Updated how zooming is handled

Zooming is now done through the SmartLoader and is no longer
a separate operation. Fixed an issue when the SmartLoader could
become out of date due to the condition variable being signaled
before the SmartLoader had finished.

4 files changed, 137 insertions, 122 deletions

diff --git a/demos/java/gsviewer/src/com/artifex/gsviewer/DefaultUnhandledExceptionHandler.java b/demos/java/gsviewer/src/com/artifex/gsviewer/DefaultUnhandledExceptionHandler.java
index 9e31a2e03..6ae6389fe 100644
--- a/demos/java/gsviewer/src/com/artifex/gsviewer/DefaultUnhandledExceptionHandler.java
+++ b/demos/java/gsviewer/src/com/artifex/gsviewer/DefaultUnhandledExceptionHandler.java
@@ -4,6 +4,10 @@ import java.io.ByteArrayOutputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.PrintStream;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.Enumeration;
+import java.util.Properties;
 
 public class DefaultUnhandledExceptionHandler implements Thread.UncaughtExceptionHandler {
 
@@ -22,7 +26,38 @@ public class DefaultUnhandledExceptionHandler implements Thread.UncaughtExceptio
 	public void uncaughtException(Thread t, Throwable e) {
 		StringBuilder builder = new StringBuilder();
 
+		DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy/MM/dd HH:mm:ss");
 		builder.append("Unhandled exception!\n");
+
+		//builder.append("USER\n");
+		builder.append("Time: " + dtf.format(LocalDateTime.now()) + "\n\n");
+
+		builder.append("PROPERTIES\n");
+		Properties props = System.getProperties();
+		for (Enumeration<Object> keys = props.keys(); keys.hasMoreElements();) {
+			String key = keys.nextElement().toString();
+			String prop = props.getProperty(key);
+			String friendly = "\"";
+			for (int i = 0; i < prop.length(); i++) {
+				char c = prop.charAt(i);
+				switch (c) {
+				case '\n':
+					friendly += "\\n";
+					break;
+				case '\r':
+					friendly += "\\r";
+					break;
+				default:
+					friendly += c;
+					break;
+				}
+			}
+			friendly += "\"";
+			builder.append(key + " = " + friendly + "\n");
+		}
+		builder.append('\n');
+
+		builder.append("EXCEPTION\n");
 		builder.append("Exception: " + e.getClass().getName() + "\n");
 		builder.append("Message: " + e.getMessage() + "\n");
 		builder.append("Cause: " + (e.getCause() == null ? "[Unknown]" :
@@ -30,6 +65,7 @@ public class DefaultUnhandledExceptionHandler implements Thread.UncaughtExceptio
 		builder.append("Thread: " + t.getName() + " (id=" + t.getId() + ")\n");
 		builder.append("Stack trace:" + "\n");
 		builder.append(stackTraceToString(e));
+
 		String fullMessage = builder.toString();
 		System.err.println(fullMessage);
 		try {
diff --git a/demos/java/gsviewer/src/com/artifex/gsviewer/Document.java b/demos/java/gsviewer/src/com/artifex/gsviewer/Document.java
index 5e2c4af91..4b07c5b8d 100644
--- a/demos/java/gsviewer/src/com/artifex/gsviewer/Document.java
+++ b/demos/java/gsviewer/src/com/artifex/gsviewer/Document.java
@@ -231,11 +231,6 @@ public class Document implements List<Page> {
 
 			if (code != GS_ERROR_OK)
 				throw new IllegalStateException("Failed to distill document (code = " + code + ")");
-
-			/*Reference<Integer> pExitCode = new Reference<>();
-			int code = gsInstance.run_file(out.getAbsolutePath(), 0, pExitCode);
-			if (code != GS_ERROR_OK)
-				throw new IllegalStateException("failed to run file (code = " + code + ")");*/
 		} finally {
 			deleteGSInstance();
 		}
@@ -682,77 +677,6 @@ public class Document implements List<Page> {
 	}
 
 	/**
-	 * Loads the high resolution images of a list of pages.
-	 *
-	 * @param operationMode How the loader should behave if an operation is already in
-	 * progress. Can be <code>OPERATION_WAIT</code>, meaning the loader should
-	 * wait until a running operation has finished, <code>OPERATION_RETURN</code> meaning
-	 * the loader should immediately return, or <code>OPERATION_THROW</code> meaning the loader
-	 * should throw an <code>OperationInProgressException</code>.
-	 * @param pages The pages to load.
-	 *
-	 * @throws IndexOutOfBoundsException When any page is not a page in the document.
-	 * @throws IllegalStateException When Ghostscript fails to initialize or load the document.
-	 * @throws OperationInProgressException When an operation is already in progress
-	 * and <code>operationMode</code> is <code>OPERATION_THROW</code>.
-	 * @throws IllegalArgumentException When <code>operationMode</code> is not
-	 * <code>OPERATION_WAIT</coded>, <code>OPERATION_RETURN</code>, or <code>OPERATION_THROW</code>.
-	 */
-	public void loadHighResList(int operationMode, final int[] pages)
-			throws IndexOutOfBoundsException, IllegalStateException, OperationInProgressException {
-		throw new UnsupportedOperationException("loadHighResList");
-		/*if (pages.length > 0) {
-			if (!handleOperationMode(operationMode))
-				return;
-
-			try {
-				startOperation();
-
-				final StringBuilder builder = new StringBuilder();
-				if (pages[0] < 1 || pages[0] > this.pages.size())
-					throw new IndexOutOfBoundsException("page=" + pages[0]);
-				builder.append(pages[0]);
-
-				for (int i = 1; i < pages.length; i++) {
-					if (pages[i] < 1 || pages[i] > this.pages.size())
-						throw new IndexOutOfBoundsException("page=" + pages[i]);
-					builder.append(',').append(pages[i]);
-				}
-
-
-				final String[] gargs = { "gs", "-dNOPAUSE", "-dSAFER", "-I%rom%Resource%/Init/", "-dBATCH", "-r" + Page.PAGE_HIGH_DPI,
-						"-sDEVICE=display", "-sPageList=" + builder.toString(), "-dDisplayFormat=" + format,
-						"-dTextAlphaBits=4", "-dGraphicsAlphaBits=4",
-						"-f", file.getAbsolutePath() };
-
-				GSInstance instance = null;
-				try {
-					instance = initDocInstance();
-				} catch (IllegalStateException e) {
-					operationDone();
-				}
-
-				if (instance == null)
-					throw new IllegalStateException("Failed to initialize Ghoscript");
-
-				int code = instance.init_with_args(gargs);
-				instance.exit();
-				instance.delete_instance();
-				if (code != GS_ERROR_OK) {
-					throw new IllegalStateException("Failed to gsapi_init_with_args code=" + code);
-				}
-
-				int ind = 0;
-				for (final BufferedImage img : documentLoader.images) {
-					this.pages.get(pages[ind] - 1).setHighRes(img);
-				}
-			} finally {
-				operationDone();
-			}
-		}*/
-	}
-
-	/**
 	 * Unloads the high resolution images in a range of pages.
 	 *
 	 * @param startPage The start page to unload the high resolution image from.
@@ -885,6 +809,34 @@ public class Document implements List<Page> {
 		}
 	}
 
+	public void zoomPage(final int operationMode, final int page, final double zoom)
+		throws IndexOutOfBoundsException {
+		checkBounds(page, page);
+
+		if (!handleOperationMode(operationMode))
+			return;
+
+		try {
+			startOperation();
+
+			setParams((int)(Page.PAGE_HIGH_DPI * zoom), page, page);
+
+			Reference<Integer> exitCode = new Reference<>();
+			int code = gsInstance.run_file(file.getAbsolutePath(), 0, exitCode);
+
+			if (code != GS_ERROR_OK)
+				throw new IllegalStateException("Failed to run file (code = " + code + ")");
+
+			int ind = page - 1;
+			for (final BufferedImage img : documentLoader.images) {
+				this.pages.get(ind++).setZoomed(img);
+			}
+
+		} finally {
+			operationDone();
+		}
+	}
+
 	/**
 	 * Checks to make sure the pages <code>start</code> through
 	 * <code>end</code> are in the document, and throws an
diff --git a/demos/java/gsviewer/src/com/artifex/gsviewer/ViewerController.java b/demos/java/gsviewer/src/com/artifex/gsviewer/ViewerController.java
index 39b3aae7f..f062ab949 100644
--- a/demos/java/gsviewer/src/com/artifex/gsviewer/ViewerController.java
+++ b/demos/java/gsviewer/src/com/artifex/gsviewer/ViewerController.java
@@ -24,6 +24,7 @@ public class ViewerController implements ViewerGUIListener {
 
 	private static final Lock lock = new ReentrantLock();
 	private static final Condition cv = lock.newCondition();
+	private static volatile boolean outOfDate = true;
 
 	private ViewerWindow source;
 	private Document currentDocument;
@@ -38,10 +39,14 @@ public class ViewerController implements ViewerGUIListener {
 				try {
 					JFileChooser chooser = new JFileChooser();
 					chooser.setCurrentDirectory(new File("."));
+					chooser.setFileFilter(PDFFileFilter.INSTANCE);
 					ret = chooser.showSaveDialog(source);
 					if (ret != JFileChooser.APPROVE_OPTION)
 						return;
 					File out = chooser.getSelectedFile();
+					String filepath = out.getAbsolutePath();
+					if (filepath.lastIndexOf('.') == -1)
+						out = new File(filepath + ".pdf");
 					if (out.exists()) {
 						ret = source.showConfirmDialog("Overwrite?", out.getName() + " already exists. Overwrite?");
 						if (ret != ViewerWindow.YES)
@@ -98,46 +103,21 @@ public class ViewerController implements ViewerGUIListener {
 
 	@Override
 	public void onPageChange(int oldPage, int newPage) {
-		lock.lock();
-		try {
-			cv.signalAll();
-		} catch (IllegalMonitorStateException e) {
-			System.err.println("Exception on signaling: " + e);
-		} finally {
-			lock.unlock();
-		}
+		smartLoader.signalOutOfDate();
 	}
 
 	@Override
 	public void onZoomChange(double oldZoom, double newZoom) {
 		if (newZoom > 1.0) {
-			int currentPage = source.getCurrentPage();
-			Runnable r = () -> {
-					//source.showWarningDialog("Error", "An operation is already in progress");
-					//return;
-
-				try {
-					currentDocument.zoomArea(Document.OPERATION_THROW, currentPage, newZoom);
-				} catch (Document.OperationInProgressException e) {
-					source.showWarningDialog("Error", "An operation is already in progress");
-				}
-			};
-			Thread t = new Thread(r);
-			t.setName("Zoom-Thread");
-			t.start();
+			smartLoader.resetZoom();
+			smartLoader.signalOutOfDate();
 		}
 	}
 
 	@Override
 	public void onScrollChange(int newScroll) {
-		lock.lock();
-		try {
-			cv.signalAll();
-		} catch (IllegalMonitorStateException e) {
-			System.err.println("Exception on signaling: " + e);
-		} finally {
-			lock.unlock();
-		}
+		if (smartLoader != null)
+			smartLoader.signalOutOfDate();
 	}
 
 	@Override
@@ -184,7 +164,6 @@ public class ViewerController implements ViewerGUIListener {
 				source.showErrorDialog("Unhandled Exception", errorMessage);
 			}
 			DefaultUnhandledExceptionHandler.INSTANCE.uncaughtException(t, e);
-
 		}
 
 	}
@@ -192,15 +171,17 @@ public class ViewerController implements ViewerGUIListener {
 	private class SmartLoader implements Runnable {
 
 		private volatile boolean[] loaded;
+		private volatile boolean[] zoomLoaded;
 		private volatile boolean shouldRun;
 		private Thread thread;
 
-		private SmartLoader(Document doc) {
+		SmartLoader(Document doc) {
 			loaded = new boolean[doc.size()];
+			zoomLoaded = new boolean[doc.size()];
 			shouldRun = true;
 		}
 
-		private void start() {
+		void start() {
 			if (thread != null)
 				stop();
 			shouldRun = true;
@@ -210,11 +191,12 @@ public class ViewerController implements ViewerGUIListener {
 			thread.start();
 		}
 
-		private void stop() {
-			shouldRun = false;
+		void stop() {
 			lock.lock();
 			cv.signalAll();
 			lock.unlock();
+			outOfDate = false;
+			shouldRun = false;
 			try {
 				thread.join();
 			} catch (InterruptedException e) {
@@ -223,6 +205,24 @@ public class ViewerController implements ViewerGUIListener {
 			thread = null;
 		}
 
+		void resetZoom() {
+			for (int i = 0; i < zoomLoaded.length; i++) {
+				zoomLoaded[i] = false;
+			}
+		}
+
+		void signalOutOfDate() {
+			outOfDate = true;
+			lock.lock();
+			try {
+				cv.signalAll();
+			} catch (IllegalMonitorStateException e) {
+				System.err.println("Exception on signaling: " + e);
+			} finally {
+				lock.unlock();
+			}
+		}
+
 		@Override
 		public void run() {
 			System.out.println("Smart loader dispatched.");
@@ -238,9 +238,23 @@ public class ViewerController implements ViewerGUIListener {
 				int ind = 0;
 				for (int page : toLoad) {
 					if (page >= 1 && page <= currentDocument.size()) {
-						if (!loaded[page - 1]) {
-							currentDocument.loadHighRes(Document.OPERATION_WAIT, page);
-							loaded[page - 1] = true;
+						if (source.getZoom() > 1.0) {
+
+							// Load the zoomed page view only if it has not already been loaded.
+							if (!zoomLoaded[page - 1]) {
+								currentDocument.zoomArea(Document.OPERATION_WAIT, page, source.getZoom());
+								zoomLoaded[page - 1] = true;
+							}
+						} else {
+
+							// Unload any zoomed image to save memory consumption
+							currentDocument.unloadZoomed(page);
+
+							// Load the high-resolution page view only if it has not already been loaded
+							if (!loaded[page - 1]) {
+								currentDocument.loadHighRes(Document.OPERATION_WAIT, page);
+								loaded[page - 1] = true;
+							}
 						}
 					}
 					ind++;
@@ -248,13 +262,20 @@ public class ViewerController implements ViewerGUIListener {
 				}
 				source.setLoadProgress(0);
 
-				lock.lock();
-				try {
-					cv.await();
-				} catch (InterruptedException e) {
-					System.err.println("Interrupted in smart loader: " + e);
-				} finally {
-					lock.unlock();
+				// First check if the current view is out of date and if so, just immediately continue
+				// so the thread does not get stuck in the lock until another event has occurred.
+				if (!outOfDate) {
+					outOfDate = false;
+					lock.lock();
+					try {
+						cv.await();
+					} catch (InterruptedException e) {
+						System.err.println("Interrupted in smart loader: " + e);
+					} finally {
+						lock.unlock();
+					}
+				} else {
+					outOfDate = false;
 				}
 			}
 		}
diff --git a/demos/java/gsviewer/src/com/artifex/gsviewer/gui/ViewerWindow.java b/demos/java/gsviewer/src/com/artifex/gsviewer/gui/ViewerWindow.java
index 0b701ddc3..9ada11a62 100644
--- a/demos/java/gsviewer/src/com/artifex/gsviewer/gui/ViewerWindow.java
+++ b/demos/java/gsviewer/src/com/artifex/gsviewer/gui/ViewerWindow.java
@@ -496,8 +496,10 @@ public class ViewerWindow extends javax.swing.JFrame {
 					img = page.getZoomedImage();
 
 				Image result = img;
-				if (img == page.getLowResImage() || currentZoom < 1.0)
+				if (img == page.getLowResImage() || currentZoom < 1.0 ||
+						(img == page.getHighResImage() && currentZoom > 1.0 && page.getZoomedImage() == null)) {
 					result = img.getScaledInstance(actualSize.width, actualSize.height, Image.SCALE_FAST);
+				}
 				return result;
 			} else {
 				return null;
@@ -790,6 +792,10 @@ public class ViewerWindow extends javax.swing.JFrame {
 		return JOptionPane.showConfirmDialog(this, message, title, JOptionPane.YES_NO_CANCEL_OPTION);
 	}
 
+	public double getZoom() {
+		return currentZoom;
+	}
+
 	/**
 	 * Refresh each button's state.
 	 */