Mega Code Archive
Utility methods for creating form- or grid-style layouts with SpringLayout
<![CDATA[
//package modrcon;
import javax.swing.*;
import javax.swing.SpringLayout;
import java.awt.*;
/**
* A 1.4 file that provides utility methods for
* creating form- or grid-style layouts with SpringLayout.
* These utilities are used by several programs, such as
* SpringBox and SpringCompactGrid.
*/
public class SpringUtilities {
/**
* A debugging utility that prints to stdout the component's
* minimum, preferred, and maximum sizes.
*/
public static void printSizes(Component c) {
System.out.println("minimumSize = " + c.getMinimumSize());
System.out.println("preferredSize = " + c.getPreferredSize());
System.out.println("maximumSize = " + c.getMaximumSize());
}
/**
* Aligns the first <code>rows</code> * <code>cols</code>
* components of <code>parent</code> in
* a grid. Each component is as big as the maximum
* preferred width and height of the components.
* The parent is made just big enough to fit them all.
*
* @param rows number of rows
* @param cols number of columns
* @param initialX x location to start the grid at
* @param initialY y location to start the grid at
* @param xPad x padding between cells
* @param yPad y padding between cells
*/
public static void makeGrid(Container parent,
int rows, int cols,
int initialX, int initialY,
int xPad, int yPad) {
SpringLayout layout;
try {
layout = (SpringLayout)parent.getLayout();
} catch (ClassCastException exc) {
System.err.println("The first argument to makeGrid must use SpringLayout.");
return;
}
Spring xPadSpring = Spring.constant(xPad);
Spring yPadSpring = Spring.constant(yPad);
Spring initialXSpring = Spring.constant(initialX);
Spring initialYSpring = Spring.constant(initialY);
int max = rows * cols;
//Calculate Springs that are the max of the width/height so that all
//cells have the same size.
Spring maxWidthSpring = layout.getConstraints(parent.getComponent(0)).
getWidth();
Spring maxHeightSpring = layout.getConstraints(parent.getComponent(0)).
getWidth();
for (int i = 1; i < max; i++) {
SpringLayout.Constraints cons = layout.getConstraints(
parent.getComponent(i));
maxWidthSpring = Spring.max(maxWidthSpring, cons.getWidth());
maxHeightSpring = Spring.max(maxHeightSpring, cons.getHeight());
}
//Apply the new width/height Spring. This forces all the
//components to have the same size.
for (int i = 0; i < max; i++) {
SpringLayout.Constraints cons = layout.getConstraints(
parent.getComponent(i));
cons.setWidth(maxWidthSpring);
cons.setHeight(maxHeightSpring);
}
//Then adjust the x/y constraints of all the cells so that they
//are aligned in a grid.
SpringLayout.Constraints lastCons = null;
SpringLayout.Constraints lastRowCons = null;
for (int i = 0; i < max; i++) {
SpringLayout.Constraints cons = layout.getConstraints(
parent.getComponent(i));
if (i % cols == 0) { //start of new row
lastRowCons = lastCons;
cons.setX(initialXSpring);
} else { //x position depends on previous component
cons.setX(Spring.sum(lastCons.getConstraint(SpringLayout.EAST),
xPadSpring));
}
if (i / cols == 0) { //first row
cons.setY(initialYSpring);
} else { //y position depends on previous row
cons.setY(Spring.sum(lastRowCons.getConstraint(SpringLayout.SOUTH),
yPadSpring));
}
lastCons = cons;
}
//Set the parent's size.
SpringLayout.Constraints pCons = layout.getConstraints(parent);
pCons.setConstraint(SpringLayout.SOUTH,
Spring.sum(
Spring.constant(yPad),
lastCons.getConstraint(SpringLayout.SOUTH)));
pCons.setConstraint(SpringLayout.EAST,
Spring.sum(
Spring.constant(xPad),
lastCons.getConstraint(SpringLayout.EAST)));
}
/* Used by makeCompactGrid. */
private static SpringLayout.Constraints getConstraintsForCell(
int row, int col,
Container parent,
int cols) {
SpringLayout layout = (SpringLayout) parent.getLayout();
Component c = parent.getComponent(row * cols + col);
return layout.getConstraints(c);
}
/**
* Aligns the first <code>rows</code> * <code>cols</code>
* components of <code>parent</code> in
* a grid. Each component in a column is as wide as the maximum
* preferred width of the components in that column;
* height is similarly determined for each row.
* The parent is made just big enough to fit them all.
*
* @param rows number of rows
* @param cols number of columns
* @param initialX x location to start the grid at
* @param initialY y location to start the grid at
* @param xPad x padding between cells
* @param yPad y padding between cells
*/
public static void makeCompactGrid(Container parent,
int rows, int cols,
int initialX, int initialY,
int xPad, int yPad) {
SpringLayout layout;
try {
layout = (SpringLayout)parent.getLayout();
} catch (ClassCastException exc) {
System.err.println("The first argument to makeCompactGrid must use SpringLayout.");
return;
}
//Align all cells in each column and make them the same width.
Spring x = Spring.constant(initialX);
for (int c = 0; c < cols; c++) {
Spring width = Spring.constant(0);
for (int r = 0; r < rows; r++) {
width = Spring.max(width,
getConstraintsForCell(r, c, parent, cols).
getWidth());
}
for (int r = 0; r < rows; r++) {
SpringLayout.Constraints constraints =
getConstraintsForCell(r, c, parent, cols);
constraints.setX(x);
constraints.setWidth(width);
}
x = Spring.sum(x, Spring.sum(width, Spring.constant(xPad)));
}
//Align all cells in each row and make them the same height.
Spring y = Spring.constant(initialY);
for (int r = 0; r < rows; r++) {
Spring height = Spring.constant(0);
for (int c = 0; c < cols; c++) {
height = Spring.max(height,
getConstraintsForCell(r, c, parent, cols).
getHeight());
}
for (int c = 0; c < cols; c++) {
SpringLayout.Constraints constraints =
getConstraintsForCell(r, c, parent, cols);
constraints.setY(y);
constraints.setHeight(height);
}
y = Spring.sum(y, Spring.sum(height, Spring.constant(yPad)));
}
//Set the parent's size.
SpringLayout.Constraints pCons = layout.getConstraints(parent);
pCons.setConstraint(SpringLayout.SOUTH, y);
pCons.setConstraint(SpringLayout.EAST, x);
}
}
]]>