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package java.awt;
/**
* The {@code GridLayout} 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:
*
* <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} property is horizontal
* and left-to-right, the above example produces the output shown in Figure 1.
* If the container's {@code ComponentOrientation} property is horizontal
* and right-to-left, the example produces the output shown in Figure 2.
*
* <div style="margin:0 auto;width:600px;text-align:center;font-weight:bold">
* <div style="float:left">
* <p><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.">
* <p>Figure 1: Horizontal, Left-to-Right
* </div>
* <div style="float:right">
* <p><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.">
* <p>Figure 2: Horizontal, Right-to-Left
* </div>
* <br style="clear:both;">
* </div>
* <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 {@code setRows} and {@code setColumns} 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 1.0
*/
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 1.1
*/
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} and {@code cols} 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} and {@code cols} can
* be zero, which means that any number of objects can be placed in a
* row or in a column.
* <p>
* All {@code GridLayout} 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} and {@code cols} 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 1.1
*/
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} and {@code cols} is set to zero
* @since 1.1
*/
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 1.1
*/
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 {@code setRows} 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} and {@code cols} is set to zero
* @since 1.1
*/
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 1.1
*/
public int getHgap() {
return hgap;
}
/**
* Sets the horizontal gap between components to the specified value.
* @param hgap the horizontal gap between components
* @since 1.1
*/
public void setHgap(int hgap) {
this.hgap = hgap;
}
/**
* Gets the vertical gap between components.
* @return the vertical gap between components
* @since 1.1
*/
public int getVgap() {
return vgap;
}
/**
* Sets the vertical gap between components to the specified value.
* @param vgap the vertical gap between components
* @since 1.1
*/
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} 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);
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