bundles/org.eclipse.draw2d/src/org/eclipse/draw2d/ToolbarLayout.java

/*******************************************************************************
 * Copyright (c) 2000, 2010 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.draw2d;

import java.util.List;

import org.eclipse.draw2d.geometry.Dimension;
import org.eclipse.draw2d.geometry.Insets;
import org.eclipse.draw2d.geometry.Rectangle;
import org.eclipse.draw2d.geometry.Transposer;

/**
 * Arranges figures in a single row or column. Orientation can be set to produce
 * either a row or column layout. This layout tries to fit all children within
 * the parent's client area. To do this, it compresses the children by some
 * amount, but will not compress them smaller than their minimum size. If a
 * child's preferred size is smaller than the row's or column's minor dimension,
 * the layout can be configured to stretch the child.
 */
public class ToolbarLayout extends AbstractHintLayout {

	/** Space in pixels between Figures **/
	protected int spacing;
	/** Sets whether children should "stretch" with their container **/
	protected boolean matchWidth;
	/** Orientation of layout **/
	protected boolean horizontal = false;
	/** Alignment of layout **/
	protected int minorAlignment;

	/** Constant for center alignment **/
	public static final int ALIGN_CENTER = 0;
	/** Constant for top-left alignment **/
	public static final int ALIGN_TOPLEFT = 1;
	/** Constant for bottom-right alignment **/
	public static final int ALIGN_BOTTOMRIGHT = 2;

	/** Constant for horizontal alignment **/
	public static final boolean HORIZONTAL = true;
	/** Constant for vertical alignment **/
	public static final boolean VERTICAL = false;

	/** Transposer object used in layout calculations **/
	protected Transposer transposer;
	{
		transposer = new Transposer();
		transposer.setEnabled(horizontal);
	}

	/**
	 * Constructs a vertically oriented ToolbarLayout with child spacing of 0
	 * pixels, matchWidth <code>true</code>, and {@link #ALIGN_TOPLEFT}
	 * alignment.
	 * 
	 * @since 2.0
	 */
	public ToolbarLayout() {
		spacing = 0;
		matchWidth = true;
		minorAlignment = ALIGN_TOPLEFT;
		horizontal = false;
	}

	/**
	 * Constructs a ToolbarLayout with a specified orientation. Default values
	 * are: child spacing 0 pixels, matchWidth <code>false</code>, and
	 * {@link #ALIGN_TOPLEFT} alignment.
	 * 
	 * @param isHorizontal
	 *            whether the children are oriented horizontally
	 * @since 2.0
	 */
	public ToolbarLayout(boolean isHorizontal) {
		horizontal = isHorizontal;
		transposer.setEnabled(horizontal);
		spacing = 0;
		matchWidth = false;
		minorAlignment = ALIGN_TOPLEFT;
	}

	private Dimension calculateChildrenSize(List children, int wHint,
			int hHint, boolean preferred) {
		Dimension childSize;
		IFigure child;
		int height = 0, width = 0;
		for (int i = 0; i < children.size(); i++) {
			child = (IFigure) children.get(i);
			childSize = transposer.t(preferred ? getChildPreferredSize(child,
					wHint, hHint) : getChildMinimumSize(child, wHint, hHint));
			height += childSize.height;
			width = Math.max(width, childSize.width);
		}
		return new Dimension(width, height);
	}

	/**
	 * Calculates the minimum size of the container based on the given hints. If
	 * this is a vertically-oriented Toolbar Layout, then only the widthHint is
	 * respected (which means that the children can be as tall as they desire).
	 * In this case, the minimum width is that of the widest child, and the
	 * minimum height is the sum of the minimum heights of all children, plus
	 * the spacing between them. The border and insets of the container figure
	 * are also accounted for.
	 * 
	 * @param container
	 *            the figure whose minimum size has to be calculated
	 * @param wHint
	 *            the width hint (the desired width of the container)
	 * @param hHint
	 *            the height hint (the desired height of the container)
	 * @return the minimum size of the container
	 * @see #getMinimumSize(IFigure, int, int)
	 * @since 2.1
	 */
	protected Dimension calculateMinimumSize(IFigure container, int wHint,
			int hHint) {
		Insets insets = container.getInsets();
		if (isHorizontal()) {
			wHint = -1;
			if (hHint >= 0)
				hHint = Math.max(0, hHint - insets.getHeight());
		} else {
			hHint = -1;
			if (wHint >= 0)
				wHint = Math.max(0, wHint - insets.getWidth());
		}

		List children = container.getChildren();
		Dimension minSize = calculateChildrenSize(children, wHint, hHint, false);
		// Do a second pass, if necessary
		if (wHint >= 0 && minSize.width > wHint) {
			minSize = calculateChildrenSize(children, minSize.width, hHint,
					false);
		} else if (hHint >= 0 && minSize.width > hHint) {
			minSize = calculateChildrenSize(children, wHint, minSize.width,
					false);
		}

		minSize.height += Math.max(0, children.size() - 1) * spacing;
		return transposer.t(minSize)
				.expand(insets.getWidth(), insets.getHeight())
				.union(getBorderPreferredSize(container));
	}

	/**
	 * Calculates the preferred size of the container based on the given hints.
	 * If this is a vertically-oriented Toolbar Layout, then only the widthHint
	 * is respected (which means that the children can be as tall as they
	 * desire). In this case, the preferred width is that of the widest child,
	 * and the preferred height is the sum of the preferred heights of all
	 * children, plus the spacing between them. The border and insets of the
	 * container figure are also accounted for.
	 * 
	 * @param container
	 *            the figure whose preferred size has to be calculated
	 * @param wHint
	 *            the width hint (the desired width of the container)
	 * @param hHint
	 *            the height hint (the desired height of the container)
	 * @return the preferred size of the container
	 * @see #getPreferredSize(IFigure, int, int)
	 * @since 2.0
	 */
	protected Dimension calculatePreferredSize(IFigure container, int wHint,
			int hHint) {
		Insets insets = container.getInsets();
		if (isHorizontal()) {
			wHint = -1;
			if (hHint >= 0)
				hHint = Math.max(0, hHint - insets.getHeight());
		} else {
			hHint = -1;
			if (wHint >= 0)
				wHint = Math.max(0, wHint - insets.getWidth());
		}

		List children = container.getChildren();
		Dimension prefSize = calculateChildrenSize(children, wHint, hHint, true);
		// Do a second pass, if necessary
		if (wHint >= 0 && prefSize.width > wHint) {
			prefSize = calculateChildrenSize(children, prefSize.width, hHint,
					true);
		} else if (hHint >= 0 && prefSize.width > hHint) {
			prefSize = calculateChildrenSize(children, wHint, prefSize.width,
					true);
		}

		prefSize.height += Math.max(0, children.size() - 1) * spacing;
		return transposer.t(prefSize)
				.expand(insets.getWidth(), insets.getHeight())
				.union(getBorderPreferredSize(container));
	}

	/**
	 * @param child
	 *            the figure whose minimum size is to be determined
	 * @param wHint
	 *            the width hint
	 * @param hHint
	 *            the height hint
	 * @return the given figure's minimum size
	 * @since 3.3
	 */
	protected Dimension getChildMinimumSize(IFigure child, int wHint, int hHint) {
		return child.getMinimumSize(wHint, hHint);
	}

	/**
	 * @param child
	 *            the figure whose preferred size is to be determined
	 * @param wHint
	 *            the width hint
	 * @param hHint
	 *            the height hint
	 * @return given figure's preferred size
	 * @since 3.3
	 */
	protected Dimension getChildPreferredSize(IFigure child, int wHint,
			int hHint) {
		return child.getPreferredSize(wHint, hHint);
	}

	/**
	 * Returns the minor aligment of the layout. Minor minor axis is the axis
	 * perpindicular to the overall orientation set in the contructor.
	 * 
	 * @return the minor aligment
	 */
	public int getMinorAlignment() {
		return minorAlignment;
	}

	/**
	 * @return the spacing between children
	 */
	public int getSpacing() {
		return spacing;
	}

	/**
	 * Returns <code>true</code> if stretch minor axis has been enabled. The
	 * default value is false.
	 * 
	 * @return <code>true</code> if stretch minor axis is enabled
	 */
	public boolean getStretchMinorAxis() {
		return matchWidth;
	}

	/**
	 * @return whether the orientation of the layout is horizontal
	 * @since 2.0
	 */
	public boolean isHorizontal() {
		return horizontal;
	}

	/**
	 * @see org.eclipse.draw2d.AbstractHintLayout#isSensitiveHorizontally(IFigure)
	 */
	protected boolean isSensitiveHorizontally(IFigure parent) {
		return !isHorizontal();
	}

	/**
	 * @see org.eclipse.draw2d.AbstractHintLayout#isSensitiveVertically(IFigure)
	 */
	protected boolean isSensitiveVertically(IFigure parent) {
		return isHorizontal();
	}

	/**
	 * @see org.eclipse.draw2d.LayoutManager#layout(IFigure)
	 */
	public void layout(IFigure parent) {
		List children = parent.getChildren();
		int numChildren = children.size();
		Rectangle clientArea = transposer.t(parent.getClientArea());
		int x = clientArea.x;
		int y = clientArea.y;
		int availableHeight = clientArea.height;

		Dimension prefSizes[] = new Dimension[numChildren];
		Dimension minSizes[] = new Dimension[numChildren];

		// Calculate the width and height hints. If it's a vertical
		// ToolBarLayout,
		// then ignore the height hint (set it to -1); otherwise, ignore the
		// width hint. These hints will be passed to the children of the parent
		// figure when getting their preferred size.
		int wHint = -1;
		int hHint = -1;
		if (isHorizontal()) {
			hHint = parent.getClientArea(Rectangle.SINGLETON).height;
		} else {
			wHint = parent.getClientArea(Rectangle.SINGLETON).width;
		}

		/*
		 * Calculate sum of preferred heights of all children(totalHeight).
		 * Calculate sum of minimum heights of all children(minHeight). Cache
		 * Preferred Sizes and Minimum Sizes of all children.
		 * 
		 * totalHeight is the sum of the preferred heights of all children
		 * totalMinHeight is the sum of the minimum heights of all children
		 * prefMinSumHeight is the sum of the difference between all children's
		 * preferred heights and minimum heights. (This is used as a ratio to
		 * calculate how much each child will shrink).
		 */
		IFigure child;
		int totalHeight = 0;
		int totalMinHeight = 0;
		int prefMinSumHeight = 0;

		for (int i = 0; i < numChildren; i++) {
			child = (IFigure) children.get(i);

			prefSizes[i] = transposer.t(getChildPreferredSize(child, wHint,
					hHint));
			minSizes[i] = transposer
					.t(getChildMinimumSize(child, wHint, hHint));

			totalHeight += prefSizes[i].height;
			totalMinHeight += minSizes[i].height;
		}
		totalHeight += (numChildren - 1) * spacing;
		totalMinHeight += (numChildren - 1) * spacing;
		prefMinSumHeight = totalHeight - totalMinHeight;
		/*
		 * The total amount that the children must be shrunk is the sum of the
		 * preferred Heights of the children minus Max(the available area and
		 * the sum of the minimum heights of the children).
		 * 
		 * amntShrinkHeight is the combined amount that the children must shrink
		 * amntShrinkCurrentHeight is the amount each child will shrink
		 * respectively
		 */
		int amntShrinkHeight = totalHeight
				- Math.max(availableHeight, totalMinHeight);

		if (amntShrinkHeight < 0) {
			amntShrinkHeight = 0;
		}

		for (int i = 0; i < numChildren; i++) {
			int amntShrinkCurrentHeight = 0;
			int prefHeight = prefSizes[i].height;
			int minHeight = minSizes[i].height;
			int prefWidth = prefSizes[i].width;
			int minWidth = minSizes[i].width;
			Rectangle newBounds = new Rectangle(x, y, prefWidth, prefHeight);

			child = (IFigure) children.get(i);
			if (prefMinSumHeight != 0)
				amntShrinkCurrentHeight = (prefHeight - minHeight)
						* amntShrinkHeight / (prefMinSumHeight);

			int width = Math.min(prefWidth,
					transposer.t(child.getMaximumSize()).width);
			if (matchWidth)
				width = transposer.t(child.getMaximumSize()).width;
			width = Math.max(minWidth, Math.min(clientArea.width, width));
			newBounds.width = width;

			int adjust = clientArea.width - width;
			switch (minorAlignment) {
			case ALIGN_TOPLEFT:
				adjust = 0;
				break;
			case ALIGN_CENTER:
				adjust /= 2;
				break;
			case ALIGN_BOTTOMRIGHT:
				break;
			}
			newBounds.x += adjust;
			newBounds.height -= amntShrinkCurrentHeight;
			child.setBounds(transposer.t(newBounds));

			amntShrinkHeight -= amntShrinkCurrentHeight;
			prefMinSumHeight -= (prefHeight - minHeight);
			y += newBounds.height + spacing;
		}
	}

	/**
	 * Sets the alignment of the children contained in the layout. Possible
	 * values are {@link #ALIGN_CENTER}, {@link #ALIGN_BOTTOMRIGHT} and
	 * {@link #ALIGN_TOPLEFT}.
	 * 
	 * @param align
	 *            the minor alignment
	 * @since 2.0
	 */
	public void setMinorAlignment(int align) {
		minorAlignment = align;
	}

	/**
	 * Sets the amount of space between children.
	 * 
	 * @param space
	 *            the amount of space between children
	 * @since 2.0
	 */
	public void setSpacing(int space) {
		spacing = space;
	}

	/**
	 * Sets children's width (if vertically oriented) or height (if horizontally
	 * oriented) to stretch with their container.
	 * 
	 * @deprecated use {@link #setStretchMinorAxis(boolean)}
	 * @param match
	 *            whether to stretch children
	 * @since 2.0
	 */
	public void setMatchWidth(boolean match) {
		matchWidth = match;
	}

	/**
	 * Causes children that are smaller in the dimension of the minor axis to be
	 * stretched to fill the minor axis. The minor axis is the opposite of the
	 * orientation.
	 * 
	 * @param stretch
	 *            whether to stretch children
	 * @since 2.0
	 */
	public void setStretchMinorAxis(boolean stretch) {
		matchWidth = stretch;
	}

	/**
	 * Sets the orientation of the children in the ToolbarLayout.
	 * 
	 * @param flag
	 *            whether the orientation should be vertical
	 * @since 2.0
	 */
	public void setVertical(boolean flag) {
		if (horizontal != flag)
			return;
		invalidate();
		horizontal = !flag;
		transposer.setEnabled(horizontal);
	}

}