sashform.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.custom;


import org.eclipse.swt.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.*;

/**
 * The SashForm lays out its children in a Row or Column arrangement (as specified
 * by the orientation) and places a Sash between the children.
 * One child may be maximized to occupy the entire size of the SashForm.
 * The relative sizes of the children may be specfied using weights.
 *
 * <p>
 * <dl>
 * <dt><b>Styles:</b><dd>HORIZONTAL, VERTICAL
 * </dl>
 */
public class SashForm extends Composite {

	public int SASH_WIDTH = 3;

	private static final int DRAG_MINIMUM = 20;
	
	private int orientation = SWT.HORIZONTAL;
	private Sash[] sashes = new Sash[0];
	// Remember background and foreground
	// colors to determine whether to set
	// sashes to the default color (null) or
	// a specific color
	private Color background = null;
	private Color foreground = null;
	private Control[] controls = new Control[0];
	private Control maxControl = null;
	private Listener sashListener;
	private final static String LAYOUT_RATIO = "layout ratio"; //$NON-NLS-1$

/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together 
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a widget which will be the parent of the new instance (cannot be null)
 * @param style the style of widget to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 * </ul>
 *
 * @see SWT#HORIZONTAL
 * @see SWT#VERTICAL
 * @see #getStyle()
 */
public SashForm(Composite parent, int style) {
	super(parent, checkStyle(style));
	if ((style & SWT.VERTICAL) != 0){
		orientation = SWT.VERTICAL;
	}
	
	this.addListener(SWT.Resize, new Listener() {
		public void handleEvent(Event e) {
			layout(true);
		}
	});
	
	sashListener = new Listener() {
		public void handleEvent(Event e) {
			onDragSash(e);
		}
	};
}
private static int checkStyle (int style) {
	int mask = SWT.BORDER | SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT;
	return style & mask;
}
public Point computeSize (int wHint, int hHint, boolean changed) {
	checkWidget();
	Control[] cArray = getControls(true);
	if (cArray.length == 0) return new Point(wHint, hHint);
	
	int sashwidth = sashes.length > 0 ? SASH_WIDTH + sashes [0].getBorderWidth() * 2 : SASH_WIDTH;
	int width = 0;
	int height = 0;
	boolean vertical = (orientation == SWT.VERTICAL);
	if (vertical) {
		height += (cArray.length - 1) * sashwidth;
	} else {
		width += (cArray.length - 1) * sashwidth;
	}
	for (int i = 0; i < cArray.length; i++) {
		if (vertical) {
			Point size = cArray[i].computeSize(wHint, SWT.DEFAULT);
			height += size.y;	
			width = Math.max(width, size.x);
		} else {
			Point size = cArray[i].computeSize(SWT.DEFAULT, hHint);
			width += size.x;
			height = Math.max(height, size.y);
		}
	}
	if (wHint != SWT.DEFAULT) width = wHint;
	if (hHint != SWT.DEFAULT) height = hHint;
	
	return new Point(width, height);
}
/**
 * Returns SWT.HORIZONTAL if the controls in the SashForm are laid out side by side
 * or SWT.VERTICAL   if the controls in the SashForm are laid out top to bottom.
 * 
 * @return SWT.HORIZONTAL or SWT.VERTICAL
 */
public int getOrientation() {
	//checkWidget();
	return orientation;
}
/**
 * Answer the control that currently is maximized in the SashForm.  
 * This value may be null.
 * 
 * @return the control that currently is maximized or null
 */
public Control getMaximizedControl(){
	//checkWidget();
	return this.maxControl;
}
/**
 * Answer the relative weight of each child in the SashForm.  The weight represents the
 * percent of the total width (if SashForm has Horizontal orientation) or 
 * total height (if SashForm has Vertical orientation) each control occupies.
 * The weights are returned in order of the creation of the widgets (weight[0]
 * corresponds to the weight of the first child created).
 * 
 * @return the relative weight of each child
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */

public int[] getWeights() {
	checkWidget();
	Control[] cArray = getControls(false);
	int[] ratios = new int[cArray.length];
	for (int i = 0; i < cArray.length; i++) {
		Long ratio = (Long)cArray[i].getData(LAYOUT_RATIO);
		if (ratio != null) {
			ratios[i] = (int)(ratio.longValue() * 1000 >> 16);
		} else {
			ratios[i] = 200;
		}
	}
	return ratios;
}
Control[] getControls(boolean onlyVisible) {
	Control[] children = getChildren();
	Control[] result = new Control[0];
	for (int i = 0; i < children.length; i++) {
		if (children[i] instanceof Sash) continue;
		if (onlyVisible && !children[i].getVisible()) continue;

		Control[] newResult = new Control[result.length + 1];
		System.arraycopy(result, 0, newResult, 0, result.length);
		newResult[result.length] = children[i];
		result = newResult;
	}
	return result;
}
public void layout(boolean changed) {
	checkWidget();
	Rectangle area = getClientArea();
	if (area.width == 0 || area.height == 0) return;
	
	Control[] newControls = getControls(true);
	if (controls.length == 0 && newControls.length == 0) return;
	controls = newControls;
	
	if (maxControl != null && !maxControl.isDisposed()) {
		for (int i= 0; i < controls.length; i++){
			if (controls[i] != maxControl) {
				controls[i].setBounds(-200, -200, 0, 0);
			} else {
				controls[i].setBounds(area);
			}
		}
		return;
	}
	
	// keep just the right number of sashes
	if (sashes.length < controls.length - 1) {
		Sash[] newSashes = new Sash[controls.length - 1];
		System.arraycopy(sashes, 0, newSashes, 0, sashes.length);
		int sashStyle = (orientation == SWT.HORIZONTAL) ? SWT.VERTICAL : SWT.HORIZONTAL;
		if ((getStyle() & SWT.BORDER) != 0) sashStyle |= SWT.BORDER;
		for (int i = sashes.length; i < newSashes.length; i++) {
			newSashes[i] = new Sash(this, sashStyle);
			newSashes[i].setBackground(background);
			newSashes[i].setForeground(foreground);
			newSashes[i].addListener(SWT.Selection, sashListener);
		}
		sashes = newSashes;
	}
	if (sashes.length > controls.length - 1) {
		if (controls.length == 0) {
			for (int i = 0; i < sashes.length; i++) {
				sashes[i].dispose();
			}
			sashes = new Sash[0];
		} else {
			Sash[] newSashes = new Sash[controls.length - 1];
			System.arraycopy(sashes, 0, newSashes, 0, newSashes.length);
			for (int i = controls.length - 1; i < sashes.length; i++) {
				sashes[i].dispose();
			}
			sashes = newSashes;
		}
	}