org.eclipse.swt.layout.FillLayout Maven / Gradle / Ivy

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/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.layout;

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

/**
 * FillLayout is the simplest layout class. It lays out 
 * controls in a single row or column, forcing them to be the same size. 
 * 
 * Initially, the controls will all be as tall as the tallest control, 
 * and as wide as the widest. FillLayout does not wrap, 
 * but you can specify margins and spacing. You might use it to 
 * lay out buttons in a task bar or tool bar, or to stack checkboxes 
 * in a Group. FillLayout can also be used 
 * when a Composite only has one child. For example, 
 * if a Shell has a single Group child, 
 * FillLayout will cause the Group to 
 * completely fill the Shell (if margins are 0).
 * 
 * 
 * Example code: first a FillLayout is created and
 * its type field is set, and then the layout is set into the 
 * Composite. Note that in a FillLayout,
 * children are always the same size, and they fill all available space.
 * 
 * 		FillLayout fillLayout = new FillLayout();
 * 		fillLayout.type = SWT.VERTICAL;
 * 		shell.setLayout(fillLayout);
 * 
 * 
 *
 * @see SWT Example: LayoutExample
 * @see Sample code and further information
 */
public final class FillLayout extends Layout {
	/**
	 * type specifies how controls will be positioned 
	 * within the layout.
	 *
	 * The default value is HORIZONTAL.
	 *
	 * Possible values are: 
	 *    HORIZONTAL: Position the controls horizontally from left to right
	 *    VERTICAL: Position the controls vertically from top to bottom
	 * 
	 */
	public int type = SWT.HORIZONTAL;
	
	/**
	 * marginWidth specifies the number of pixels of horizontal margin
	 * that will be placed along the left and right edges of the layout.
	 *
	 * The default value is 0.
	 * 
	 * @since 3.0
	 */
 	public int marginWidth = 0;
 	
	/**
	 * marginHeight specifies the number of pixels of vertical margin
	 * that will be placed along the top and bottom edges of the layout.
	 *
	 * The default value is 0.
	 * 
	 * @since 3.0
	 */
 	public int marginHeight = 0;
 	
 	/**
	 * spacing specifies the number of pixels between the edge of one cell
	 * and the edge of its neighbouring cell.
	 *
	 * The default value is 0.
	 * 
	 * @since 3.0
	 */
	public int spacing = 0;
	
/**
 * Constructs a new instance of this class.
 */
public FillLayout () {
}

/**
 * Constructs a new instance of this class given the type.
 *
 * @param type the type of fill layout
 * 
 * @since 2.0
 */
public FillLayout (int type) {
	this.type = type;
}

@Override
protected Point computeSize (Composite composite, int wHint, int hHint, boolean flushCache) {
	Control [] children = composite.getChildren ();
	int count = children.length;
	int maxWidth = 0, maxHeight = 0;
	for (int i=0; i 0) {
			if (type == SWT.HORIZONTAL && wHint != SWT.DEFAULT) {
				w = Math.max (0, (wHint - (count - 1) * spacing) / count);
			}
			if (type == SWT.VERTICAL && hHint != SWT.DEFAULT) {
				h = Math.max (0, (hHint - (count - 1) * spacing) / count);
			}
		}
		Point size = computeChildSize (child, w, h, flushCache);
		maxWidth = Math.max (maxWidth, size.x);
		maxHeight = Math.max (maxHeight, size.y);
	}
	int width = 0, height = 0;
	if (type == SWT.HORIZONTAL) {
		width = count * maxWidth;
		if (count != 0) width += (count - 1) * spacing;
		height = maxHeight;
	} else {
		width = maxWidth;
		height = count * maxHeight;
		if (count != 0) height += (count - 1) * spacing;
	}
	width += marginWidth * 2;
	height += marginHeight * 2;
	if (wHint != SWT.DEFAULT) width = wHint;
	if (hHint != SWT.DEFAULT) height = hHint;
	return new Point (width, height);
}

Point computeChildSize (Control control, int wHint, int hHint, boolean flushCache) {
	FillData data = (FillData)control.getLayoutData ();
	if (data == null) {
		data = new FillData ();
		control.setLayoutData (data);
	}
	Point size = null;
	if (wHint == SWT.DEFAULT && hHint == SWT.DEFAULT) {
		size = data.computeSize (control, wHint, hHint, flushCache);
	} else {
		// TEMPORARY CODE
		int trimX, trimY;
		if (control instanceof Scrollable) {
			Rectangle rect = ((Scrollable) control).computeTrim (0, 0, 0, 0);
			trimX = rect.width;
			trimY = rect.height;
		} else {
			trimX = trimY = control.getBorderWidth () * 2;
		}
		int w = wHint == SWT.DEFAULT ? wHint : Math.max (0, wHint - trimX);
		int h = hHint == SWT.DEFAULT ? hHint : Math.max (0, hHint - trimY);
		size = data.computeSize (control, w, h, flushCache);
	}
	return size;
}

@Override
protected boolean flushCache (Control control) {
	Object data = control.getLayoutData();
	if (data != null) ((FillData)data).flushCache();
	return true;
}

String getName () {
	String string = getClass ().getName ();
	int index = string.lastIndexOf ('.');
	if (index == -1) return string;
	return string.substring (index + 1, string.length ());
}

@Override
protected void layout (Composite composite, boolean flushCache) {
	Rectangle rect = composite.getClientArea ();
	Control [] children = composite.getChildren ();
	int count = children.length;
	if (count == 0) return;
	int width = rect.width - marginWidth * 2;
	int height = rect.height - marginHeight * 2;
	if (type == SWT.HORIZONTAL) {
		width -= (count - 1) * spacing;
		int x = rect.x + marginWidth, extra = width % count;
		int y = rect.y + marginHeight, cellWidth = width / count;
		for (int i=0; i