user/src/com/google/gwt/user/client/ui/SplitLayoutPanel.java - gwt - Git at Google

 /*
  * Copyright 2009 Google Inc.
  *
  * 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.google.gwt.user.client.ui;

 import com.google.gwt.dom.client.Document;
 import com.google.gwt.dom.client.Style.Unit;
 import com.google.gwt.user.client.Command;
 import com.google.gwt.user.client.DeferredCommand;
 import com.google.gwt.user.client.Event;

 /**
  * A panel that adds user-positioned splitters between each of its child
  * widgets.
  *
  * <p>
  * This panel is used in the same way as {@link DockLayoutPanel}, except that
  * its children's sizes are always specified in {@link Unit#PX} units, and each
  * pair of child widgets has a splitter between them that the user can drag.
  * </p>
  *
  * <p>
  * This widget will <em>only</em> work in standards mode, which requires
  * that the HTML page in which it is run have an explicit &lt;!DOCTYPE&gt;
  * declaration.
  * </p>
  *
  * <p>
  * NOTE: This class is still very new, and its interface may change without
  * warning. Use at your own risk.
  * </p>
  *
  * <p>
  * <h3>Example</h3>
  * {@example com.google.gwt.examples.SplitLayoutPanelExample}
  * </p>
  *
  * TODO(jgw):
  * - RTL Support.
  * - implement insert().
  * - Come up with a decent way to specify splitter style and size.
  */
 public class SplitLayoutPanel extends DockLayoutPanel {

   private class HSplitter extends Splitter {
     public HSplitter(Widget target, boolean reverse) {
       super(target, reverse);
       getElement().getStyle().setPropertyPx("width", 4);
       setStyleName("LayoutPanel-HDragger");
     }

     @Override
     protected int getAbsolutePosition() {
       return getAbsoluteLeft();
     }

     @Override
     protected int getEventPosition(Event event) {
       return event.getClientX();
     }

     @Override
     protected int getTargetPosition() {
       return target.getAbsoluteLeft();
     }

     @Override
     protected int getTargetSize() {
       return target.getOffsetWidth();
     }
   }

   private abstract class Splitter extends Widget {
     protected final Widget target;

     private int offset;
     private boolean mouseDown;
     private Command layoutCommand;

     private final boolean reverse;
     private int minSize;

     public Splitter(Widget target, boolean reverse) {
       this.target = target;
       this.reverse = reverse;

       setElement(Document.get().createDivElement());
       sinkEvents(Event.ONMOUSEDOWN | Event.ONMOUSEUP | Event.ONMOUSEMOVE
           | Event.ONDBLCLICK);
     }

     @Override
     public void onBrowserEvent(Event event) {
       switch (event.getTypeInt()) {
         case Event.ONMOUSEDOWN:
           mouseDown = true;
           offset = getEventPosition(event) - getAbsolutePosition();
           Event.setCapture(getElement());
           event.preventDefault();
           break;

         case Event.ONMOUSEUP:
           mouseDown = false;
           Event.releaseCapture(getElement());
           event.preventDefault();
           break;

         case Event.ONMOUSEMOVE:
           if (mouseDown) {
             int size;
             if (reverse) {
               size = getTargetPosition() + getTargetSize()
                   - getEventPosition(event) - offset;
             } else {
               size = getEventPosition(event) - getTargetPosition() - offset;
             }

             setAssociatedWidgetSize(size);
             event.preventDefault();
           }
           break;
       }
     }

     public void setMinSize(int minSize) {
       this.minSize = minSize;
       LayoutData layout = (LayoutData) target.getLayoutData();

       // Try resetting the associated widget's size, which will enforce the new
       // minSize value.
       setAssociatedWidgetSize((int) layout.size);
     }

     protected abstract int getAbsolutePosition();

     protected abstract int getEventPosition(Event event);

     protected abstract int getTargetPosition();

     protected abstract int getTargetSize();

     private void setAssociatedWidgetSize(int size) {
       if (size < minSize) {
         size = minSize;
       }

       LayoutData layout = (LayoutData) target.getLayoutData();
       if (size == layout.size) {
         return;
       }

       layout.size = size;

       // Defer actually updating the layout, so that if we receive many
       // mouse events before layout/paint occurs, we'll only update once.
       if (layoutCommand == null) {
         layoutCommand = new Command() {
           public void execute() {
             layoutCommand = null;
             layout();
           }
         };
         DeferredCommand.addCommand(layoutCommand);
       }
     }
   }

   private class VSplitter extends Splitter {
     public VSplitter(Widget target, boolean reverse) {
       super(target, reverse);
       getElement().getStyle().setPropertyPx("height", 4);
       setStyleName("LayoutPanel-VDragger");
     }

     @Override
     protected int getAbsolutePosition() {
       return getAbsoluteTop();
     }

     @Override
     protected int getEventPosition(Event event) {
       return event.getClientY();
     }

     @Override
     protected int getTargetPosition() {
       return target.getAbsoluteTop();
     }

     @Override
     protected int getTargetSize() {
       return target.getOffsetHeight();
     }
   }

   private static final int SPLITTER_SIZE = 4;

   public SplitLayoutPanel() {
     super(Unit.PX);
   }

   @Override
   public void insert(Widget child, Direction direction, double size, Widget before) {
     super.insert(child, direction, size, before);
     if (direction != Direction.CENTER) {
       insertSplitter(before);
     }
   }

   @Override
   public boolean remove(Widget child) {
     assert !(child instanceof Splitter) : "Splitters may not be directly removed";

     if (super.remove(child)) {
       // Remove the associated splitter, if any.
       int idx = getWidgetIndex(child);
       if (idx < getWidgetCount() - 1) {
         remove(idx + 1);
       }
       return true;
     }
     return false;
   }

   /**
    * Sets the minimum allowable size for the given widget.
    *
    * <p>
    * Its assocated splitter cannot be dragged to a position that would make it
    * smaller than this size. This method has no effect for the
    * {@link Direction#CENTER} widget.
    * </p>
    *
    * @param child the child whose minimum size will be set
    * @param minSize the minimum size for this widget
    */
   public void setWidgetMinSize(Widget child, int minSize) {
     Splitter splitter = getAssociatedSplitter(child);
     splitter.setMinSize(minSize);
   }

   private void insertSplitter(Widget before) {
     assert getChildren().size() > 0 : "Can't add a splitter before any children";
     assert getCenter() == null : "Can't add a splitter after the CENTER widget";

     Widget lastChild = getChildren().get(getChildren().size() - 1);
     LayoutData lastChildLayout = (LayoutData) lastChild.getLayoutData();
     Splitter splitter = null;
     switch (lastChildLayout.direction) {
       case WEST:
         splitter = new HSplitter(lastChild, false);
         break;
       case EAST:
         splitter = new HSplitter(lastChild, true);
         break;
       case NORTH:
         splitter = new VSplitter(lastChild, false);
         break;
       case SOUTH:
         splitter = new VSplitter(lastChild, true);
         break;
       default:
         assert false : "Unexpected direction";
     }

     super.insert(splitter, lastChildLayout.direction, SPLITTER_SIZE, before);
   }

   private Splitter getAssociatedSplitter(Widget child) {
     // If a widget has a next sibling, it must be a splitter, because the only
     // widget that *isn't* followed by a splitter must be the CENTER, which has
     // no associated splitter.
     int idx = getWidgetIndex(child);
     if (idx < getWidgetCount() - 2) {
       Widget splitter = getWidget(idx + 1);
       assert splitter instanceof Splitter : "Expected child widget to be splitter";
       return (Splitter) splitter;
     }
     return null;
   }
 }
	/*
	* Copyright 2009 Google Inc.
	*
	* 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.google.gwt.user.client.ui;

	import com.google.gwt.dom.client.Document;
	import com.google.gwt.dom.client.Style.Unit;
	import com.google.gwt.user.client.Command;
	import com.google.gwt.user.client.DeferredCommand;
	import com.google.gwt.user.client.Event;

	/**
	* A panel that adds user-positioned splitters between each of its child
	* widgets.
	*
	* <p>
	* This panel is used in the same way as {@link DockLayoutPanel}, except that
	* its children's sizes are always specified in {@link Unit#PX} units, and each
	* pair of child widgets has a splitter between them that the user can drag.
	* </p>
	*
	* <p>
	* This widget will <em>only</em> work in standards mode, which requires
	* that the HTML page in which it is run have an explicit <!DOCTYPE>
	* declaration.
	* </p>
	*
	* <p>
	* NOTE: This class is still very new, and its interface may change without
	* warning. Use at your own risk.
	* </p>
	*
	* <p>
	* <h3>Example</h3>
	* {@example com.google.gwt.examples.SplitLayoutPanelExample}
	* </p>
	*
	* TODO(jgw):
	* - RTL Support.
	* - implement insert().
	* - Come up with a decent way to specify splitter style and size.
	*/
	public class SplitLayoutPanel extends DockLayoutPanel {

	private class HSplitter extends Splitter {
	public HSplitter(Widget target, boolean reverse) {
	super(target, reverse);
	getElement().getStyle().setPropertyPx("width", 4);
	setStyleName("LayoutPanel-HDragger");
	}

	@Override
	protected int getAbsolutePosition() {
	return getAbsoluteLeft();
	}

	@Override
	protected int getEventPosition(Event event) {
	return event.getClientX();
	}

	@Override
	protected int getTargetPosition() {
	return target.getAbsoluteLeft();
	}

	@Override
	protected int getTargetSize() {
	return target.getOffsetWidth();
	}
	}

	private abstract class Splitter extends Widget {
	protected final Widget target;

	private int offset;
	private boolean mouseDown;
	private Command layoutCommand;

	private final boolean reverse;
	private int minSize;

	public Splitter(Widget target, boolean reverse) {
	this.target = target;
	this.reverse = reverse;

	setElement(Document.get().createDivElement());
	sinkEvents(Event.ONMOUSEDOWN \| Event.ONMOUSEUP \| Event.ONMOUSEMOVE
	\| Event.ONDBLCLICK);
	}

	@Override
	public void onBrowserEvent(Event event) {
	switch (event.getTypeInt()) {
	case Event.ONMOUSEDOWN:
	mouseDown = true;
	offset = getEventPosition(event) - getAbsolutePosition();
	Event.setCapture(getElement());
	event.preventDefault();
	break;

	case Event.ONMOUSEUP:
	mouseDown = false;
	Event.releaseCapture(getElement());
	event.preventDefault();
	break;

	case Event.ONMOUSEMOVE:
	if (mouseDown) {
	int size;
	if (reverse) {
	size = getTargetPosition() + getTargetSize()
	- getEventPosition(event) - offset;
	} else {
	size = getEventPosition(event) - getTargetPosition() - offset;
	}

	setAssociatedWidgetSize(size);
	event.preventDefault();
	}
	break;
	}
	}

	public void setMinSize(int minSize) {
	this.minSize = minSize;
	LayoutData layout = (LayoutData) target.getLayoutData();

	// Try resetting the associated widget's size, which will enforce the new
	// minSize value.
	setAssociatedWidgetSize((int) layout.size);
	}

	protected abstract int getAbsolutePosition();

	protected abstract int getEventPosition(Event event);

	protected abstract int getTargetPosition();

	protected abstract int getTargetSize();

	private void setAssociatedWidgetSize(int size) {
	if (size < minSize) {
	size = minSize;
	}

	LayoutData layout = (LayoutData) target.getLayoutData();
	if (size == layout.size) {
	return;
	}

	layout.size = size;

	// Defer actually updating the layout, so that if we receive many
	// mouse events before layout/paint occurs, we'll only update once.
	if (layoutCommand == null) {
	layoutCommand = new Command() {
	public void execute() {
	layoutCommand = null;
	layout();
	}
	};
	DeferredCommand.addCommand(layoutCommand);
	}
	}
	}

	private class VSplitter extends Splitter {
	public VSplitter(Widget target, boolean reverse) {
	super(target, reverse);
	getElement().getStyle().setPropertyPx("height", 4);
	setStyleName("LayoutPanel-VDragger");
	}

	@Override
	protected int getAbsolutePosition() {
	return getAbsoluteTop();
	}

	@Override
	protected int getEventPosition(Event event) {
	return event.getClientY();
	}

	@Override
	protected int getTargetPosition() {
	return target.getAbsoluteTop();
	}

	@Override
	protected int getTargetSize() {
	return target.getOffsetHeight();
	}
	}

	private static final int SPLITTER_SIZE = 4;

	public SplitLayoutPanel() {
	super(Unit.PX);
	}

	@Override
	public void insert(Widget child, Direction direction, double size, Widget before) {
	super.insert(child, direction, size, before);
	if (direction != Direction.CENTER) {
	insertSplitter(before);
	}
	}

	@Override
	public boolean remove(Widget child) {
	assert !(child instanceof Splitter) : "Splitters may not be directly removed";

	if (super.remove(child)) {
	// Remove the associated splitter, if any.
	int idx = getWidgetIndex(child);
	if (idx < getWidgetCount() - 1) {
	remove(idx + 1);
	}
	return true;
	}
	return false;
	}

	/**
	* Sets the minimum allowable size for the given widget.
	*
	* <p>
	* Its assocated splitter cannot be dragged to a position that would make it
	* smaller than this size. This method has no effect for the
	* {@link Direction#CENTER} widget.
	* </p>
	*
	* @param child the child whose minimum size will be set
	* @param minSize the minimum size for this widget
	*/
	public void setWidgetMinSize(Widget child, int minSize) {
	Splitter splitter = getAssociatedSplitter(child);
	splitter.setMinSize(minSize);
	}

	private void insertSplitter(Widget before) {
	assert getChildren().size() > 0 : "Can't add a splitter before any children";
	assert getCenter() == null : "Can't add a splitter after the CENTER widget";

	Widget lastChild = getChildren().get(getChildren().size() - 1);
	LayoutData lastChildLayout = (LayoutData) lastChild.getLayoutData();
	Splitter splitter = null;
	switch (lastChildLayout.direction) {
	case WEST:
	splitter = new HSplitter(lastChild, false);
	break;
	case EAST:
	splitter = new HSplitter(lastChild, true);
	break;
	case NORTH:
	splitter = new VSplitter(lastChild, false);
	break;
	case SOUTH:
	splitter = new VSplitter(lastChild, true);
	break;
	default:
	assert false : "Unexpected direction";
	}

	super.insert(splitter, lastChildLayout.direction, SPLITTER_SIZE, before);
	}

	private Splitter getAssociatedSplitter(Widget child) {
	// If a widget has a next sibling, it must be a splitter, because the only
	// widget that isn't followed by a splitter must be the CENTER, which has
	// no associated splitter.
	int idx = getWidgetIndex(child);
	if (idx < getWidgetCount() - 2) {
	Widget splitter = getWidget(idx + 1);
	assert splitter instanceof Splitter : "Expected child widget to be splitter";
	return (Splitter) splitter;
	}
	return null;
	}
	}