Apple Developer Connection Student Program/ADC Tools Sampler CD Disk 3 1999.iso/Metrowerks CodeWarrior/Java Support/Java_Source/Java2/src/java/awt/GridLayout.java

Java Source | 1999-05-28 | 13.1 KB | 407 lines | [TEXT/CWIE]

/*
 * @(#)GridLayout.java    1.23 98/09/21
 *
 * Copyright 1995-1998 by Sun Microsystems, Inc.,
 * 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
 * All rights reserved.
 *
 * This software is the confidential and proprietary information
 * of Sun Microsystems, Inc. ("Confidential Information").  You
 * shall not disclose such Confidential Information and shall use
 * it only in accordance with the terms of the license agreement
 * you entered into with Sun.
 */

package java.awt;

/**
 * The <code>GridLayout</code> class is a layout manager that
 * lays out a container's components in a rectangular grid.
 * <p>
 * The container is divided into equal-sized rectangles,
 * and one component is placed in each rectangle.
 * <p>
 * For example, the following is an applet that lays out six buttons
 * into three rows and two columns:
 * <p>
 * <hr><blockquote><pre>
 * import java.awt.*;
 * import java.applet.Applet;
 * public class ButtonGrid extends Applet {
 *     public void init() {
 *         setLayout(new GridLayout(3,2));
 *         add(new Button("1"));
 *         add(new Button("2"));
 *         add(new Button("3"));
 *         add(new Button("4"));
 *         add(new Button("5"));
 *         add(new Button("6"));
 *     }
 * }
 * </pre></blockquote><hr>
 * <p>
 * It produces the following output:
 * <p>
 * <img src="doc-files/GridLayout-1.gif"
 * ALIGN=center HSPACE=10 VSPACE=7>
 *
 * @version 1.23, 09/21/98
 * @author
 * @since   JDK1.0
 */
public class GridLayout implements LayoutManager, java.io.Serializable {
    /**
     * This is the horizontal gap (in pixels) which specifies the space
     * between columns.  They can be changed at any time.
     * This should be a non negative integer.
     *
     * @serial
     * @see getHgap()
     * @see setHgap()
     */
    int hgap;
    /**
     * This is the vertical gap (in pixels) which specifies the space
     * between rows.  They can be changed at any time.
     * This should be a non negative integer.
     *
     * @serial
     * @see getVgap()
     * @see setVgap()
     */
    int vgap;
    /**
     * This is the number of rows specified for the grid.  The number
     * of rows can be changed at any time.
     * This should be a non negative integer, where '0' means
     * 'any number' meaning that the number of Rows in that
     * dimension depends on the other dimension.
     *
     * @serial
     * @see getRows()
     * @see setRows()
     */
    int rows;
    /**
     * This is the number of columns specified for the grid.  The number
     * of columns can be changed at any time.
     * This should be a non negative integer, where '0' means
     * 'any number' meaning that the number of Columns in that
     * dimension depends on the other dimension.
     *
     * @serial
     * @see getColumns()
     * @see setColumns()
     */
    int cols;

    /**
     * Creates a grid layout with a default of one column per component,
     * in a single row.
     * @since JDK1.1
     */
    public GridLayout() {
    this(1, 0, 0, 0);
    }

    /**
     * Creates a grid layout with the specified number of rows and
     * columns. All components in the layout are given equal size.
     * <p>
     * One, but not both, of <code>rows</code> and <code>cols</code> can
     * be zero, which means that any number of objects can be placed in a
     * row or in a column.
     * @param     rows   the rows, with the value zero meaning
     *                   any number of rows.
     * @param     cols   the columns, with the value zero meaning
     *                   any number of columns.
     */
    public GridLayout(int rows, int cols) {
    this(rows, cols, 0, 0);
    }

    /**
     * Creates a grid layout with the specified number of rows and
     * columns. All components in the layout are given equal size.
     * <p>
     * In addition, the horizontal and vertical gaps are set to the
     * specified values. Horizontal gaps are placed at the left and
     * right edges, and between each of the columns. Vertical gaps are
     * placed at the top and bottom edges, and between each of the rows.
     * <p>
     * One, but not both, of <code>rows</code> and <code>cols</code> can
     * be zero, which means that any number of objects can be placed in a
     * row or in a column.
     * @param     rows   the rows, with the value zero meaning
     *                   any number of rows.
     * @param     cols   the columns, with the value zero meaning
     *                   any number of columns.
     * @param     hgap   the horizontal gap.
     * @param     vgap   the vertical gap.
     * @exception   IllegalArgumentException  if the of <code>rows</code>
     *                   or <code>cols</code> is invalid.
     */
    public GridLayout(int rows, int cols, int hgap, int vgap) {
    if ((rows == 0) && (cols == 0)) {
        throw new IllegalArgumentException("rows and cols cannot both be zero");
    }
    this.rows = rows;
    this.cols = cols;
    this.hgap = hgap;
    this.vgap = vgap;
    }

    /**
     * Gets the number of rows in this layout.
     * @return    the number of rows in this layout.
     * @since     JDK1.1
     */
    public int getRows() {
    return rows;
    }

    /**
     * Sets the number of rows in this layout to the specified value.
     * @param        rows   the number of rows in this layout.
     * @exception    IllegalArgumentException  if the value of both
     *               <code>rows</code> and <code>cols</code> is set to zero.
     * @since        JDK1.1
     */
    public void setRows(int rows) {
    if ((rows == 0) && (this.cols == 0)) {
        throw new IllegalArgumentException("rows and cols cannot both be zero");
    }
    this.rows = rows;
    }

    /**
     * Gets the number of columns in this layout.
     * @return     the number of columns in this layout.
     * @since      JDK1.1
     */
    public int getColumns() {
    return cols;
    }

    /**
     * Sets the number of columns in this layout to the specified value.
     * @param        cols   the number of columns in this layout.
     * @exception    IllegalArgumentException  if the value of both
     *               <code>rows</code> and <code>cols</code> is set to zero.
     * @since        JDK1.1
     */
    public void setColumns(int cols) {
    if ((cols == 0) && (this.rows == 0)) {
        throw new IllegalArgumentException("rows and cols cannot both be zero");
    }
    this.cols = cols;
    }

    /**
     * Gets the horizontal gap between components.
     * @return       the horizontal gap between components.
     * @since        JDK1.1
     */
    public int getHgap() {
    return hgap;
    }

    /**
     * Sets the horizontal gap between components to the specified value.
     * @param        hgap   the horizontal gap between components.
     * @since        JDK1.1
     */
    public void setHgap(int hgap) {
    this.hgap = hgap;
    }

    /**
     * Gets the vertical gap between components.
     * @return       the vertical gap between components.
     * @since        JDK1.1
     */
    public int getVgap() {
    return vgap;
    }

    /**
     * Sets the vertical gap between components to the specified value.
     * @param         vgap  the vertical gap between components.
     * @since        JDK1.1
     */
    public void setVgap(int vgap) {
    this.vgap = vgap;
    }

    /**
     * Adds the specified component with the specified name to the layout.
     * @param name the name of the component.
     * @param comp the component to be added.
     */
    public void addLayoutComponent(String name, Component comp) {
    }

    /**
     * Removes the specified component from the layout.
     * @param comp the component to be removed.
     */
    public void removeLayoutComponent(Component comp) {
    }

    /**
     * Determines the preferred size of the container argument using
     * this grid layout.
     * <p>
     * The preferred width of a grid layout is the largest preferred
     * width of any of the widths in the container times the number of
     * columns, plus the horizontal padding times the number of columns
     * plus one, plus the left and right insets of the target container.
     * <p>
     * The preferred height of a grid layout is the largest preferred
     * height of any of the heights in the container times the number of
     * rows, plus the vertical padding times the number of rows plus one,
     * plus the top and bottom insets of the target container.
     *
     * @param     target   the container in which to do the layout.
     * @return    the preferred dimensions to lay out the
     *                      subcomponents of the specified container.
     * @see       java.awt.GridLayout#minimumLayoutSize
     * @see       java.awt.Container#getPreferredSize()
     */
    public Dimension preferredLayoutSize(Container parent) {
      synchronized (parent.getTreeLock()) {
    Insets insets = parent.getInsets();
    int ncomponents = parent.getComponentCount();
    int nrows = rows;
    int ncols = cols;

    if (nrows > 0) {
        ncols = (ncomponents + nrows - 1) / nrows;
    } else {
        nrows = (ncomponents + ncols - 1) / ncols;
    }
    int w = 0;
    int h = 0;
    for (int i = 0 ; i < ncomponents ; i++) {
        Component comp = parent.getComponent(i);
        Dimension d = comp.getPreferredSize();
        if (w < d.width) {
        w = d.width;
        }
        if (h < d.height) {
        h = d.height;
        }
    }
    return new Dimension(insets.left + insets.right + ncols*w + (ncols-1)*hgap,
                 insets.top + insets.bottom + nrows*h + (nrows-1)*vgap);
      }
    }

    /**
     * Determines the minimum size of the container argument using this
     * grid layout.
     * <p>
     * The minimum width of a grid layout is the largest minimum width
     * of any of the widths in the container times the number of columns,
     * plus the horizontal padding times the number of columns plus one,
     * plus the left and right insets of the target container.
     * <p>
     * The minimum height of a grid layout is the largest minimum height
     * of any of the heights in the container times the number of rows,
     * plus the vertical padding times the number of rows plus one, plus
     * the top and bottom insets of the target container.
     *
     * @param       target   the container in which to do the layout.
     * @return      the minimum dimensions needed to lay out the
     *                      subcomponents of the specified container.
     * @see         java.awt.GridLayout#preferredLayoutSize
     * @see         java.awt.Container#doLayout
     */
    public Dimension minimumLayoutSize(Container parent) {
      synchronized (parent.getTreeLock()) {
        Insets insets = parent.getInsets();
    int ncomponents = parent.getComponentCount();
    int nrows = rows;
    int ncols = cols;

    if (nrows > 0) {
        ncols = (ncomponents + nrows - 1) / nrows;
    } else {
        nrows = (ncomponents + ncols - 1) / ncols;
    }
    int w = 0;
    int h = 0;
    for (int i = 0 ; i < ncomponents ; i++) {
        Component comp = parent.getComponent(i);
        Dimension d = comp.getMinimumSize();
        if (w < d.width) {
        w = d.width;
        }
        if (h < d.height) {
        h = d.height;
        }
    }
    return new Dimension(insets.left + insets.right + ncols*w + (ncols-1)*hgap,
                 insets.top + insets.bottom + nrows*h + (nrows-1)*vgap);
      }
    }

    /**
     * Lays out the specified container using this layout.
     * <p>
     * This method reshapes the components in the specified target
     * container in order to satisfy the constraints of the
     * <code>GridLayout</code> object.
     * <p>
     * The grid layout manager determines the size of individual
     * components by dividing the free space in the container into
     * equal-sized portions according to the number of rows and columns
     * in the layout. The container's free space equals the container's
     * size minus any insets and any specified horizontal or vertical
     * gap. All components in a grid layout are given the same size.
     *
     * @param      target   the container in which to do the layout.
     * @see        java.awt.Container
     * @see        java.awt.Container#doLayout
     */
    public void layoutContainer(Container parent) {
      synchronized (parent.getTreeLock()) {
    Insets insets = parent.getInsets();
    int ncomponents = parent.getComponentCount();
    int nrows = rows;
    int ncols = cols;

    if (ncomponents == 0) {
        return;
    }
    if (nrows > 0) {
        ncols = (ncomponents + nrows - 1) / nrows;
    } else {
        nrows = (ncomponents + ncols - 1) / ncols;
    }
    int w = parent.width - (insets.left + insets.right);
    int h = parent.height - (insets.top + insets.bottom);
    w = (w - (ncols - 1) * hgap) / ncols;
    h = (h - (nrows - 1) * vgap) / nrows;

    for (int c = 0, x = insets.left ; c < ncols ; c++, x += w + hgap) {
        for (int r = 0, y = insets.top ; r < nrows ; r++, y += h + vgap) {
        int i = r * ncols + c;
        if (i < ncomponents) {
            parent.getComponent(i).setBounds(x, y, w, h);
        }
        }
    }
      }
    }

    /**
     * Returns the string representation of this grid layout's values.
     * @return     a string representation of this grid layout.
     */
    public String toString() {
    return getClass().getName() + "[hgap=" + hgap + ",vgap=" + vgap +
                           ",rows=" + rows + ",cols=" + cols + "]";
    }
}