JXStripedList.java

package com.jakeapp.gui.swing.controls;

import org.jdesktop.swingx.JXList;

/**
 * A JList that supports a zebra stripe background.
 */
// TODO: use or delete
public class JXStripedList
		  extends JXList {
	private java.awt.Color rowColors[] = new java.awt.Color[2];
	private boolean drawStripes = false;

	public JXStripedList() {
	}

	public JXStripedList(javax.swing.ListModel dataModel) {
		super(dataModel);
	}

	public JXStripedList(Object[] listData) {
		super(listData);
	}

	public JXStripedList(java.util.Vector<?> listData) {
		super(listData);
	}

	/**
	 * Add zebra stripes to the background.
	 */
	@Override
	public void paintComponent(java.awt.Graphics g) {
		drawStripes = (getLayoutOrientation() == VERTICAL) && isOpaque();
		if (!drawStripes) {
			super.paintComponent(g);
			return;
		}

		// Paint zebra background stripes
		updateZebraColors();
		final java.awt.Insets insets = getInsets();
		final int w = getWidth() - insets.left - insets.right;
		final int h = getHeight() - insets.top - insets.bottom;
		final int x = insets.left;
		int y = insets.top;
		int nRows = 0;
		int startRow = 0;
		int rowHeight = getFixedCellHeight();
		if (rowHeight > 0)
			nRows = h / rowHeight;
		else {
			// Paint non-uniform height rows first
			final int nItems = getModel().getSize();
			rowHeight = 17; // A default for empty lists
			for (int i = 0; i < nItems; i++, y += rowHeight) {
				rowHeight = getCellBounds(i, i).height;
				g.setColor(rowColors[i & 1]);
				g.fillRect(x, y, w, rowHeight);
			}
			// Use last row height for remainder of list area
			nRows = nItems + (insets.top + h - y) / rowHeight;
			startRow = nItems;
		}
		for (int i = startRow; i < nRows; i++, y += rowHeight) {
			g.setColor(rowColors[i & 1]);
			g.fillRect(x, y, w, rowHeight);
		}
		final int remainder = insets.top + h - y;
		if (remainder > 0) {
			g.setColor(rowColors[nRows & 1]);
			g.fillRect(x, y, w, remainder);
		}

		// Paint component
		setOpaque(false);
		super.paintComponent(g);
		setOpaque(true);
	}

	/**
	 * Wrap a cell renderer to add zebra stripes behind list cells.
	 */
	private class RendererWrapper
			  implements javax.swing.ListCellRenderer {
		public javax.swing.ListCellRenderer ren = null;

		public java.awt.Component getListCellRendererComponent(
				  javax.swing.JList list, Object value, int index,
				  boolean isSelected, boolean cellHasFocus) {
			final java.awt.Component c = ren.getListCellRendererComponent(
					  list, value, index, isSelected, cellHasFocus);
			if (!isSelected && drawStripes)
				c.setBackground(rowColors[index & 1]);
			return c;
		}
	}

	private RendererWrapper wrapper = null;

	/**
	 * Return the wrapped cell renderer.
	 */
	@Override
	public javax.swing.ListCellRenderer getCellRenderer() {
		final javax.swing.ListCellRenderer ren = super.getCellRenderer();
		if (ren == null)
			return null;
		if (wrapper == null)
			wrapper = new RendererWrapper();
		wrapper.ren = ren;
		return wrapper;
	}

	/**
	 * Compute zebra background stripe colors.
	 */
	private void updateZebraColors() {
		if ((rowColors[0] = getBackground()) == null) {
			rowColors[0] = rowColors[1] = java.awt.Color.white;
			return;
		}
		final java.awt.Color sel = getSelectionBackground();
		if (sel == null) {
			rowColors[1] = rowColors[0];
			return;
		}
		final float[] bgHSB = java.awt.Color.RGBtoHSB(
				  rowColors[0].getRed(), rowColors[0].getGreen(),
				  rowColors[0].getBlue(), null);
		final float[] selHSB = java.awt.Color.RGBtoHSB(
				  sel.getRed(), sel.getGreen(), sel.getBlue(), null);
		rowColors[1] = java.awt.Color.getHSBColor(
				  (selHSB[1] == 0.0 || selHSB[2] == 0.0) ? bgHSB[0] : selHSB[0],
				  0.1f * selHSB[1] + 0.9f * bgHSB[1],
				  bgHSB[2] + ((bgHSB[2] < 0.5f) ? 0.05f : -0.05f));
	}
}