Mercurial > projects > dwt-addons
diff dwtx/draw2d/AbstractHintLayout.d @ 98:95307ad235d9
Added Draw2d code, still work in progress
author | Frank Benoit <benoit@tionex.de> |
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date | Sun, 03 Aug 2008 00:52:14 +0200 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/dwtx/draw2d/AbstractHintLayout.d Sun Aug 03 00:52:14 2008 +0200 @@ -0,0 +1,128 @@ +/******************************************************************************* + * Copyright (c) 2000, 2005 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 + * Port to the D programming language: + * Frank Benoit <benoit@tionex.de> + *******************************************************************************/ +module dwtx.draw2d.AbstractHintLayout; + +import dwt.dwthelper.utils; + +import dwtx.draw2d.geometry.Dimension; +import dwtx.draw2d.AbstractLayout; +import dwtx.draw2d.IFigure; + + +/** + * The foundation for layout managers which are sensitive to width and/or height hints. + * This class will cache preferred and minimum sizes for a given set of hints. If the + * hints change in a meaningful way, the cached size is thrown out and redetermined. + * <P> + * Subclasses may be sensitive to one or both hints. By default, this class assumes both + * hints are important. Subclasses may override this behavior in {@link + * #isSensitiveHorizontally(IFigure)} and {@link #isSensitiveVertically(IFigure)}. At + * least one of these method should return <code>true</code>. + * + * @author hudsonr + * @since 2.0 + */ +public abstract class AbstractHintLayout + : AbstractLayout +{ + +private Dimension minimumSize = null; +private Dimension cachedPreferredHint; +private Dimension cachedMinimumHint; + +this(){ + cachedPreferredHint = new Dimension(-1, -1); + cachedMinimumHint = new Dimension(-1, -1); +} +/** + * Calculates the minimum size using the given width and height hints. This method is + * called from {@link #getMinimumSize(IFigure, int, int)} whenever the cached minimum size + * has been flushed. + * <P> + * By default, this method just calls {@link #getPreferredSize(IFigure, int, int)}, + * meaning minimum and preferres sizes will be the same unless this method is overridden. + * + * @param container the Figure on which this layout is installed + * @param wHint the width hint + * @param hHint the height hint + * + * @return the layout's minimum size + */ +protected Dimension calculateMinimumSize(IFigure container, int wHint, int hHint) { + return getPreferredSize(container, wHint, hHint); +} + +/** + * @see dwtx.draw2d.LayoutManager#getMinimumSize(IFigure, int, int) + */ +public Dimension getMinimumSize(IFigure container, int w, int h) { + bool flush = cachedMinimumHint.width !is w + && isSensitiveHorizontally(container); + flush |= cachedMinimumHint.height !is h + && isSensitiveVertically(container); + if (flush) { + minimumSize = null; + cachedMinimumHint.width = w; + cachedMinimumHint.height = h; + } + if (minimumSize is null) + minimumSize = calculateMinimumSize(container, w, h); + return minimumSize; +} + +/** + * @see dwtx.draw2d.LayoutManager#getPreferredSize(IFigure, int, int) + */ +public final Dimension getPreferredSize(IFigure container, int w, int h) { + bool flush = cachedPreferredHint.width !is w + && isSensitiveHorizontally(container); + flush |= cachedPreferredHint.height !is h + && isSensitiveVertically(container); + if (flush) { + preferredSize = null; + cachedPreferredHint.width = w; + cachedPreferredHint.height = h; + } + return super.getPreferredSize(container, w, h); +} + +/** + * Extends the superclass implementation to flush the cached minimum size. + * @see dwtx.draw2d.LayoutManager#invalidate() + */ +public void invalidate() { + minimumSize = null; + super.invalidate(); +} + +/** + * Returns whether this layout manager is sensitive to changes in the horizontal hint. By + * default, this method returns <code>true</code>. + * @param container the layout's container + * @return <code>true</code> if this layout is sensite to horizontal hint changes + */ +protected bool isSensitiveHorizontally(IFigure container) { + return true; +} + +/** + * Returns whether this layout manager is sensitive to changes in the vertical hint. By + * default, this method returns <code>true</code>. + * @param container the layout's container + * @return <code>true</code> if this layout is sensite to vertical hint changes + */ +protected bool isSensitiveVertically(IFigure container) { + return true; +} + +}