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src/java.desktop/share/classes/java/awt/GridLayout.java

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   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.awt;
  27 
  28 /**
  29  * The <code>GridLayout</code> class is a layout manager that
  30  * lays out a container's components in a rectangular grid.
  31  * The container is divided into equal-sized rectangles,
  32  * and one component is placed in each rectangle.
  33  * For example, the following is an applet that lays out six buttons
  34  * into three rows and two columns:
  35  *
  36  * <hr><blockquote>
  37  * <pre>
  38  * import java.awt.*;
  39  * import java.applet.Applet;
  40  * public class ButtonGrid extends Applet {
  41  *     public void init() {
  42  *         setLayout(new GridLayout(3,2));
  43  *         add(new Button("1"));
  44  *         add(new Button("2"));
  45  *         add(new Button("3"));
  46  *         add(new Button("4"));
  47  *         add(new Button("5"));
  48  *         add(new Button("6"));
  49  *     }
  50  * }
  51  * </pre></blockquote><hr>
  52  * <p>
  53  * If the container's <code>ComponentOrientation</code> property is horizontal
  54  * and left-to-right, the above example produces the output shown in Figure 1.
  55  * If the container's <code>ComponentOrientation</code> property is horizontal
  56  * and right-to-left, the example produces the output shown in Figure 2.
  57  *
  58  * <table style="float:center" WIDTH=600 summary="layout">
  59  * <tr ALIGN=CENTER>
  60  * <td><img SRC="doc-files/GridLayout-1.gif"
  61  *      alt="Shows 6 buttons in rows of 2. Row 1 shows buttons 1 then 2.
  62  * Row 2 shows buttons 3 then 4. Row 3 shows buttons 5 then 6.">
  63  * </td>
  64  *
  65  * <td ALIGN=CENTER><img SRC="doc-files/GridLayout-2.gif"
  66  *                   alt="Shows 6 buttons in rows of 2. Row 1 shows buttons 2 then 1.
  67  * Row 2 shows buttons 4 then 3. Row 3 shows buttons 6 then 5.">
  68  * </td>
  69  * </tr>
  70  *
  71  * <tr ALIGN=CENTER>
  72  * <td>Figure 1: Horizontal, Left-to-Right</td>
  73  *
  74  * <td>Figure 2: Horizontal, Right-to-Left</td>
  75  * </tr>
  76  * </table>
  77  * <p>
  78  * When both the number of rows and the number of columns have
  79  * been set to non-zero values, either by a constructor or
  80  * by the <tt>setRows</tt> and <tt>setColumns</tt> methods, the number of
  81  * columns specified is ignored.  Instead, the number of
  82  * columns is determined from the specified number of rows
  83  * and the total number of components in the layout. So, for
  84  * example, if three rows and two columns have been specified
  85  * and nine components are added to the layout, they will
  86  * be displayed as three rows of three columns.  Specifying
  87  * the number of columns affects the layout only when the
  88  * number of rows is set to zero.
  89  *
  90  * @author  Arthur van Hoff
  91  * @since   1.0
  92  */
  93 public class GridLayout implements LayoutManager, java.io.Serializable {
  94     /*
  95      * serialVersionUID
  96      */
  97     private static final long serialVersionUID = -7411804673224730901L;
  98 
  99     /**
 100      * This is the horizontal gap (in pixels) which specifies the space


 137      *
 138      * @serial
 139      * @see #getColumns()
 140      * @see #setColumns(int)
 141      */
 142     int cols;
 143 
 144     /**
 145      * Creates a grid layout with a default of one column per component,
 146      * in a single row.
 147      * @since 1.1
 148      */
 149     public GridLayout() {
 150         this(1, 0, 0, 0);
 151     }
 152 
 153     /**
 154      * Creates a grid layout with the specified number of rows and
 155      * columns. All components in the layout are given equal size.
 156      * <p>
 157      * One, but not both, of <code>rows</code> and <code>cols</code> can
 158      * be zero, which means that any number of objects can be placed in a
 159      * row or in a column.
 160      * @param     rows   the rows, with the value zero meaning
 161      *                   any number of rows.
 162      * @param     cols   the columns, with the value zero meaning
 163      *                   any number of columns.
 164      */
 165     public GridLayout(int rows, int cols) {
 166         this(rows, cols, 0, 0);
 167     }
 168 
 169     /**
 170      * Creates a grid layout with the specified number of rows and
 171      * columns. All components in the layout are given equal size.
 172      * <p>
 173      * In addition, the horizontal and vertical gaps are set to the
 174      * specified values. Horizontal gaps are placed between each
 175      * of the columns. Vertical gaps are placed between each of
 176      * the rows.
 177      * <p>
 178      * One, but not both, of <code>rows</code> and <code>cols</code> can
 179      * be zero, which means that any number of objects can be placed in a
 180      * row or in a column.
 181      * <p>
 182      * All <code>GridLayout</code> constructors defer to this one.
 183      * @param     rows   the rows, with the value zero meaning
 184      *                   any number of rows
 185      * @param     cols   the columns, with the value zero meaning
 186      *                   any number of columns
 187      * @param     hgap   the horizontal gap
 188      * @param     vgap   the vertical gap
 189      * @exception   IllegalArgumentException  if the value of both
 190      *                  <code>rows</code> and <code>cols</code> is
 191      *                  set to zero
 192      */
 193     public GridLayout(int rows, int cols, int hgap, int vgap) {
 194         if ((rows == 0) && (cols == 0)) {
 195             throw new IllegalArgumentException("rows and cols cannot both be zero");
 196         }
 197         this.rows = rows;
 198         this.cols = cols;
 199         this.hgap = hgap;
 200         this.vgap = vgap;
 201     }
 202 
 203     /**
 204      * Gets the number of rows in this layout.
 205      * @return    the number of rows in this layout
 206      * @since     1.1
 207      */
 208     public int getRows() {
 209         return rows;
 210     }
 211 
 212     /**
 213      * Sets the number of rows in this layout to the specified value.
 214      * @param        rows   the number of rows in this layout
 215      * @exception    IllegalArgumentException  if the value of both
 216      *               <code>rows</code> and <code>cols</code> is set to zero
 217      * @since        1.1
 218      */
 219     public void setRows(int rows) {
 220         if ((rows == 0) && (this.cols == 0)) {
 221             throw new IllegalArgumentException("rows and cols cannot both be zero");
 222         }
 223         this.rows = rows;
 224     }
 225 
 226     /**
 227      * Gets the number of columns in this layout.
 228      * @return     the number of columns in this layout
 229      * @since      1.1
 230      */
 231     public int getColumns() {
 232         return cols;
 233     }
 234 
 235     /**
 236      * Sets the number of columns in this layout to the specified value.
 237      * Setting the number of columns has no affect on the layout
 238      * if the number of rows specified by a constructor or by
 239      * the <tt>setRows</tt> method is non-zero. In that case, the number
 240      * of columns displayed in the layout is determined by the total
 241      * number of components and the number of rows specified.
 242      * @param        cols   the number of columns in this layout
 243      * @exception    IllegalArgumentException  if the value of both
 244      *               <code>rows</code> and <code>cols</code> is set to zero
 245      * @since        1.1
 246      */
 247     public void setColumns(int cols) {
 248         if ((cols == 0) && (this.rows == 0)) {
 249             throw new IllegalArgumentException("rows and cols cannot both be zero");
 250         }
 251         this.cols = cols;
 252     }
 253 
 254     /**
 255      * Gets the horizontal gap between components.
 256      * @return       the horizontal gap between components
 257      * @since        1.1
 258      */
 259     public int getHgap() {
 260         return hgap;
 261     }
 262 
 263     /**
 264      * Sets the horizontal gap between components to the specified value.


 388         for (int i = 0 ; i < ncomponents ; i++) {
 389             Component comp = parent.getComponent(i);
 390             Dimension d = comp.getMinimumSize();
 391             if (w < d.width) {
 392                 w = d.width;
 393             }
 394             if (h < d.height) {
 395                 h = d.height;
 396             }
 397         }
 398         return new Dimension(insets.left + insets.right + ncols*w + (ncols-1)*hgap,
 399                              insets.top + insets.bottom + nrows*h + (nrows-1)*vgap);
 400       }
 401     }
 402 
 403     /**
 404      * Lays out the specified container using this layout.
 405      * <p>
 406      * This method reshapes the components in the specified target
 407      * container in order to satisfy the constraints of the
 408      * <code>GridLayout</code> object.
 409      * <p>
 410      * The grid layout manager determines the size of individual
 411      * components by dividing the free space in the container into
 412      * equal-sized portions according to the number of rows and columns
 413      * in the layout. The container's free space equals the container's
 414      * size minus any insets and any specified horizontal or vertical
 415      * gap. All components in a grid layout are given the same size.
 416      *
 417      * @param      parent   the container in which to do the layout
 418      * @see        java.awt.Container
 419      * @see        java.awt.Container#doLayout
 420      */
 421     public void layoutContainer(Container parent) {
 422       synchronized (parent.getTreeLock()) {
 423         Insets insets = parent.getInsets();
 424         int ncomponents = parent.getComponentCount();
 425         int nrows = rows;
 426         int ncols = cols;
 427         boolean ltr = parent.getComponentOrientation().isLeftToRight();
 428 




   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.awt;
  27 
  28 /**
  29  * The {@code GridLayout} class is a layout manager that
  30  * lays out a container's components in a rectangular grid.
  31  * The container is divided into equal-sized rectangles,
  32  * and one component is placed in each rectangle.
  33  * For example, the following is an applet that lays out six buttons
  34  * into three rows and two columns:
  35  *
  36  * <hr><blockquote>
  37  * <pre>
  38  * import java.awt.*;
  39  * import java.applet.Applet;
  40  * public class ButtonGrid extends Applet {
  41  *     public void init() {
  42  *         setLayout(new GridLayout(3,2));
  43  *         add(new Button("1"));
  44  *         add(new Button("2"));
  45  *         add(new Button("3"));
  46  *         add(new Button("4"));
  47  *         add(new Button("5"));
  48  *         add(new Button("6"));
  49  *     }
  50  * }
  51  * </pre></blockquote><hr>
  52  * <p>
  53  * If the container's {@code ComponentOrientation} property is horizontal
  54  * and left-to-right, the above example produces the output shown in Figure 1.
  55  * If the container's {@code ComponentOrientation} property is horizontal
  56  * and right-to-left, the example produces the output shown in Figure 2.
  57  *
  58  * <table style="float:center" WIDTH=600 summary="layout">
  59  * <tr ALIGN=CENTER>
  60  * <td><img SRC="doc-files/GridLayout-1.gif"
  61  *      alt="Shows 6 buttons in rows of 2. Row 1 shows buttons 1 then 2.
  62  * Row 2 shows buttons 3 then 4. Row 3 shows buttons 5 then 6.">
  63  * </td>
  64  *
  65  * <td ALIGN=CENTER><img SRC="doc-files/GridLayout-2.gif"
  66  *                   alt="Shows 6 buttons in rows of 2. Row 1 shows buttons 2 then 1.
  67  * Row 2 shows buttons 4 then 3. Row 3 shows buttons 6 then 5.">
  68  * </td>
  69  * </tr>
  70  *
  71  * <tr ALIGN=CENTER>
  72  * <td>Figure 1: Horizontal, Left-to-Right</td>
  73  *
  74  * <td>Figure 2: Horizontal, Right-to-Left</td>
  75  * </tr>
  76  * </table>
  77  * <p>
  78  * When both the number of rows and the number of columns have
  79  * been set to non-zero values, either by a constructor or
  80  * by the {@code setRows} and {@code setColumns} methods, the number of
  81  * columns specified is ignored.  Instead, the number of
  82  * columns is determined from the specified number of rows
  83  * and the total number of components in the layout. So, for
  84  * example, if three rows and two columns have been specified
  85  * and nine components are added to the layout, they will
  86  * be displayed as three rows of three columns.  Specifying
  87  * the number of columns affects the layout only when the
  88  * number of rows is set to zero.
  89  *
  90  * @author  Arthur van Hoff
  91  * @since   1.0
  92  */
  93 public class GridLayout implements LayoutManager, java.io.Serializable {
  94     /*
  95      * serialVersionUID
  96      */
  97     private static final long serialVersionUID = -7411804673224730901L;
  98 
  99     /**
 100      * This is the horizontal gap (in pixels) which specifies the space


 137      *
 138      * @serial
 139      * @see #getColumns()
 140      * @see #setColumns(int)
 141      */
 142     int cols;
 143 
 144     /**
 145      * Creates a grid layout with a default of one column per component,
 146      * in a single row.
 147      * @since 1.1
 148      */
 149     public GridLayout() {
 150         this(1, 0, 0, 0);
 151     }
 152 
 153     /**
 154      * Creates a grid layout with the specified number of rows and
 155      * columns. All components in the layout are given equal size.
 156      * <p>
 157      * One, but not both, of {@code rows} and {@code cols} can
 158      * be zero, which means that any number of objects can be placed in a
 159      * row or in a column.
 160      * @param     rows   the rows, with the value zero meaning
 161      *                   any number of rows.
 162      * @param     cols   the columns, with the value zero meaning
 163      *                   any number of columns.
 164      */
 165     public GridLayout(int rows, int cols) {
 166         this(rows, cols, 0, 0);
 167     }
 168 
 169     /**
 170      * Creates a grid layout with the specified number of rows and
 171      * columns. All components in the layout are given equal size.
 172      * <p>
 173      * In addition, the horizontal and vertical gaps are set to the
 174      * specified values. Horizontal gaps are placed between each
 175      * of the columns. Vertical gaps are placed between each of
 176      * the rows.
 177      * <p>
 178      * One, but not both, of {@code rows} and {@code cols} can
 179      * be zero, which means that any number of objects can be placed in a
 180      * row or in a column.
 181      * <p>
 182      * All {@code GridLayout} constructors defer to this one.
 183      * @param     rows   the rows, with the value zero meaning
 184      *                   any number of rows
 185      * @param     cols   the columns, with the value zero meaning
 186      *                   any number of columns
 187      * @param     hgap   the horizontal gap
 188      * @param     vgap   the vertical gap
 189      * @exception   IllegalArgumentException  if the value of both
 190      *                  {@code rows} and {@code cols} is
 191      *                  set to zero
 192      */
 193     public GridLayout(int rows, int cols, int hgap, int vgap) {
 194         if ((rows == 0) && (cols == 0)) {
 195             throw new IllegalArgumentException("rows and cols cannot both be zero");
 196         }
 197         this.rows = rows;
 198         this.cols = cols;
 199         this.hgap = hgap;
 200         this.vgap = vgap;
 201     }
 202 
 203     /**
 204      * Gets the number of rows in this layout.
 205      * @return    the number of rows in this layout
 206      * @since     1.1
 207      */
 208     public int getRows() {
 209         return rows;
 210     }
 211 
 212     /**
 213      * Sets the number of rows in this layout to the specified value.
 214      * @param        rows   the number of rows in this layout
 215      * @exception    IllegalArgumentException  if the value of both
 216      *               {@code rows} and {@code cols} is set to zero
 217      * @since        1.1
 218      */
 219     public void setRows(int rows) {
 220         if ((rows == 0) && (this.cols == 0)) {
 221             throw new IllegalArgumentException("rows and cols cannot both be zero");
 222         }
 223         this.rows = rows;
 224     }
 225 
 226     /**
 227      * Gets the number of columns in this layout.
 228      * @return     the number of columns in this layout
 229      * @since      1.1
 230      */
 231     public int getColumns() {
 232         return cols;
 233     }
 234 
 235     /**
 236      * Sets the number of columns in this layout to the specified value.
 237      * Setting the number of columns has no affect on the layout
 238      * if the number of rows specified by a constructor or by
 239      * the {@code setRows} method is non-zero. In that case, the number
 240      * of columns displayed in the layout is determined by the total
 241      * number of components and the number of rows specified.
 242      * @param        cols   the number of columns in this layout
 243      * @exception    IllegalArgumentException  if the value of both
 244      *               {@code rows} and {@code cols} is set to zero
 245      * @since        1.1
 246      */
 247     public void setColumns(int cols) {
 248         if ((cols == 0) && (this.rows == 0)) {
 249             throw new IllegalArgumentException("rows and cols cannot both be zero");
 250         }
 251         this.cols = cols;
 252     }
 253 
 254     /**
 255      * Gets the horizontal gap between components.
 256      * @return       the horizontal gap between components
 257      * @since        1.1
 258      */
 259     public int getHgap() {
 260         return hgap;
 261     }
 262 
 263     /**
 264      * Sets the horizontal gap between components to the specified value.


 388         for (int i = 0 ; i < ncomponents ; i++) {
 389             Component comp = parent.getComponent(i);
 390             Dimension d = comp.getMinimumSize();
 391             if (w < d.width) {
 392                 w = d.width;
 393             }
 394             if (h < d.height) {
 395                 h = d.height;
 396             }
 397         }
 398         return new Dimension(insets.left + insets.right + ncols*w + (ncols-1)*hgap,
 399                              insets.top + insets.bottom + nrows*h + (nrows-1)*vgap);
 400       }
 401     }
 402 
 403     /**
 404      * Lays out the specified container using this layout.
 405      * <p>
 406      * This method reshapes the components in the specified target
 407      * container in order to satisfy the constraints of the
 408      * {@code GridLayout} object.
 409      * <p>
 410      * The grid layout manager determines the size of individual
 411      * components by dividing the free space in the container into
 412      * equal-sized portions according to the number of rows and columns
 413      * in the layout. The container's free space equals the container's
 414      * size minus any insets and any specified horizontal or vertical
 415      * gap. All components in a grid layout are given the same size.
 416      *
 417      * @param      parent   the container in which to do the layout
 418      * @see        java.awt.Container
 419      * @see        java.awt.Container#doLayout
 420      */
 421     public void layoutContainer(Container parent) {
 422       synchronized (parent.getTreeLock()) {
 423         Insets insets = parent.getInsets();
 424         int ncomponents = parent.getComponentCount();
 425         int nrows = rows;
 426         int ncols = cols;
 427         boolean ltr = parent.getComponentOrientation().isLeftToRight();
 428 


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