PrintPreview.java

import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.image.BufferedImage;
import java.awt.print.PageFormat;
import java.awt.print.Pageable;
import java.awt.print.Printable;
import java.awt.print.PrinterJob;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class PrintPreview extends JScrollPane{

	private static final long serialVersionUID = 1L;
	private Pageable mPageable = null;
	private double mScale = 1.0;
	private Page mPages[] = null;
	private CardLayout mCardLayout = new CardLayout();
	private JPanel mMainPanel = new JPanel(mCardLayout);
	private int mCurrentPage = 1;
	
	private JPanel mControls = null;
	private JButton mPrevButton = null;
	private JButton mNextButton = null;
	private JComboBox<String> mPagesCombo = null;
	private JSlider mZoomSlider = null;

	public PrintPreview(Pageable pg) {
		this.mPageable = pg;
		createPreview();
	}

	public PrintPreview(final Printable pr, final PageFormat p) {
		this.mPageable = new Pageable() {
			public int getNumberOfPages() {
				Graphics g = new java.awt.image.BufferedImage(2, 2,
						java.awt.image.BufferedImage.TYPE_INT_RGB)
						.getGraphics();
				int n = 0;
				try {
					while (pr.print(g, p, n) == Printable.PAGE_EXISTS)
						n++;
				} catch (Exception ex) {
					ex.printStackTrace();
				}
				return n;
			}

			public PageFormat getPageFormat(int x) {
				return p;
			}

			public Printable getPrintable(int x) {
				return pr;
			}
		};
		createPreview();
	}

	private void createPreview() {
		mPages = new Page[mPageable.getNumberOfPages()];
		PageFormat pf = mPageable.getPageFormat(0);
		Dimension size = new Dimension((int) pf.getPaper().getWidth(), (int) pf
				.getPaper().getHeight());
		if (pf.getOrientation() != PageFormat.PORTRAIT)
			size = new Dimension(size.height, size.width);

		for (int i = 0; i < mPages.length; i++) {
			mPages[i] = new Page(i, size);
			mMainPanel.add(String.valueOf(i + 1), mPages[i]);
		}
		
		setViewportView(mMainPanel);
		mPages[mCurrentPage-1].refreshScale();
	}

	private void setupControls(){
		
		mControls = new JPanel(new FlowLayout(FlowLayout.RIGHT));
		mPrevButton = new JButton("<<");
		mNextButton = new JButton(">>");
		mPagesCombo = new JComboBox<String>();
		mZoomSlider = new JSlider();
		for (int i = 0; i < mPages.length; i++) 
			mPagesCombo.addItem(String.valueOf(i+1));
		
		mPrevButton.setEnabled(false);
		mNextButton.setEnabled(mPages.length > 1);
		
		mPrevButton.addActionListener(new ActionListener() {
			
			@Override
			public void actionPerformed(ActionEvent arg0) {
				changePage(mCurrentPage-1);	
			}
		});
		
		mNextButton.addActionListener(new ActionListener() {
			
			@Override
			public void actionPerformed(ActionEvent e) {
				changePage(mCurrentPage+1);
			}
		});
		
		mPagesCombo.addItemListener(new ItemListener() {
			
			@Override
			public void itemStateChanged(ItemEvent arg0) {
				changePage(Integer.parseInt((String)mPagesCombo.getSelectedItem()));
			}
		});
		
		mZoomSlider.addChangeListener(new ChangeListener() {
			
			@Override
			public void stateChanged(ChangeEvent arg0) {
				double v = (double)mZoomSlider.getValue() / 10.0;
				zoom(v);
			}
		});
		
		mZoomSlider.setPaintTicks(true);
		//mZoomSlider.setPaintLabels(true);
		mZoomSlider.setMinimum(0);
		mZoomSlider.setMaximum(70);
		mZoomSlider.setValue(10);
		mZoomSlider.setSnapToTicks(true);
		mZoomSlider.setMinorTickSpacing(5);
		mZoomSlider.setMajorTickSpacing(10);
		
		mControls.add(mPrevButton);
		mControls.add(mPagesCombo);
		mControls.add(mNextButton);
		mControls.add(mZoomSlider);
	}
	
	/**
	 * Method lazy initializes JPanel with controls (if not initialized yet) and returns it
	 * @return panel with controls
	 */
	public JPanel getControls(){
		if(mControls == null)
			setupControls();
		
		return mControls;
	}

	/**
	 * Method changes current page, updates controls (if displayed) and returns true on success
	 * This method is safe, it checks if passed page number exists.
	 * 
	 * @param page number
	 * @return true if page was changed
	 */
	public boolean changePage(int page){
		
		if(mPages.length<page || page < 1 || mCurrentPage == page)
			return false;
		
		mCardLayout.show(mMainPanel, String.valueOf(page));
		getCurrentPageComponent().refreshScale();
		mCurrentPage = page;
		if(mPrevButton != null && mNextButton != null){
		    mPrevButton.setEnabled(mCurrentPage == 1 ? false : true);
		    mNextButton.setEnabled(mPages.length == page ? false:true);
		}
		if(mPagesCombo != null)
		    mPagesCombo.setSelectedItem(String.valueOf(page));
		    
		validate();
		return true;
	}
	
	/**
	 * Method checks if next page exists before processing
	 * 
	 * @return number of pages
	 */
	public int pages(){
		return mPages.length;
	}
	
	/**
	 * Method checks if previous page exists before processing.
	 * 
	 * @return true if page changed
	 */
	public boolean previousPage(){
		return changePage(mCurrentPage-1);
	}
	
	
	/**
	 * @return true if page changed
	 */
	public boolean nextPage(){
		return changePage(mCurrentPage+1);
	}
	
	/**
	 * Prints whole document
	 */
	public void print(){
		try {
			PrinterJob pj = PrinterJob.getPrinterJob();
			pj.defaultPage(mPageable.getPageFormat(0));
			pj.setPageable(mPageable);
			if (pj.printDialog())
				pj.print();
		} catch (Exception ex) {
			JOptionPane.showMessageDialog(null, ex.toString(),
					"Error in Printing", 1);
		}
	}

	/**
	 * Prints currently selected page
	 */
	public void printCurrentPage() {
		try {
			PrinterJob pj = PrinterJob.getPrinterJob();
			pj.defaultPage(mPageable.getPageFormat(0));
			pj.setPrintable(new PsuedoPrintable());
			javax.print.attribute.HashPrintRequestAttributeSet pra = new javax.print.attribute.HashPrintRequestAttributeSet();
			if (pj.printDialog(pra))
				pj.print(pra);
		} catch (Exception ex) {
			JOptionPane.showMessageDialog(null, ex.toString(),
					"Error in Printing", 1);
		}
	}
	
	/**
	 * Returns currently selected Page component
	 * 
	 * @return Page component
	 */
	public Page getCurrentPageComponent(){
		return mPages[mCurrentPage-1];
	}
	
	/**
	 * Return currently selected page's number
	 * 
	 * @return current page number
	 */
	public int getCurrentPage(){
		return mCurrentPage;
	}

	/**
	 * 
	 * 
	 * @param zoom double value greater than 0
	 */
	public void zoom(double zoom) {
		double temp = zoom;
		if (temp == mScale)
			return;
		if (temp == 0)
			temp = 0.01;
		
		
		mScale = temp;
		getCurrentPageComponent().refreshScale();
		this.validate();
	}

	class Page extends JLabel {

		private static final long serialVersionUID = 1L;
		private final int mPageNum;
		private final PageFormat mPageFormat;
		private BufferedImage mImage = null;
		private Dimension mSize = null;

		public Page(int x, Dimension size) {
			setHorizontalAlignment(JLabel.CENTER);
			mSize = size;
			mImage = new java.awt.image.BufferedImage(size.width, size.height,
					java.awt.image.BufferedImage.TYPE_INT_RGB);
			mPageNum = x;
			mPageFormat = mPageable.getPageFormat(mPageNum);
			
			
			Graphics g = mImage.getGraphics();
			Color c = g.getColor();
			g.setColor(Color.white);
			g.fillRect(0, 0, (int) mPageFormat.getWidth(), (int) mPageFormat.getHeight());
			g.setColor(c);
			try {
				//g.clipRect(0, 0, (int) pf.getWidth(), (int) pf.getHeight());
				mPageable.getPrintable(mPageNum).print(g, mPageFormat, mPageNum);
				g.setColor(Color.black);
				g.drawRect(0, 0, (int)mPageFormat.getWidth()-1, (int)mPageFormat.getHeight()-1);
			} catch (Exception ex) {
			}
			setIcon(new ImageIcon(mImage));
		}

		public void refreshScale() {
			
			if (mScale != 1.0){
				int w = (int) (mSize.width * mScale);
			    int h = (int) (mSize.height * mScale);
				setIcon(new ImageIcon(
						mImage.getScaledInstance(w, h, BufferedImage.SCALE_FAST)));				
			}else
				setIcon(new ImageIcon(mImage));
			
			validate();
		}
	}

	class PsuedoPrintable implements Printable {
		public int print(Graphics g, PageFormat fmt, int index) {
			if (index > 0)
				return Printable.NO_SUCH_PAGE;
			int n = mCurrentPage-1;
			try {
				return mPageable.getPrintable(n).print(g, fmt, n);
			} catch (Exception ex) {
			}
			return Printable.PAGE_EXISTS;
		}
	}
}