path: root/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/layout/GridData.java

/*******************************************************************************
 * Copyright (c) 2000, 2018 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * 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.*;

/**
 * <code>GridData</code> is the layout data object associated with
 * <code>GridLayout</code>. To set a <code>GridData</code> object into a
 * control, you use the <code>Control.setLayoutData(Object)</code> method.
 * <p>
 * There are two ways to create a <code>GridData</code> object with certain
 * fields set. The first is to set the fields directly, like this:</p>
 * <pre>
 * 		GridData gridData = new GridData();
 * 		gridData.horizontalAlignment = GridData.FILL;
 * 		gridData.grabExcessHorizontalSpace = true;
 * 		button1.setLayoutData(gridData);
 *
 * 		gridData = new GridData();
 * 		gridData.horizontalAlignment = GridData.FILL;
 * 		gridData.verticalAlignment = GridData.FILL;
 * 		gridData.grabExcessHorizontalSpace = true;
 * 		gridData.grabExcessVerticalSpace = true;
 * 		gridData.horizontalSpan = 2;
 * 		button2.setLayoutData(gridData);
 * </pre>
 * The second is to take advantage of <code>GridData</code> convenience constructors, for example:
 * <pre>
 *      button1.setLayoutData(new GridData (SWT.FILL, SWT.CENTER, true, false));
 *      button2.setLayoutData(new GridData (SWT.FILL, SWT.FILL, true, true, 2, 1));
 * </pre>
 * <p>
 * NOTE: Do not reuse <code>GridData</code> objects. Every control in a
 * <code>Composite</code> that is managed by a <code>GridLayout</code>
 * must have a unique <code>GridData</code> object. If the layout data
 * for a control in a <code>GridLayout</code> is null at layout time,
 * a unique <code>GridData</code> object is created for it.
 * </p>
 *
 * @see GridLayout
 * @see Control#setLayoutData
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */
public final class GridData {
	/**
	 * verticalAlignment specifies how controls will be positioned
	 * vertically within a cell.
	 *
	 * The default value is CENTER.
	 *
	 * Possible values are: <ul>
	 *    <li>SWT.BEGINNING (or SWT.TOP): Position the control at the top of the cell</li>
	 *    <li>SWT.CENTER: Position the control in the vertical center of the cell</li>
	 *    <li>SWT.END (or SWT.BOTTOM): Position the control at the bottom of the cell</li>
	 *    <li>SWT.FILL: Resize the control to fill the cell vertically</li>
	 * </ul>
	 */
	public int verticalAlignment = CENTER;

	/**
	 * horizontalAlignment specifies how controls will be positioned
	 * horizontally within a cell.
	 *
	 * The default value is BEGINNING.
	 *
	 * Possible values are: <ul>
	 *    <li>SWT.BEGINNING (or SWT.LEFT): Position the control at the left of the cell</li>
	 *    <li>SWT.CENTER: Position the control in the horizontal center of the cell</li>
	 *    <li>SWT.END (or SWT.RIGHT): Position the control at the right of the cell</li>
	 *    <li>SWT.FILL: Resize the control to fill the cell horizontally</li>
	 * </ul>
	 */
	public int horizontalAlignment = BEGINNING;

	/**
	 * widthHint specifies the preferred width in points. This value
	 * is the wHint passed into Control.computeSize(int, int, boolean)
	 * to determine the preferred size of the control.
	 *
	 * The default value is SWT.DEFAULT.
	 *
	 * @see Control#computeSize(int, int, boolean)
	 */
	public int widthHint = SWT.DEFAULT;

	/**
	 * heightHint specifies the preferred height in points. This value
	 * is the hHint passed into Control.computeSize(int, int, boolean)
	 * to determine the preferred size of the control.
	 *
	 * The default value is SWT.DEFAULT.
	 *
	 * @see Control#computeSize(int, int, boolean)
	 */
	public int heightHint = SWT.DEFAULT;

	/**
	 * horizontalIndent specifies the number of points of indentation
	 * that will be placed along the left side of the cell.
	 *
	 * The default value is 0.
	 */
	public int horizontalIndent = 0;

	/**
	 * verticalIndent specifies the number of points of indentation
	 * that will be placed along the top side of the cell.
	 *
	 * The default value is 0.
	 *
	 * @since 3.1
	 */
	public int verticalIndent = 0;

	/**
	 * horizontalSpan specifies the number of column cells that the control
	 * will take up.
	 *
	 * The default value is 1.
	 */
	public int horizontalSpan = 1;

	/**
	 * verticalSpan specifies the number of row cells that the control
	 * will take up.
	 *
	 * The default value is 1.
	 */
	public int verticalSpan = 1;

	/**
	 * <p>grabExcessHorizontalSpace specifies whether the width of the cell
	 * changes depending on the size of the parent Composite.  If
	 * grabExcessHorizontalSpace is <code>true</code>, the following rules
	 * apply to the width of the cell:</p>
	 * <ul>
	 * <li>If extra horizontal space is available in the parent, the cell will
	 * grow to be wider than its preferred width.  The new width
	 * will be "preferred width + delta" where delta is the extra
	 * horizontal space divided by the number of grabbing columns.</li>
	 * <li>If there is not enough horizontal space available in the parent, the
	 * cell will shrink until it reaches its minimum width as specified by
	 * GridData.minimumWidth. The new width will be the maximum of
	 * "minimumWidth" and "preferred width - delta", where delta is
	 * the amount of space missing divided by the number of grabbing columns.</li>
	 * <li>If the parent is packed, the cell will be its preferred width
	 * as specified by GridData.widthHint.</li>
	 * <li>If the control spans multiple columns and there are no other grabbing
	 * controls in any of the spanned columns, the last column in the span will
	 * grab the extra space.  If there is at least one other grabbing control
	 * in the span, the grabbing will be spread over the columns already
	 * marked as grabExcessHorizontalSpace.</li>
	 * </ul>
	 *
	 * <p>The default value is false.</p>
	 *
	 * @see GridData#minimumWidth
	 * @see GridData#widthHint
	 */
	public boolean grabExcessHorizontalSpace = false;

	/**
	 * <p>grabExcessVerticalSpace specifies whether the height of the cell
	 * changes depending on the size of the parent Composite.  If
	 * grabExcessVerticalSpace is <code>true</code>, the following rules
	 * apply to the height of the cell:</p>
	 * <ul>
	 * <li>If extra vertical space is available in the parent, the cell will
	 * grow to be taller than its preferred height.  The new height
	 * will be "preferred height + delta" where delta is the extra
	 * vertical space divided by the number of grabbing rows.</li>
	 * <li>If there is not enough vertical space available in the parent, the
	 * cell will shrink until it reaches its minimum height as specified by
	 * GridData.minimumHeight. The new height will be the maximum of
	 * "minimumHeight" and "preferred height - delta", where delta is
	 * the amount of space missing divided by the number of grabbing rows.</li>
	 * <li>If the parent is packed, the cell will be its preferred height
	 * as specified by GridData.heightHint.</li>
	 * <li>If the control spans multiple rows and there are no other grabbing
	 * controls in any of the spanned rows, the last row in the span will
	 * grab the extra space.  If there is at least one other grabbing control
	 * in the span, the grabbing will be spread over the rows already
	 * marked as grabExcessVerticalSpace.</li>
	 * </ul>
	 *
	 * <p>The default value is false.</p>
	 *
	 * @see GridData#minimumHeight
	 * @see GridData#heightHint
	 */
	public boolean grabExcessVerticalSpace = false;

	/**
	 * minimumWidth specifies the minimum width in points.  This value
	 * applies only if grabExcessHorizontalSpace is true. A value of
	 * SWT.DEFAULT means that the minimum width will be the result
	 * of Control.computeSize(int, int, boolean) where wHint is
	 * determined by GridData.widthHint.
	 *
	 * The default value is 0.
	 *
	 * @since 3.1
	 * @see Control#computeSize(int, int, boolean)
	 * @see GridData#widthHint
	 */
	public int minimumWidth = 0;

	/**
	 * minimumHeight specifies the minimum height in points.  This value
	 * applies only if grabExcessVerticalSpace is true.  A value of
	 * SWT.DEFAULT means that the minimum height will be the result
	 * of Control.computeSize(int, int, boolean) where hHint is
	 * determined by GridData.heightHint.
	 *
	 * The default value is 0.
	 *
	 * @since 3.1
	 * @see Control#computeSize(int, int, boolean)
	 * @see GridData#heightHint
	 */
	public int minimumHeight = 0;

	/**
	 * exclude informs the layout to ignore this control when sizing
	 * and positioning controls.  If this value is <code>true</code>,
	 * the size and position of the control will not be managed by the
	 * layout.  If this	value is <code>false</code>, the size and
	 * position of the control will be computed and assigned.
	 *
	 * The default value is <code>false</code>.
	 *
	 * @since 3.1
	 */
	public boolean exclude = false;

	/**
	 * Value for horizontalAlignment or verticalAlignment.
	 * Position the control at the top or left of the cell.
	 * Not recommended. Use SWT.BEGINNING, SWT.TOP or SWT.LEFT instead.
	 */
	public static final int BEGINNING = SWT.BEGINNING;

	/**
	 * Value for horizontalAlignment or verticalAlignment.
	 * Position the control in the vertical or horizontal center of the cell
	 * Not recommended. Use SWT.CENTER instead.
	 */
	public static final int CENTER = 2;

	/**
	 * Value for horizontalAlignment or verticalAlignment.
	 * Position the control at the bottom or right of the cell
	 * Not recommended. Use SWT.END, SWT.BOTTOM or SWT.RIGHT instead.
	 */
	public static final int END = 3;

	/**
	 * Value for horizontalAlignment or verticalAlignment.
	 * Resize the control to fill the cell horizontally or vertically.
	 * Not recommended. Use SWT.FILL instead.
	 */
	public static final int FILL = SWT.FILL;

	/**
	 * Style bit for <code>new GridData(int)</code>.
	 * Position the control at the top of the cell.
	 * Not recommended. Use
	 * <code>new GridData(int, SWT.BEGINNING, boolean, boolean)</code>
	 * instead.
	 */
	public static final int VERTICAL_ALIGN_BEGINNING =  1 << 1;

	/**
	 * Style bit for <code>new GridData(int)</code> to position the
	 * control in the vertical center of the cell.
	 * Not recommended. Use
	 * <code>new GridData(int, SWT.CENTER, boolean, boolean)</code>
	 * instead.
	 */
	public static final int VERTICAL_ALIGN_CENTER = 1 << 2;

	/**
	 * Style bit for <code>new GridData(int)</code> to position the
	 * control at the bottom of the cell.
	 * Not recommended. Use
	 * <code>new GridData(int, SWT.END, boolean, boolean)</code>
	 * instead.
	 */
	public static final int VERTICAL_ALIGN_END = 1 << 3;

	/**
	 * Style bit for <code>new GridData(int)</code> to resize the
	 * control to fill the cell vertically.
	 * Not recommended. Use
	 * <code>new GridData(int, SWT.FILL, boolean, boolean)</code>
	 * instead
	 */
	public static final int VERTICAL_ALIGN_FILL = 1 << 4;

	/**
	 * Style bit for <code>new GridData(int)</code> to position the
	 * control at the left of the cell.
	 * Not recommended. Use
	 * <code>new GridData(SWT.BEGINNING, int, boolean, boolean)</code>
	 * instead.
	 */
	public static final int HORIZONTAL_ALIGN_BEGINNING =  1 << 5;

	/**
	 * Style bit for <code>new GridData(int)</code> to position the
	 * control in the horizontal center of the cell.
	 * Not recommended. Use
	 * <code>new GridData(SWT.CENTER, int, boolean, boolean)</code>
	 * instead.
	 */
	public static final int HORIZONTAL_ALIGN_CENTER = 1 << 6;

	/**
	 * Style bit for <code>new GridData(int)</code> to position the
	 * control at the right of the cell.
	 * Not recommended. Use
	 * <code>new GridData(SWT.END, int, boolean, boolean)</code>
	 * instead.
	 */
	public static final int HORIZONTAL_ALIGN_END = 1 << 7;

	/**
	 * Style bit for <code>new GridData(int)</code> to resize the
	 * control to fill the cell horizontally.
	 * Not recommended. Use
	 * <code>new GridData(SWT.FILL, int, boolean, boolean)</code>
	 * instead.
	 */
	public static final int HORIZONTAL_ALIGN_FILL = 1 << 8;

	/**
	 * Style bit for <code>new GridData(int)</code> to resize the
	 * control to fit the remaining horizontal space.
	 * Not recommended. Use
	 * <code>new GridData(int, int, true, boolean)</code>
	 * instead.
	 */
	public static final int GRAB_HORIZONTAL = 1 << 9;

	/**
	 * Style bit for <code>new GridData(int)</code> to resize the
	 * control to fit the remaining vertical space.
	 * Not recommended. Use
	 * <code>new GridData(int, int, boolean, true)</code>
	 * instead.
	 */
	public static final int GRAB_VERTICAL = 1 << 10;

	/**
	 * Style bit for <code>new GridData(int)</code> to resize the
	 * control to fill the cell vertically and to fit the remaining
	 * vertical space.
	 * FILL_VERTICAL = VERTICAL_ALIGN_FILL | GRAB_VERTICAL
	 * Not recommended. Use
	 * <code>new GridData(int, SWT.FILL, boolean, true)</code>
	 * instead.
	 */
	public static final int FILL_VERTICAL = VERTICAL_ALIGN_FILL | GRAB_VERTICAL;

	/**
	 * Style bit for <code>new GridData(int)</code> to resize the
	 * control to fill the cell horizontally and to fit the remaining
	 * horizontal space.
	 * FILL_HORIZONTAL = HORIZONTAL_ALIGN_FILL | GRAB_HORIZONTAL
	 * Not recommended. Use
	 * <code>new GridData(SWT.FILL, int, true, boolean)</code>
	 * instead.
	 */
	public static final int FILL_HORIZONTAL = HORIZONTAL_ALIGN_FILL | GRAB_HORIZONTAL;

	/**
	 * Style bit for <code>new GridData(int)</code> to resize the
	 * control to fill the cell horizontally and vertically and
	 * to fit the remaining horizontal and vertical space.
	 * FILL_BOTH = FILL_VERTICAL | FILL_HORIZONTAL
	 * Not recommended. Use
	 * <code>new GridData(SWT.FILL, SWT.FILL, true, true)</code>
	 * instead.
	 */
	public static final int FILL_BOTH = FILL_VERTICAL | FILL_HORIZONTAL;

	int cacheWidth = -1, cacheHeight = -1;
	int defaultWhint, defaultHhint, defaultWidth = -1, defaultHeight = -1;
	int currentWhint, currentHhint, currentWidth = -1, currentHeight = -1;

/**
 * Constructs a new instance of GridData using
 * default values.
 */
public GridData () {
	super ();
}

/**
 * Constructs a new instance based on the GridData style.
 * This constructor is not recommended.
 *
 * @param style the GridData style
 */
public GridData (int style) {
	super ();
	if ((style & VERTICAL_ALIGN_BEGINNING) != 0) verticalAlignment = BEGINNING;
	if ((style & VERTICAL_ALIGN_CENTER) != 0) verticalAlignment = CENTER;
	if ((style & VERTICAL_ALIGN_FILL) != 0) verticalAlignment = FILL;
	if ((style & VERTICAL_ALIGN_END) != 0) verticalAlignment = END;
	if ((style & HORIZONTAL_ALIGN_BEGINNING) != 0) horizontalAlignment = BEGINNING;
	if ((style & HORIZONTAL_ALIGN_CENTER) != 0) horizontalAlignment = CENTER;
	if ((style & HORIZONTAL_ALIGN_FILL) != 0) horizontalAlignment = FILL;
	if ((style & HORIZONTAL_ALIGN_END) != 0) horizontalAlignment = END;
	grabExcessHorizontalSpace = (style & GRAB_HORIZONTAL) != 0;
	grabExcessVerticalSpace = (style & GRAB_VERTICAL) != 0;
}

/**
 * Constructs a new instance of GridData according to the parameters.
 *
 * @param horizontalAlignment how control will be positioned horizontally within a cell,
 * 		one of: SWT.BEGINNING (or SWT.LEFT), SWT.CENTER, SWT.END (or SWT.RIGHT), or SWT.FILL
 * @param verticalAlignment how control will be positioned vertically within a cell,
 * 		one of: SWT.BEGINNING (or SWT.TOP), SWT.CENTER, SWT.END (or SWT.BOTTOM), or SWT.FILL
 * @param grabExcessHorizontalSpace whether cell will be made wide enough to fit the remaining horizontal space
 * @param grabExcessVerticalSpace whether cell will be made high enough to fit the remaining vertical space
 *
 * @since 3.0
 */
public GridData (int horizontalAlignment, int verticalAlignment, boolean grabExcessHorizontalSpace, boolean grabExcessVerticalSpace) {
	this (horizontalAlignment, verticalAlignment, grabExcessHorizontalSpace, grabExcessVerticalSpace, 1, 1);
}

/**
 * Constructs a new instance of GridData according to the parameters.
 *
 * @param horizontalAlignment how control will be positioned horizontally within a cell,
 * 		one of: SWT.BEGINNING (or SWT.LEFT), SWT.CENTER, SWT.END (or SWT.RIGHT), or SWT.FILL
 * @param verticalAlignment how control will be positioned vertically within a cell,
 * 		one of: SWT.BEGINNING (or SWT.TOP), SWT.CENTER, SWT.END (or SWT.BOTTOM), or SWT.FILL
 * @param grabExcessHorizontalSpace whether cell will be made wide enough to fit the remaining horizontal space
 * @param grabExcessVerticalSpace whether cell will be made high enough to fit the remaining vertical space
 * @param horizontalSpan the number of column cells that the control will take up
 * @param verticalSpan the number of row cells that the control will take up
 *
 * @since 3.0
 */
public GridData (int horizontalAlignment, int verticalAlignment, boolean grabExcessHorizontalSpace, boolean grabExcessVerticalSpace, int horizontalSpan, int verticalSpan) {
	super ();
	this.horizontalAlignment = horizontalAlignment;
	this.verticalAlignment = verticalAlignment;
	this.grabExcessHorizontalSpace = grabExcessHorizontalSpace;
	this.grabExcessVerticalSpace = grabExcessVerticalSpace;
	this.horizontalSpan = horizontalSpan;
	this.verticalSpan = verticalSpan;
}

/**
 * Constructs a new instance of GridData according to the parameters.
 * A value of SWT.DEFAULT indicates that no minimum width or
 * no minimum height is specified.
 *
 * @param width a minimum width for the column
 * @param height a minimum height for the row
 *
 * @since 3.0
 */
public GridData (int width, int height) {
	super ();
	this.widthHint = width;
	this.heightHint = height;
}

void computeSize (Control control, int wHint, int hHint, boolean flushCache) {
	if (cacheWidth != -1 && cacheHeight != -1) return;
	if (wHint == this.widthHint && hHint == this.heightHint) {
		if (defaultWidth == -1 || defaultHeight == -1 || wHint != defaultWhint || hHint != defaultHhint) {
			Point size = control.computeSize (wHint, hHint, flushCache);
			defaultWhint = wHint;
			defaultHhint = hHint;
			defaultWidth = size.x;
			defaultHeight = size.y;
		}
		cacheWidth = defaultWidth;
		cacheHeight = defaultHeight;
		return;
	}
	if (currentWidth == -1 || currentHeight == -1 || wHint != currentWhint || hHint != currentHhint) {
		Point size = control.computeSize (wHint, hHint, flushCache);
		currentWhint = wHint;
		currentHhint = hHint;
		currentWidth = size.x;
		currentHeight = size.y;
	}
	cacheWidth = currentWidth;
	cacheHeight = currentHeight;
}

void flushCache () {
	cacheWidth = cacheHeight = -1;
	defaultWidth = defaultHeight = -1;
	currentWidth = currentHeight = -1;
}

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

/**
 * Returns a string containing a concise, human-readable
 * description of the receiver.
 *
 * @return a string representation of the GridData object
 */
@Override
public String toString () {
	String hAlign = "";
	switch (horizontalAlignment) {
		case SWT.FILL: hAlign = "SWT.FILL"; break;
		case SWT.BEGINNING: hAlign = "SWT.BEGINNING"; break;
		case SWT.LEFT: hAlign = "SWT.LEFT"; break;
		case SWT.END: hAlign = "SWT.END"; break;
		case END: hAlign = "GridData.END"; break;
		case SWT.RIGHT: hAlign = "SWT.RIGHT"; break;
		case SWT.CENTER: hAlign = "SWT.CENTER"; break;
		case CENTER: hAlign = "GridData.CENTER"; break;
		default: hAlign = "Undefined "+horizontalAlignment; break;
	}
	String vAlign = "";
	switch (verticalAlignment) {
		case SWT.FILL: vAlign = "SWT.FILL"; break;
		case SWT.BEGINNING: vAlign = "SWT.BEGINNING"; break;
		case SWT.TOP: vAlign = "SWT.TOP"; break;
		case SWT.END: vAlign = "SWT.END"; break;
		case END: vAlign = "GridData.END"; break;
		case SWT.BOTTOM: vAlign = "SWT.BOTTOM"; break;
		case SWT.CENTER: vAlign = "SWT.CENTER"; break;
		case CENTER: vAlign = "GridData.CENTER"; break;
		default: vAlign = "Undefined "+verticalAlignment; break;
	}
 	String string = getName()+" {";
 	string += "horizontalAlignment="+hAlign+" ";
 	if (horizontalIndent != 0) string += "horizontalIndent="+horizontalIndent+" ";
 	if (horizontalSpan != 1) string += "horizontalSpan="+horizontalSpan+" ";
 	if (grabExcessHorizontalSpace) string += "grabExcessHorizontalSpace="+grabExcessHorizontalSpace+" ";
 	if (widthHint != SWT.DEFAULT) string += "widthHint="+widthHint+" ";
 	if (minimumWidth != 0) string += "minimumWidth="+minimumWidth+" ";
 	string += "verticalAlignment="+vAlign+" ";
 	if (verticalIndent != 0) string += "verticalIndent="+verticalIndent+" ";
	if (verticalSpan != 1) string += "verticalSpan="+verticalSpan+" ";
 	if (grabExcessVerticalSpace) string += "grabExcessVerticalSpace="+grabExcessVerticalSpace+" ";
 	if (heightHint != SWT.DEFAULT) string += "heightHint="+heightHint+" ";
 	if (minimumHeight != 0) string += "minimumHeight="+minimumHeight+" ";
 	if (exclude) string += "exclude="+exclude+" ";
 	string = string.trim();
 	string += "}";
	return string;
}
}