package be.nikiroo.utils; import java.awt.Component; import java.awt.Container; import java.awt.Dimension; import java.awt.FlowLayout; import java.awt.Insets; import javax.swing.JScrollPane; import javax.swing.SwingUtilities; /** * FlowLayout subclass that fully supports wrapping of components. * * @author https://tips4java.wordpress.com/2008/11/06/wrap-layout/ */ public class WrapLayout extends FlowLayout { private static final long serialVersionUID = 1L; /** * Constructs a new WrapLayout with a left alignment and a * default 5-unit horizontal and vertical gap. */ public WrapLayout() { super(); } /** * Constructs a new FlowLayout with the specified alignment and * a default 5-unit horizontal and vertical gap. The value of the alignment * argument must be one of WrapLayout, WrapLayout, * or WrapLayout. * * @param align * the alignment value */ public WrapLayout(int align) { super(align); } /** * Creates a new flow layout manager with the indicated alignment and the * indicated horizontal and vertical gaps. *

* The value of the alignment argument must be one of * WrapLayout, WrapLayout, or * WrapLayout. * * @param align * the alignment value * @param hgap * the horizontal gap between components * @param vgap * the vertical gap between components */ public WrapLayout(int align, int hgap, int vgap) { super(align, hgap, vgap); } /** * Returns the preferred dimensions for this layout given the visible * components in the specified target container. * * @param target * the component which needs to be laid out * @return the preferred dimensions to lay out the subcomponents of the * specified container */ @Override public Dimension preferredLayoutSize(Container target) { return layoutSize(target, true); } /** * Returns the minimum dimensions needed to layout the visible * components contained in the specified target container. * * @param target * the component which needs to be laid out * @return the minimum dimensions to lay out the subcomponents of the * specified container */ @Override public Dimension minimumLayoutSize(Container target) { Dimension minimum = layoutSize(target, false); minimum.width -= (getHgap() + 1); return minimum; } /** * Returns the minimum or preferred dimension needed to layout the target * container. * * @param target * target to get layout size for * @param preferred * should preferred size be calculated * @return the dimension to layout the target container */ private Dimension layoutSize(Container target, boolean preferred) { synchronized (target.getTreeLock()) { // Each row must fit with the width allocated to the containter. // When the container width = 0, the preferred width of the // container // has not yet been calculated so lets ask for the maximum. int targetWidth = target.getSize().width; Container container = target; while (container.getSize().width == 0 && container.getParent() != null) { container = container.getParent(); } targetWidth = container.getSize().width; if (targetWidth == 0) targetWidth = Integer.MAX_VALUE; int hgap = getHgap(); int vgap = getVgap(); Insets insets = target.getInsets(); int horizontalInsetsAndGap = insets.left + insets.right + (hgap * 2); int maxWidth = targetWidth - horizontalInsetsAndGap; // Fit components into the allowed width Dimension dim = new Dimension(0, 0); int rowWidth = 0; int rowHeight = 0; int nmembers = target.getComponentCount(); for (int i = 0; i < nmembers; i++) { Component m = target.getComponent(i); if (m.isVisible()) { Dimension d = preferred ? m.getPreferredSize() : m .getMinimumSize(); // Can't add the component to current row. Start a new // row. if (rowWidth + d.width > maxWidth) { addRow(dim, rowWidth, rowHeight); rowWidth = 0; rowHeight = 0; } // Add a horizontal gap for all components after the // first if (rowWidth != 0) { rowWidth += hgap; } rowWidth += d.width; rowHeight = Math.max(rowHeight, d.height); } } addRow(dim, rowWidth, rowHeight); dim.width += horizontalInsetsAndGap; dim.height += insets.top + insets.bottom + vgap * 2; // When using a scroll pane or the DecoratedLookAndFeel we need // to // make sure the preferred size is less than the size of the // target containter so shrinking the container size works // correctly. Removing the horizontal gap is an easy way to do // this. Container scrollPane = SwingUtilities.getAncestorOfClass( JScrollPane.class, target); if (scrollPane != null && target.isValid()) { dim.width -= (hgap + 1); } return dim; } } /* * A new row has been completed. Use the dimensions of this row to update * the preferred size for the container. * * @param dim update the width and height when appropriate * * @param rowWidth the width of the row to add * * @param rowHeight the height of the row to add */ private void addRow(Dimension dim, int rowWidth, int rowHeight) { dim.width = Math.max(dim.width, rowWidth); if (dim.height > 0) { dim.height += getVgap(); } dim.height += rowHeight; } }