1 /******************************************************************************* 2 * Copyright (c) 2000, 2008 IBM Corporation and others. 3 * All rights reserved. This program and the accompanying materials 4 * are made available under the terms of the Eclipse Public License v1.0 5 * which accompanies this distribution, and is available at 6 * http://www.eclipse.org/legal/epl-v10.html 7 * 8 * Contributors: 9 * IBM Corporation - initial API and implementation 10 * Port to the D programming language: 11 * Frank Benoit <benoit@tionex.de> 12 *******************************************************************************/ 13 module org.eclipse.swt.widgets.Layout; 14 15 import java.lang.all; 16 17 18 import org.eclipse.swt.graphics.Point; 19 import org.eclipse.swt.widgets.Control; 20 import org.eclipse.swt.widgets.Composite; 21 22 /** 23 * A layout controls the position and size 24 * of the children of a composite widget. 25 * This class is the abstract base class for 26 * layouts. 27 * 28 * @see Composite#setLayout(Layout) 29 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> 30 */ 31 public abstract class Layout { 32 33 /** 34 * Computes and returns the size of the specified 35 * composite's client area according to this layout. 36 * <p> 37 * This method computes the size that the client area 38 * of the composite must be in order to position all 39 * children at their preferred size inside the 40 * composite according to the layout algorithm 41 * encoded by this layout. 42 * </p> 43 * <p> 44 * When a width or height hint is supplied, it is 45 * used to constrain the result. For example, if a 46 * width hint is provided that is less than the 47 * width of the client area, the layout may choose 48 * to wrap and increase height, clip, overlap, or 49 * otherwise constrain the children. 50 * </p> 51 * 52 * @param composite a composite widget using this layout 53 * @param wHint width (<code>SWT.DEFAULT</code> for preferred size) 54 * @param hHint height (<code>SWT.DEFAULT</code> for preferred size) 55 * @param flushCache <code>true</code> means flush cached layout values 56 * @return a point containing the computed size (width, height) 57 * 58 * @see #layout 59 * @see Control#getBorderWidth 60 * @see Control#getBounds 61 * @see Control#getSize 62 * @see Control#pack(boolean) 63 * @see "computeTrim, getClientArea for controls that implement them" 64 */ 65 abstract Point computeSize (Composite composite, int wHint, int hHint, bool flushCache); 66 67 /** 68 * Instruct the layout to flush any cached values 69 * associated with the control specified in the argument 70 * <code>control</code>. 71 * 72 * @param control a control managed by this layout 73 * @return true if the Layout has flushed all cached information associated with control 74 * 75 * @since 3.1 76 */ 77 bool flushCache (Control control) { 78 return false; 79 } 80 81 /** 82 * Lays out the children of the specified composite 83 * according to this layout. 84 * <p> 85 * This method positions and sizes the children of a 86 * composite using the layout algorithm encoded by this 87 * layout. Children of the composite are positioned in 88 * the client area of the composite. The position of 89 * the composite is not altered by this method. 90 * </p> 91 * <p> 92 * When the flush cache hint is true, the layout is 93 * instructed to flush any cached values associated 94 * with the children. Typically, a layout will cache 95 * the preferred sizes of the children to avoid the 96 * expense of computing these values each time the 97 * widget is laid out. 98 * </p> 99 * <p> 100 * When layout is triggered explicitly by the programmer 101 * the flush cache hint is true. When layout is triggered 102 * by a resize, either caused by the programmer or by the 103 * user, the hint is false. 104 * </p> 105 * 106 * @param composite a composite widget using this layout 107 * @param flushCache <code>true</code> means flush cached layout values 108 */ 109 abstract void layout (Composite composite, bool flushCache); 110 }