Worked on creating GUI

Added GUI (generated using NetBeans). Added support for callbacks
into the GUI specifically related to the wanted viewer operations.

6 files changed, 585 insertions, 12 deletions

diff --git a/demos/java/gsviewer/src/com/artifex/gsviewer/Document.java b/demos/java/gsviewer/src/com/artifex/gsviewer/Document.java
index c40c9bcbc..2d5035e19 100644
--- a/demos/java/gsviewer/src/com/artifex/gsviewer/Document.java
+++ b/demos/java/gsviewer/src/com/artifex/gsviewer/Document.java
@@ -23,6 +23,35 @@ public class Document implements List<Page> {
 	private static final DocumentLoader documentLoader = new DocumentLoader();
 	private static final int format = GS_COLORS_RGB | GS_DISPLAY_DEPTH_8 | GS_DISPLAY_BIGENDIAN;
 
+	public static void loadDocumentAsync(final File file, final DocAsyncLoadCallback cb)
+			throws NullPointerException {
+		Objects.requireNonNull(cb, "DocAsyncLoadCallback");
+		final Thread t = new Thread(() -> {
+			Document doc = null;
+			Exception exception = null;
+			try {
+				doc = new Document(file);
+			} catch (FileNotFoundException | IllegalStateException | NullPointerException e) {
+				exception = e;
+			}
+			cb.onDocumentLoad(doc, exception);
+		});
+		t.setName("Document-Loader-Thread");
+		t.setDaemon(true);
+		t.start();
+	}
+
+	public static void loadDocumentAsync(final String filename, final DocAsyncLoadCallback cb)
+			throws NullPointerException {
+		loadDocumentAsync(new File(filename), cb);
+	}
+
+	@FunctionalInterface
+	public static interface DocAsyncLoadCallback {
+
+		public void onDocumentLoad(Document doc, Exception exception);
+	}
+
 	private static void initDocInstance(LongReference instanceRef) throws IllegalStateException {
 		int code = gsapi_new_instance(instanceRef, GS_NULL);
 		if (code != GS_ERROR_OK) {
diff --git a/demos/java/gsviewer/src/com/artifex/gsviewer/GSFileFilter.java b/demos/java/gsviewer/src/com/artifex/gsviewer/GSFileFilter.java
new file mode 100644
index 000000000..6136e973b
--- /dev/null
+++ b/demos/java/gsviewer/src/com/artifex/gsviewer/GSFileFilter.java
@@ -0,0 +1,35 @@
+package com.artifex.gsviewer;
+
+import java.io.File;
+
+import javax.swing.filechooser.FileFilter;
+
+public class GSFileFilter extends FileFilter {
+
+	public static final GSFileFilter INSTANCE = new GSFileFilter();
+
+	@Override
+	public boolean accept(File f) {
+		if (f.isDirectory())
+			return true;
+		final String name = f.getName();
+		final int ind = name.lastIndexOf('.');
+		final String ext = name.substring(ind);
+		return
+			equals(ext, "pdf") ||
+			equals(ext, "eps") ||
+			equals(ext, "ps") ||
+			equals(ext, "xps") ||
+			equals(ext, "oxps") ||
+			equals(ext, "bin");
+	}
+
+	@Override
+	public String getDescription() {
+		return "Ghostscript Files";
+	}
+
+	private boolean equals(String extension, String compare) {
+		return extension.equalsIgnoreCase(compare);
+	}
+}
diff --git a/demos/java/gsviewer/src/com/artifex/gsviewer/Main.java b/demos/java/gsviewer/src/com/artifex/gsviewer/Main.java
index e3cc84fd4..b1c3014e9 100644
--- a/demos/java/gsviewer/src/com/artifex/gsviewer/Main.java
+++ b/demos/java/gsviewer/src/com/artifex/gsviewer/Main.java
@@ -5,24 +5,42 @@ import java.io.FileNotFoundException;
 import java.io.IOException;
 
 import javax.imageio.ImageIO;
+import javax.swing.SwingUtilities;
+import javax.swing.UIManager;
+import javax.swing.UnsupportedLookAndFeelException;
+
+import com.artifex.gsviewer.gui.ViewerWindow;
 
 public class Main {
 
 	public static void main(String[] args) throws FileNotFoundException {
-		Document doc = new Document("010104_momentum_concepts.pdf");
+		try {
+			UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
+		} catch (ClassNotFoundException | InstantiationException | IllegalAccessException
+				| UnsupportedLookAndFeelException e1) {
+			e1.printStackTrace();
+		}
+
+		ViewerWindow win = new ViewerWindow(new ViewerGUIListenerImpl());
+		SwingUtilities.invokeLater(() -> {
+			win.setVisible(true);
+		});
+
+
+		//Document doc = new Document("010104_momentum_concepts.pdf");
 		//doc.loadHighRes(1, 3);
 		//doc.unloadHighRes(2);
-		doc.loadHighResList(1, 2, 3);
-
-		int pageNum = 1;
-		for (Page page : doc) {
-			try {
-				ImageIO.write(page.getDisplayableImage(), "PNG", new File("page-" + pageNum + ".png"));
-			} catch (IOException e) {
-				System.err.println("Failed to write page " + pageNum);
-			}
-			pageNum++;
-		}
+		//doc.loadHighResList(1, 2, 3);
+
+		//int pageNum = 1;
+		//for (Page page : doc) {
+		//	try {
+		//		ImageIO.write(page.getDisplayableImage(), "PNG", new File("page-" + pageNum + ".png"));
+		//	} catch (IOException e) {
+		//		System.err.println("Failed to write page " + pageNum);
+		//	}
+		//	pageNum++;
+		//}
 
 	}
 }
diff --git a/demos/java/gsviewer/src/com/artifex/gsviewer/ViewerGUIListenerImpl.java b/demos/java/gsviewer/src/com/artifex/gsviewer/ViewerGUIListenerImpl.java
new file mode 100644
index 000000000..108be1974
--- /dev/null
+++ b/demos/java/gsviewer/src/com/artifex/gsviewer/ViewerGUIListenerImpl.java
@@ -0,0 +1,67 @@
+package com.artifex.gsviewer;
+
+import java.awt.Point;
+import java.io.File;
+
+import javax.swing.JFileChooser;
+import javax.swing.JOptionPane;
+
+import com.artifex.gsviewer.gui.ViewerGUIListener;
+import com.artifex.gsviewer.gui.ViewerWindow;
+
+public class ViewerGUIListenerImpl implements ViewerGUIListener {
+
+	@Override
+	public void onPageChange(ViewerWindow source, int oldPage, int newPage) {
+		System.out.println("Page change: " + oldPage + " to " + newPage);
+	}
+
+	@Override
+	public void onZoomChange(ViewerWindow source, double oldZoom, double newZoom) {
+		System.out.println("Zoom change: " + oldZoom + " to " + newZoom);
+	}
+
+	@Override
+	public void onScrollChange(ViewerWindow source, Point oldScroll, Point newScroll) {
+		System.out.println("Scroll change: " + oldScroll + " to " + newScroll);
+	}
+
+	@Override
+	public void onOpenFile(ViewerWindow source) {
+		System.out.println("Open file");
+		JFileChooser chooser = new JFileChooser();
+		chooser.setFileFilter(GSFileFilter.INSTANCE);
+		chooser.setCurrentDirectory(new File("").getAbsoluteFile());
+		int status = chooser.showOpenDialog(source);
+		if (status == JFileChooser.APPROVE_OPTION) {
+			File toOpen = chooser.getSelectedFile();
+			System.out.println("To open: " + toOpen.getAbsolutePath());
+			Document.loadDocumentAsync(toOpen, (final Document doc, final Exception exception) -> {
+				if (exception != null) {
+					JOptionPane.showMessageDialog(source, exception.toString(),
+							"Failed to load", JOptionPane.ERROR_MESSAGE);
+				} else {
+					System.out.println("Loaded document");
+				}
+			});
+		}
+	}
+
+	@Override
+	public void onCloseFile(ViewerWindow source) {
+		System.out.println("Close file");
+	}
+
+	@Override
+	public void onClosing(ViewerWindow source) {
+		System.out.println("Closing");
+		source.dispose();
+		System.exit(0);
+	}
+
+	@Override
+	public void onSettingsOpen(ViewerWindow source) {
+		System.out.println("Settings open");
+	}
+
+}
diff --git a/demos/java/gsviewer/src/com/artifex/gsviewer/gui/ViewerGUIListener.java b/demos/java/gsviewer/src/com/artifex/gsviewer/gui/ViewerGUIListener.java
new file mode 100644
index 000000000..f56bbc5cb
--- /dev/null
+++ b/demos/java/gsviewer/src/com/artifex/gsviewer/gui/ViewerGUIListener.java
@@ -0,0 +1,20 @@
+package com.artifex.gsviewer.gui;
+
+import java.awt.Point;
+
+public interface ViewerGUIListener {
+
+	public void onPageChange(ViewerWindow source, int oldPage, int newPage);
+
+	public void onZoomChange(ViewerWindow source, double oldZoom, double newZoom);
+
+	public void onScrollChange(ViewerWindow source, Point oldScroll, Point newScroll);
+
+	public void onOpenFile(ViewerWindow source);
+
+	public void onCloseFile(ViewerWindow source);
+
+	public void onClosing(ViewerWindow source);
+
+	public void onSettingsOpen(ViewerWindow source);
+}
diff --git a/demos/java/gsviewer/src/com/artifex/gsviewer/gui/ViewerWindow.java b/demos/java/gsviewer/src/com/artifex/gsviewer/gui/ViewerWindow.java
new file mode 100644
index 000000000..ca144d683
--- /dev/null
+++ b/demos/java/gsviewer/src/com/artifex/gsviewer/gui/ViewerWindow.java
@@ -0,0 +1,404 @@
+package com.artifex.gsviewer.gui;
+
+/**
+ * Auto-generated form using NetBeans.
+ */
+public class ViewerWindow extends javax.swing.JFrame {
+
+	private static final long serialVersionUID = 1L;
+
+	private ViewerGUIListener guiListener;
+	private int currentPage, maxPage;
+	private double currentZoom;
+
+	/**
+	 * Creates new form ViewerWindow
+	 */
+	public ViewerWindow() {
+		this(null);
+	}
+
+	public ViewerWindow(final ViewerGUIListener listener) {
+		initComponents();
+		this.guiListener = listener;
+		this.currentPage = 0;
+		this.maxPage = 0;
+		this.currentZoom = 1.0;
+	}
+
+	/**
+	 * This method is called from within the constructor to initialize the form.
+	 * WARNING: Do NOT modify this code. The content of this method is always
+	 * regenerated by the Form Editor.
+	 */
+	@SuppressWarnings("unchecked")
+	// <editor-fold defaultstate="collapsed" desc="Generated
+	// Code">//GEN-BEGIN:initComponents
+	private void initComponents() {
+
+        viewerScrollPane = new javax.swing.JScrollPane();
+        viewerContentPane = new javax.swing.JPanel();
+        miniViewerScrollPane = new javax.swing.JScrollPane();
+        miniViewerContentPane = new javax.swing.JPanel();
+        zoomSlider = new javax.swing.JSlider();
+        increaseZoomButton = new javax.swing.JButton();
+        decreaseZoomButton = new javax.swing.JButton();
+        lastPageButton = new javax.swing.JButton();
+        maxPagesLabel = new javax.swing.JTextField();
+        nextPageButton = new javax.swing.JButton();
+        progressBar = new javax.swing.JProgressBar();
+        pageNumberField = new javax.swing.JTextField();
+        pageSlashLabel = new javax.swing.JLabel();
+        menuBar = new javax.swing.JMenuBar();
+        fileMenu = new javax.swing.JMenu();
+        openMenu = new javax.swing.JMenuItem();
+        closeMenuItem = new javax.swing.JMenuItem();
+        fileMenuSeparator = new javax.swing.JPopupMenu.Separator();
+        exitMenuItem = new javax.swing.JMenuItem();
+        editMenu = new javax.swing.JMenu();
+        settingsMenuItem = new javax.swing.JMenuItem();
+
+        setDefaultCloseOperation(javax.swing.WindowConstants.DO_NOTHING_ON_CLOSE);
+        setTitle("Viewer");
+        setMinimumSize(new java.awt.Dimension(640, 650));
+        addWindowListener(new java.awt.event.WindowAdapter() {
+            @Override
+			public void windowClosing(java.awt.event.WindowEvent evt) {
+                formWindowClosing(evt);
+            }
+        });
+
+        viewerScrollPane.setMinimumSize(new java.awt.Dimension(85, 110));
+
+        javax.swing.GroupLayout viewerContentPaneLayout = new javax.swing.GroupLayout(viewerContentPane);
+        viewerContentPane.setLayout(viewerContentPaneLayout);
+        viewerContentPaneLayout.setHorizontalGroup(
+            viewerContentPaneLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+            .addGap(0, 502, Short.MAX_VALUE)
+        );
+        viewerContentPaneLayout.setVerticalGroup(
+            viewerContentPaneLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+            .addGap(0, 639, Short.MAX_VALUE)
+        );
+
+        viewerScrollPane.setViewportView(viewerContentPane);
+
+        miniViewerScrollPane.setHorizontalScrollBarPolicy(javax.swing.ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
+
+        javax.swing.GroupLayout miniViewerContentPaneLayout = new javax.swing.GroupLayout(miniViewerContentPane);
+        miniViewerContentPane.setLayout(miniViewerContentPaneLayout);
+        miniViewerContentPaneLayout.setHorizontalGroup(
+            miniViewerContentPaneLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+            .addGap(0, 118, Short.MAX_VALUE)
+        );
+        miniViewerContentPaneLayout.setVerticalGroup(
+            miniViewerContentPaneLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+            .addGap(0, 639, Short.MAX_VALUE)
+        );
+
+        miniViewerScrollPane.setViewportView(miniViewerContentPane);
+
+        zoomSlider.setMajorTickSpacing(25);
+        zoomSlider.setMinorTickSpacing(5);
+        zoomSlider.setPaintTicks(true);
+        zoomSlider.setSnapToTicks(true);
+        zoomSlider.addMouseListener(new java.awt.event.MouseAdapter() {
+            @Override
+			public void mouseReleased(java.awt.event.MouseEvent evt) {
+                zoomSliderMouseReleased(evt);
+            }
+        });
+
+        increaseZoomButton.setText("+");
+        increaseZoomButton.addActionListener(new java.awt.event.ActionListener() {
+            @Override
+			public void actionPerformed(java.awt.event.ActionEvent evt) {
+                increaseZoomButtonActionPerformed(evt);
+            }
+        });
+
+        decreaseZoomButton.setText("-");
+        decreaseZoomButton.addActionListener(new java.awt.event.ActionListener() {
+            @Override
+			public void actionPerformed(java.awt.event.ActionEvent evt) {
+                decreaseZoomButtonActionPerformed(evt);
+            }
+        });
+
+        lastPageButton.setText("<");
+        lastPageButton.addActionListener(new java.awt.event.ActionListener() {
+            @Override
+			public void actionPerformed(java.awt.event.ActionEvent evt) {
+                lastPageButtonActionPerformed(evt);
+            }
+        });
+
+        maxPagesLabel.setEditable(false);
+        maxPagesLabel.setText("0");
+
+        nextPageButton.setText(">");
+        nextPageButton.addActionListener(new java.awt.event.ActionListener() {
+            @Override
+			public void actionPerformed(java.awt.event.ActionEvent evt) {
+                nextPageButtonActionPerformed(evt);
+            }
+        });
+
+        pageNumberField.setText("0");
+        pageNumberField.addKeyListener(new java.awt.event.KeyAdapter() {
+            @Override
+			public void keyPressed(java.awt.event.KeyEvent evt) {
+                pageNumberFieldKeyPressed(evt);
+            }
+        });
+
+        pageSlashLabel.setText("/");
+
+        fileMenu.setText("File");
+
+        openMenu.setText("Open");
+        openMenu.addActionListener(new java.awt.event.ActionListener() {
+            @Override
+			public void actionPerformed(java.awt.event.ActionEvent evt) {
+                openMenuActionPerformed(evt);
+            }
+        });
+        fileMenu.add(openMenu);
+
+        closeMenuItem.setText("Close");
+        closeMenuItem.addActionListener(new java.awt.event.ActionListener() {
+            @Override
+			public void actionPerformed(java.awt.event.ActionEvent evt) {
+                closeMenuItemActionPerformed(evt);
+            }
+        });
+        fileMenu.add(closeMenuItem);
+        fileMenu.add(fileMenuSeparator);
+
+        exitMenuItem.setText("Exit");
+        exitMenuItem.addActionListener(new java.awt.event.ActionListener() {
+            @Override
+			public void actionPerformed(java.awt.event.ActionEvent evt) {
+                exitMenuItemActionPerformed(evt);
+            }
+        });
+        fileMenu.add(exitMenuItem);
+
+        menuBar.add(fileMenu);
+
+        editMenu.setText("Edit");
+
+        settingsMenuItem.setText("Settings");
+        settingsMenuItem.addActionListener(new java.awt.event.ActionListener() {
+            @Override
+			public void actionPerformed(java.awt.event.ActionEvent evt) {
+                settingsMenuItemActionPerformed(evt);
+            }
+        });
+        editMenu.add(settingsMenuItem);
+
+        menuBar.add(editMenu);
+
+        setJMenuBar(menuBar);
+
+        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
+        getContentPane().setLayout(layout);
+        layout.setHorizontalGroup(
+            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+            .addGroup(layout.createSequentialGroup()
+                .addContainerGap()
+                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+                    .addComponent(progressBar, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
+                    .addGroup(layout.createSequentialGroup()
+                        .addComponent(miniViewerScrollPane, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE)
+                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
+                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+                            .addGroup(layout.createSequentialGroup()
+                                .addGap(2, 2, 2)
+                                .addComponent(decreaseZoomButton, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)
+                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
+                                .addComponent(zoomSlider, javax.swing.GroupLayout.PREFERRED_SIZE, 111, javax.swing.GroupLayout.PREFERRED_SIZE)
+                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
+                                .addComponent(increaseZoomButton)
+                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
+                                .addComponent(lastPageButton)
+                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
+                                .addComponent(pageNumberField, javax.swing.GroupLayout.PREFERRED_SIZE, 45, javax.swing.GroupLayout.PREFERRED_SIZE)
+                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
+                                .addComponent(pageSlashLabel)
+                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
+                                .addComponent(maxPagesLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 47, javax.swing.GroupLayout.PREFERRED_SIZE)
+                                .addGap(4, 4, 4)
+                                .addComponent(nextPageButton)
+                                .addGap(2, 2, 2))
+                            .addComponent(viewerScrollPane, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))))
+                .addContainerGap())
+        );
+        layout.setVerticalGroup(
+            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+            .addGroup(layout.createSequentialGroup()
+                .addContainerGap()
+                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+                    .addComponent(miniViewerScrollPane)
+                    .addComponent(viewerScrollPane, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
+                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
+                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
+                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
+                        .addComponent(decreaseZoomButton)
+                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
+                            .addComponent(increaseZoomButton)
+                            .addComponent(nextPageButton)
+                            .addComponent(maxPagesLabel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
+                            .addComponent(pageNumberField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
+                            .addComponent(lastPageButton)
+                            .addComponent(pageSlashLabel)))
+                    .addComponent(zoomSlider, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
+                .addGap(14, 14, 14)
+                .addComponent(progressBar, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
+                .addContainerGap())
+        );
+
+        pack();
+    }// </editor-fold>
+
+	private void lastPageButtonActionPerformed(java.awt.event.ActionEvent evt) {// GEN-FIRST:event_lastPageButtonActionPerformed
+		if (maxPage > 0) {
+			final int oldPage = currentPage;
+			currentPage = Math.max(currentPage - 1, 1);
+			pageNumberField.setText(new StringBuilder().append(currentPage).toString());
+			if (guiListener != null)
+				guiListener.onPageChange(this, oldPage, currentPage);
+		} else {
+			pageNumberField.setText(new StringBuilder().append(0).toString());
+		}
+	}// GEN-LAST:event_lastPageButtonActionPerformed
+
+	private void nextPageButtonActionPerformed(java.awt.event.ActionEvent evt) {// GEN-FIRST:event_nextPageButtonActionPerformed
+		if (maxPage > 0) {
+			final int oldPage = currentPage;
+			currentPage = Math.min(currentPage + 1, maxPage);
+			pageNumberField.setText(new StringBuilder().append(currentPage).toString());
+			if (guiListener != null)
+				guiListener.onPageChange(this, oldPage, currentPage);
+		} else {
+			pageNumberField.setText(new StringBuilder().append(0).toString());
+		}
+	}// GEN-LAST:event_nextPageButtonActionPerformed
+
+	private void formWindowClosing(java.awt.event.WindowEvent evt) {// GEN-FIRST:event_formWindowClosing
+		if (guiListener != null)
+			guiListener.onClosing(this);
+	}// GEN-LAST:event_formWindowClosing
+
+	private void pageNumberFieldKeyPressed(java.awt.event.KeyEvent evt) {// GEN-FIRST:event_pageNumberFieldKeyPressed
+		if (evt.getKeyCode() == java.awt.event.KeyEvent.VK_ENTER) {
+			final String text = pageNumberField.getText();
+			try {
+				final int newPage = Integer.parseInt(text);
+				if (newPage < 1 || newPage > maxPage)
+					throw new IllegalArgumentException();
+				final int oldPage = currentPage;
+				this.currentPage = newPage;
+				if (guiListener != null)
+					guiListener.onPageChange(this, oldPage, currentPage);
+			} catch (IllegalArgumentException e) {
+				System.err.println(new StringBuilder().append("Invalid page number \"").
+						append(text).append('\"').toString());
+			} finally {
+				pageNumberField.setText(new StringBuilder().append(currentPage).toString());
+			}
+		}
+	}// GEN-LAST:event_pageNumberFieldKeyPressed
+
+	private void zoomSliderMouseReleased(java.awt.event.MouseEvent evt) {// GEN-FIRST:event_zoomSliderMouseReleased
+		final double sliderValue = zoomSlider.getValue() / 50.0;
+		final double oldZoom = currentZoom;
+		this.currentZoom = sliderValue;
+		if (guiListener != null && oldZoom != currentZoom)
+			guiListener.onZoomChange(this, oldZoom, currentZoom);
+	}// GEN-LAST:event_zoomSliderMouseReleased
+
+	private void increaseZoomButtonActionPerformed(java.awt.event.ActionEvent evt) {// GEN-FIRST:event_increaseZoomButtonActionPerformed
+		final double oldZoom = currentZoom;
+		this.currentZoom = Math.min(Math.ceil((oldZoom * 10) + 1) / 10, 2.0);
+		zoomSlider.setValue((int)(currentZoom * 50));
+		if (guiListener != null && oldZoom != currentZoom)
+			guiListener.onZoomChange(this, oldZoom, currentZoom);
+	}// GEN-LAST:event_increaseZoomButtonActionPerformed
+
+	private void decreaseZoomButtonActionPerformed(java.awt.event.ActionEvent evt) {// GEN-FIRST:event_decreaseZoomButtonActionPerformed
+		final double oldZoom = currentZoom;
+		this.currentZoom = Math.max(Math.floor((oldZoom * 10) - 1) / 10, 0.0);
+		zoomSlider.setValue((int)(currentZoom * 50));
+		if (guiListener != null && oldZoom != currentZoom)
+			guiListener.onZoomChange(this, oldZoom, currentZoom);
+	}// GEN-LAST:event_decreaseZoomButtonActionPerformed
+
+	private void openMenuActionPerformed(java.awt.event.ActionEvent evt) {// GEN-FIRST:event_openMenuActionPerformed
+		if (guiListener != null)
+			guiListener.onOpenFile(this);
+	}// GEN-LAST:event_openMenuActionPerformed
+
+	private void closeMenuItemActionPerformed(java.awt.event.ActionEvent evt) {// GEN-FIRST:event_closeMenuItemActionPerformed
+		if (guiListener != null)
+			guiListener.onCloseFile(this);
+	}// GEN-LAST:event_closeMenuItemActionPerformed
+
+	private void exitMenuItemActionPerformed(java.awt.event.ActionEvent evt) {// GEN-FIRST:event_exitMenuItemActionPerformed
+		if (guiListener != null)
+			guiListener.onClosing(this);
+	}// GEN-LAST:event_exitMenuItemActionPerformed
+
+	private void settingsMenuItemActionPerformed(java.awt.event.ActionEvent evt) {// GEN-FIRST:event_settingsMenuItemActionPerformed
+		if (guiListener != null)
+			guiListener.onSettingsOpen(this);
+	}// GEN-LAST:event_settingsMenuItemActionPerformed
+
+	// Variables declaration - do not modify//GEN-BEGIN:variables
+	private javax.swing.JMenuItem closeMenuItem;
+	private javax.swing.JButton decreaseZoomButton;
+	private javax.swing.JMenu editMenu;
+	private javax.swing.JMenuItem exitMenuItem;
+	private javax.swing.JMenu fileMenu;
+	private javax.swing.JPopupMenu.Separator fileMenuSeparator;
+	private javax.swing.JButton increaseZoomButton;
+	private javax.swing.JButton lastPageButton;
+	private javax.swing.JTextField maxPagesLabel;
+	private javax.swing.JMenuBar menuBar;
+	private javax.swing.JPanel miniViewerContentPane;
+	private javax.swing.JScrollPane miniViewerScrollPane;
+	private javax.swing.JButton nextPageButton;
+	private javax.swing.JMenuItem openMenu;
+	private javax.swing.JTextField pageNumberField;
+	private javax.swing.JLabel pageSlashLabel;
+	private javax.swing.JProgressBar progressBar;
+	private javax.swing.JMenuItem settingsMenuItem;
+	private javax.swing.JPanel viewerContentPane;
+	private javax.swing.JScrollPane viewerScrollPane;
+	private javax.swing.JSlider zoomSlider;
+	// End of variables declaration//GEN-END:variables
+
+	public void setGUIListener(final ViewerGUIListener listener) {
+		this.guiListener = listener;
+	}
+
+	public void setPage(final int newPage) {
+		try {
+			if (newPage < 1 || newPage > maxPage)
+				throw new IllegalArgumentException();
+			final int oldPage = currentPage;
+			currentPage = newPage;
+			if (guiListener != null)
+				guiListener.onPageChange(this, oldPage, currentPage);
+		} catch (IllegalArgumentException e) {
+			System.err.println(new StringBuilder().append("Invalid page number \"").
+					append(newPage).append('\"').toString());
+		} finally {
+			pageNumberField.setText(new StringBuilder().append(currentPage).toString());
+		}
+	}
+
+	public void setMaxPage(final int max) {
+		this.maxPage = max;
+	}
+}