. + * + * @return the width constraint. + */ + public Spring getWidth() + { + if (width != null) + return width; + else if ((h == null) && (x != null) && (east != null)) + h = Spring.sum(east, Spring.minus(x)); + return h; + } + + /** + * Returns the constraint for the left edge of the component. + * + * @return the left-edge constraint (== WEST). + */ + public Spring getX() + { + if (x != null) + return x; + else if ((h == null) && (width != null) && (east != null)) + h = Spring.sum(east, Spring.minus(width)); + return h; + } + + /** + * Returns the constraint for the upper edge of the component. + * + * @return the upper-edge constraint (== NORTH). + */ + public Spring getY() + { + if (y != null) + return y; + else if ((v == null) && (height != null) && (south != null)) + v = Spring.sum(south, Spring.minus(height)); + return v; + } + + /** + * Returns the constraint for the lower edge of the component. + * + * @return the lower-edge constraint (== SOUTH). + */ + public Spring getSouth() + { + if (south != null) + return south; + else if ((v == null) && (height != null) && (y != null)) + v = Spring.sum(y, height); + return v; + } + + /** + * Returns the constraint for the right edge of the component. + * + * @return the right-edge constraint (== EAST). + */ + public Spring getEast() + { + if (east != null) + return east; + else if ((h == null) && (width != null) && (x != null)) + h = Spring.sum(x, width); + return h; + } + + /** + * 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)) + setX(s); + else if (edgeName.equals(SpringLayout.NORTH)) + setY(s); + else if (edgeName.equals(SpringLayout.EAST)) + setEast(s); + else if (edgeName.equals(SpringLayout.SOUTH)) + setSouth(s); + + } + + /** + * Sets the height-constraint. + * + * @param s the constraint to be set. + */ + public void setHeight(Spring s) + { + height = s; + v = null; + if ((south != null) && (y != null) && (height != null)) + south = null; + } + + /** + * Sets the width-constraint. + * + * @param s the constraint to be set. + */ + public void setWidth(Spring s) + { + width = s; + h = null; + if ((east != null) && (x != null) && (width != null)) + east = null; + } + + /** + * Sets the WEST-constraint. + * + * @param s the constraint to be set. + */ + public void setX(Spring s) + { + x = s; + h = null; + if ((width != null) && (east != null) && (x != null)) + width = null; + } + + /** + * Sets the NORTH-constraint. + * + * @param s the constraint to be set. + */ + public void setY(Spring s) + { + y = s; + v = null; + if ((height != null) && (south != null) && (y != null)) + height = null; + } + + /** + * Sets the SOUTH-constraint. + * + * @param s the constraint to be set. + */ + public void setSouth(Spring s) + { + south = s; + v = null; + if ((height != null) && (south != null) && (y != null)) + y = null; + } + + /** + * Sets the EAST-constraint. + * + * @param s the constraint to be set. + */ + public void setEast(Spring s) + { + east = s; + h = null; + if ((width != null) && (east != null) && (x != null)) + x = null; + } + + public void dropCalcResult() + { + if (x != null) + x.setValue(Spring.UNSET); + if (y != null) + y.setValue(Spring.UNSET); + if (width != null) + width.setValue(Spring.UNSET); + if (height != null) + height.setValue(Spring.UNSET); + if (east != null) + east.setValue(Spring.UNSET); + if (south != null) + south.setValue(Spring.UNSET); + if (h != null) + h.setValue(Spring.UNSET); + if (v != null) + v.setValue(Spring.UNSET); + } + } + + /** + * 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 {@link 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 {@link java.awt.Container}s add + * method. This method does nothing, since SpringLayout does not manage + * String-indexed components. + * + * @param name the name. + * @param c the component to be added. + */ + public void addLayoutComponent(String name, Component c) + { + // do nothing here. + } + + /** + * The trick to SpringLayout is that the network of Springs needs to + * completely created before the positioning results are generated. + * + * Using the springs directly during network creation will set their values + * before the network is completed, Using Deferred Springs during creation of + * the network allows all the edges to be connected together and the network + * to be created without resolving the Springs until their results need to be + * known, at which point the network is complete and the spring addition and + * and substitution calculations will work on a complete and valid network. + * + * @author Caolan McNamara (caolanm@redhat.com) + */ + private static class DeferredSpring extends Spring + { + private SpringLayout sl; + private String edgeName; + private Component c; + + public String toString() + { + return "DeferredSpring of edge" + edgeName + " of " + "something"; + } + + public DeferredSpring(SpringLayout s, String edge, Component component) + { + sl = s; + edgeName = edge; + c = component; + } + + private Spring resolveSpring() + { + return sl.getConstraints(c).getConstraint(edgeName); + } + + public int getMaximumValue() + { + return resolveSpring().getMaximumValue(); + } + + public int getMinimumValue() + { + return resolveSpring().getMinimumValue(); + } + + public int getPreferredValue() + { + return resolveSpring().getPreferredValue(); + } + + public int getValue() + { + int nRet = resolveSpring().getValue(); + if (nRet == Spring.UNSET) + nRet = getPreferredValue(); + return nRet; + } + + public void setValue(int size) + { + resolveSpring().setValue(size); + } + } + + private abstract static class DeferredDimension extends Spring + { + private int value; + + public DeferredDimension() + { + value = Spring.UNSET; + } + + public void setValue(int val) + { + value = val; + } + + public int getValue() + { + if (value == Spring.UNSET) + return getPreferredValue(); + return value; + } + } + + private static class DeferredWidth extends DeferredDimension + { + private Component c; + + + public DeferredWidth(Component component) + { + c = component; + } + + public String toString() + { + return "DeferredWidth of " + "something"; + } + + //clip max to a value we can do meaningful calculation with + public int getMaximumValue() + { + int widget_width = c.getMaximumSize().width; + return Math.min(Short.MAX_VALUE, widget_width); + } + + public int getMinimumValue() + { + return c.getMinimumSize().width; + } + + public int getPreferredValue() + { + return c.getPreferredSize().width; + } + } + + private static class DeferredHeight extends DeferredDimension + { + private Component c; + + public String toString() + { + return "DeferredHeight of " + "something"; + } + + public DeferredHeight(Component component) + { + c = component; + } + + //clip max to a value we can do meaningful calculations with it + public int getMaximumValue() + { + int widget_height = c.getMaximumSize().height; + return Math.min(Short.MAX_VALUE, widget_height); + } + + public int getMinimumValue() + { + return c.getMinimumSize().height; + } + + public int getPreferredValue() + { + return c.getPreferredSize().height; + } + } + + /** + * 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) + { + return new DeferredSpring(this, edgeName, c); + } + + /** + * 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) + { + constraints = new Constraints(); + + constraints.setWidth(new DeferredWidth(c)); + constraints.setHeight(new DeferredHeight(c)); + constraints.setX(Spring.constant(0)); + constraints.setY(Spring.constant(0)); + + 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 + } + + private Constraints initContainer(Container p) + { + Constraints c = getConstraints(p); + + c.setX(Spring.constant(0)); + c.setY(Spring.constant(0)); + c.setWidth(null); + c.setHeight(null); + if (c.getEast() == null) + c.setEast(Spring.constant(0, 0, Integer.MAX_VALUE)); + if (c.getSouth() == null) + c.setSouth(Spring.constant(0, 0, Integer.MAX_VALUE)); + + return c; + } + + /** + * Lays out the container <code>p</code>. + * + * @param p the container to be laid out. + */ + public void layoutContainer(Container p) + { + java.awt.Insets insets = p.getInsets(); + + Component[] components = p.getComponents(); + + Constraints cs = initContainer(p); + cs.dropCalcResult(); + + for (int index = 0 ; index < components.length; index++) + { + Component c = components[index]; + getConstraints(c).dropCalcResult(); + } + + int offsetX = p.getInsets().left; + int offsetY = p.getInsets().right; + + cs.getX().setValue(0); + cs.getY().setValue(0); + cs.getWidth().setValue(p.getWidth() - offsetX - insets.right); + cs.getHeight().setValue(p.getHeight() - offsetY - insets.bottom); + + 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.setBounds(x + offsetX, y + offsetY, 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) + { + java.awt.Insets insets = p.getInsets(); + + Constraints cs = initContainer(p); + + int maxX = cs.getWidth().getMaximumValue() + insets.left + insets.right; + int maxY = cs.getHeight().getMaximumValue() + insets.top + insets.bottom; + + 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) + { + java.awt.Insets insets = p.getInsets(); + + Constraints cs = initContainer(p); + + int maxX = cs.getWidth().getMinimumValue() + insets.left + insets.right; + int maxY = cs.getHeight().getMinimumValue() + insets.top + insets.bottom; + + 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) + { + java.awt.Insets insets = p.getInsets(); + + Constraints cs = initContainer(p); + + int maxX = cs.getWidth().getPreferredValue() + insets.left + insets.right; + int maxY = cs.getHeight().getPreferredValue() + insets.top + insets.bottom; + + 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) + { + putConstraint(e1, c1, Spring.constant(pad), e2, c2); + } + + /** + * 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); + + Spring otherEdge = getConstraint(e2, c2); + 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 + } +} |