/* * Copyright (c) 1995, 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.awt; /** * The <code>GridLayout</code> class is a layout manager that * lays out a container's components in a rectangular grid. * The container is divided into equal-sized rectangles, * and one component is placed in each rectangle. * 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> * If the container's <code>ComponentOrientation</code> property is horizontal * and left-to-right, the above example produces the output shown in Figure 1. * If the container's <code>ComponentOrientation</code> property is horizontal * and right-to-left, the example produces the output shown in Figure 2. * <p> * <center><table COLS=2 WIDTH=600 summary="layout"> * <tr ALIGN=CENTER> * <td><img SRC="doc-files/GridLayout-1.gif" *      alt="Shows 6 buttons in rows of 2. Row 1 shows buttons 1 then 2. * Row 2 shows buttons 3 then 4. Row 3 shows buttons 5 then 6."> * </td> * * <td ALIGN=CENTER><img SRC="doc-files/GridLayout-2.gif" *                   alt="Shows 6 buttons in rows of 2. Row 1 shows buttons 2 then 1. * Row 2 shows buttons 4 then 3. Row 3 shows buttons 6 then 5."> * </td> * </tr> * * <tr ALIGN=CENTER> * <td>Figure 1: Horizontal, Left-to-Right</td> * * <td>Figure 2: Horizontal, Right-to-Left</td> * </tr> * </table></center> * <p> * When both the number of rows and the number of columns have * been set to non-zero values, either by a constructor or * by the <tt>setRows</tt> and <tt>setColumns</tt> methods, the number of * columns specified is ignored.  Instead, the number of * columns is determined from the specified number of rows * and the total number of components in the layout. So, for * example, if three rows and two columns have been specified * and nine components are added to the layout, they will * be displayed as three rows of three columns.  Specifying * the number of columns affects the layout only when the * number of rows is set to zero. * * @author  Arthur van Hoff * @since   JDK1.0 */public class GridLayout implements LayoutManager, java.io.Serializable {    /*     * serialVersionUID     */    private static final long serialVersionUID = -7411804673224730901L;     /**     * 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)     */    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)     */    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)     */    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)     */    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 between each     * of the columns. Vertical gaps are placed 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.     * <p>     * All <code>GridLayout</code> constructors defer to this one.     * @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 value of both     *                  <code>rows</code> and <code>cols</code> is     *                  set to zero     */    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.     * Setting the number of columns has no affect on the layout     * if the number of rows specified by a constructor or by     * the <tt>setRows</tt> method is non-zero. In that case, the number     * of columns displayed in the layout is determined by the total     * number of components and the number of rows specified.     * @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 all of the components in the container times the number of     * columns, plus the horizontal padding times the number of columns     * minus 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 all of the components in the container times the number of     * rows, plus the vertical padding times the number of rows minus one,     * plus the top and bottom insets of the target container.     *     * @param     parent   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 all of the components in the container times the number of columns,     * plus the horizontal padding times the number of columns minus 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 all of the components in the container times the number of rows,     * plus the vertical padding times the number of rows minus one, plus     * the top and bottom insets of the target container.     *     * @param       parent   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      parent   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;        boolean ltr = parent.getComponentOrientation().isLeftToRight();         if (ncomponents == 0) {            return;        }        if (nrows > 0) {            ncols = (ncomponents + nrows - 1) / nrows;        } else {            nrows = (ncomponents + ncols - 1) / ncols;        }        // 4370316. To position components in the center we should:        // 1. get an amount of extra space within Container        // 2. incorporate half of that value to the left/top position        // Note that we use trancating division for widthOnComponent        // The reminder goes to extraWidthAvailable        int totalGapsWidth = (ncols - 1) * hgap;        int widthWOInsets = parent.width - (insets.left + insets.right);        int widthOnComponent = (widthWOInsets - totalGapsWidth) / ncols;        int extraWidthAvailable = (widthWOInsets - (widthOnComponent * ncols + totalGapsWidth)) / 2;         int totalGapsHeight = (nrows - 1) * vgap;        int heightWOInsets = parent.height - (insets.top + insets.bottom);        int heightOnComponent = (heightWOInsets - totalGapsHeight) / nrows;        int extraHeightAvailable = (heightWOInsets - (heightOnComponent * nrows + totalGapsHeight)) / 2;        if (ltr) {            for (int c = 0, x = insets.left + extraWidthAvailable; c < ncols ; c++, x += widthOnComponent + hgap) {                for (int r = 0, y = insets.top + extraHeightAvailable; r < nrows ; r++, y += heightOnComponent + vgap) {                    int i = r * ncols + c;                    if (i < ncomponents) {                        parent.getComponent(i).setBounds(x, y, widthOnComponent, heightOnComponent);                    }                }            }        } else {            for (int c = 0, x = (parent.width - insets.right - widthOnComponent) - extraWidthAvailable; c < ncols ; c++, x -= widthOnComponent + hgap) {                for (int r = 0, y = insets.top + extraHeightAvailable; r < nrows ; r++, y += heightOnComponent + vgap) {                    int i = r * ncols + c;                    if (i < ncomponents) {                        parent.getComponent(i).setBounds(x, y, widthOnComponent, heightOnComponent);                    }                }            }        }      }    }     /**     * 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 + "]";    }}