examples/JexerImageViewer.java

   1 import java.awt.image.BufferedImage;
   2 import java.io.File;
   3 import java.io.IOException;
   4 import java.util.ArrayList;
   5 import java.util.List;
   6 import javax.imageio.ImageIO;
   7
   8 import jexer.TAction;
   9 import jexer.TApplication;
  10 import jexer.TDesktop;
  11 import jexer.TDirectoryList;
  12 import jexer.TImage;
  13 import jexer.backend.SwingTerminal;
  14 import jexer.bits.CellAttributes;
  15 import jexer.bits.GraphicsChars;
  16 import jexer.event.TKeypressEvent;
  17 import jexer.event.TResizeEvent;
  18 import jexer.menu.TMenu;
  19 import jexer.ttree.TDirectoryTreeItem;
  20 import jexer.ttree.TTreeItem;
  21 import jexer.ttree.TTreeViewWidget;
  22 import static jexer.TKeypress.*;
  23
  24 /**
  25  * Implements a simple image thumbnail file viewer.  Much of this code was
  26  * stripped down from TFileOpenBox.
  27  */
  28 public class JexerImageViewer extends TApplication {
  29
  30     /**
  31      * Main entry point.
  32      */
  33     public static void main(String [] args) throws Exception {
  34         JexerImageViewer app = new JexerImageViewer();
  35         (new Thread(app)).start();
  36     }
  37
  38     /**
  39      * Public constructor chooses the ECMA-48 / Xterm backend.
  40      */
  41     public JexerImageViewer() throws Exception {
  42         super(BackendType.XTERM);
  43
  44         // The stock tool menu has items for redrawing the screen, opening
  45         // images, and (when using the Swing backend) setting the font.
  46         addToolMenu();
  47
  48         // We will have one menu containing a mix of new and stock commands
  49         TMenu fileMenu = addMenu("&File");
  50
  51         // Stock commands: a new shell, exit program.
  52         fileMenu.addDefaultItem(TMenu.MID_SHELL);
  53         fileMenu.addSeparator();
  54         fileMenu.addDefaultItem(TMenu.MID_EXIT);
  55
  56         // Filter the files list to support image suffixes only.
  57         List<String> filters = new ArrayList<String>();
  58         filters.add("^.*\\.[Jj][Pp][Gg]$");
  59         filters.add("^.*\\.[Jj][Pp][Ee][Gg]$");
  60         filters.add("^.*\\.[Pp][Nn][Gg]$");
  61         filters.add("^.*\\.[Gg][Ii][Ff]$");
  62         filters.add("^.*\\.[Bb][Mm][Pp]$");
  63         setDesktop(new ImageViewerDesktop(this, ".", filters));
  64     }
  65
  66 }
  67
  68 /**
  69  * The desktop contains a tree view on the left, list of files on the top
  70  * right, and image view on the bottom right.
  71  */
  72 class ImageViewerDesktop extends TDesktop {
  73
  74     /**
  75      * The left-side tree view pane.
  76      */
  77     private TTreeViewWidget treeView;
  78
  79     /**
  80      * The data behind treeView.
  81      */
  82     private TDirectoryTreeItem treeViewRoot;
  83
  84     /**
  85      * The top-right-side directory list pane.
  86      */
  87     private TDirectoryList directoryList;
  88
  89     /**
  90      * The bottom-right-side image pane.
  91      */
  92     private TImage imageWidget;
  93
  94     /**
  95      * Public constructor.
  96      *
  97      * @param application the TApplication that manages this window
  98      * @param path path of selected file
  99      * @param filters a list of strings that files must match to be displayed
 100      * @throws IOException of a java.io operation throws
 101      */
 102     public ImageViewerDesktop(final TApplication application, final String path,
 103         final List<String> filters) throws IOException {
 104
 105         super(application);
 106         setActive(true);
 107
 108         // Add directory treeView
 109         treeView = addTreeViewWidget(0, 0, getWidth() / 2, getHeight() - 1,
 110             new TAction() {
 111                 public void DO() {
 112                     TTreeItem item = treeView.getSelected();
 113                     File selectedDir = ((TDirectoryTreeItem) item).getFile();
 114                     try {
 115                         directoryList.setPath(selectedDir.getCanonicalPath());
 116                         if (directoryList.getList().size() > 0) {
 117                             setThumbnail(directoryList.getPath());
 118                         } else {
 119                             if (imageWidget != null) {
 120                                 getChildren().remove(imageWidget);
 121                             }
 122                             imageWidget = null;
 123                         }
 124                         activate(treeView);
 125                     } catch (IOException e) {
 126                         // If the backend is Swing, we can emit the stack
 127                         // trace to stderr.  Otherwise, just squash it.
 128                         if (getScreen() instanceof SwingTerminal) {
 129                             e.printStackTrace();
 130                         }
 131                     }
 132                 }
 133             }
 134         );
 135         treeViewRoot = new TDirectoryTreeItem(treeView, path, true);
 136
 137         // Add directory files list
 138         directoryList = addDirectoryList(path, getWidth() / 2 + 1, 0,
 139             getWidth() / 2 - 1, getHeight() / 2,
 140
 141             new TAction() {
 142                 public void DO() {
 143                     setThumbnail(directoryList.getPath());
 144                 }
 145             },
 146             new TAction() {
 147
 148                 public void DO() {
 149                     setThumbnail(directoryList.getPath());
 150                 }
 151             },
 152             filters);
 153
 154         // This appears to be a bug.  If I pass keystrokes to the tree view,
 155         // it will center correctly.
 156         treeView.onKeypress(new TKeypressEvent(kbDown));
 157         treeView.onKeypress(new TKeypressEvent(kbUp));
 158
 159         if (directoryList.getList().size() > 0) {
 160             activate(directoryList);
 161             setThumbnail(directoryList.getPath());
 162         } else {
 163             activate(treeView);
 164         }
 165     }
 166
 167     /**
 168      * Handle window/screen resize events.
 169      *
 170      * @param event resize event
 171      */
 172     @Override
 173     public void onResize(final TResizeEvent event) {
 174
 175         // Resize the tree and list
 176         treeView.setY(1);
 177         treeView.setWidth(getWidth() / 2);
 178         treeView.setHeight(getHeight() - 1);
 179         treeView.onResize(new TResizeEvent(TResizeEvent.Type.WIDGET,
 180                 treeView.getWidth(),
 181                 treeView.getHeight()));
 182         treeView.getTreeView().onResize(new TResizeEvent(TResizeEvent.Type.WIDGET,
 183                 treeView.getWidth() - 1,
 184                 treeView.getHeight() - 1));
 185         directoryList.setX(getWidth() / 2 + 1);
 186         directoryList.setY(1);
 187         directoryList.setWidth(getWidth() / 2 - 1);
 188         directoryList.setHeight(getHeight() / 2 - 1);
 189         directoryList.onResize(new TResizeEvent(TResizeEvent.Type.WIDGET,
 190                 directoryList.getWidth(),
 191                 directoryList.getHeight()));
 192
 193         // Recreate the image
 194         if (imageWidget != null) {
 195             getChildren().remove(imageWidget);
 196         }
 197         imageWidget = null;
 198         if (directoryList.getList().size() > 0) {
 199             activate(directoryList);
 200             setThumbnail(directoryList.getPath());
 201         } else {
 202             activate(treeView);
 203         }
 204     }
 205
 206     /**
 207      * Handle keystrokes.
 208      *
 209      * @param keypress keystroke event
 210      */
 211     @Override
 212     public void onKeypress(final TKeypressEvent keypress) {
 213
 214         if (treeView.isActive() || directoryList.isActive()) {
 215             if ((keypress.equals(kbEnter))
 216                 || (keypress.equals(kbUp))
 217                 || (keypress.equals(kbDown))
 218                 || (keypress.equals(kbPgUp))
 219                 || (keypress.equals(kbPgDn))
 220                 || (keypress.equals(kbHome))
 221                 || (keypress.equals(kbEnd))
 222             ) {
 223                 // Tree view will be changing, update the directory list.
 224                 super.onKeypress(keypress);
 225
 226                 // This is the same action as treeView's enter.
 227                 TTreeItem item = treeView.getSelected();
 228                 File selectedDir = ((TDirectoryTreeItem) item).getFile();
 229                 try {
 230                     if (treeView.isActive()) {
 231                         directoryList.setPath(selectedDir.getCanonicalPath());
 232                     }
 233                     if (directoryList.getList().size() > 0) {
 234                         activate(directoryList);
 235                         setThumbnail(directoryList.getPath());
 236                     } else {
 237                         if (imageWidget != null) {
 238                             getChildren().remove(imageWidget);
 239                         }
 240                         imageWidget = null;
 241                         activate(treeView);
 242                     }
 243                 } catch (IOException e) {
 244                     // If the backend is Swing, we can emit the stack trace
 245                     // to stderr.  Otherwise, just squash it.
 246                     if (getScreen() instanceof SwingTerminal) {
 247                         e.printStackTrace();
 248                     }
 249                 }
 250                 return;
 251             }
 252         }
 253
 254         // Pass to my parent
 255         super.onKeypress(keypress);
 256     }
 257
 258     /**
 259      * Draw me on screen.
 260      */
 261     @Override
 262     public void draw() {
 263         CellAttributes background = getTheme().getColor("tdesktop.background");
 264         putAll(' ', background);
 265
 266         vLineXY(getWidth() / 2, 0, getHeight(),
 267             GraphicsChars.WINDOW_SIDE, getBackground());
 268
 269         hLineXY(getWidth() / 2, getHeight() / 2, (getWidth() + 1) / 2,
 270             GraphicsChars.WINDOW_TOP, getBackground());
 271
 272         putCharXY(getWidth() / 2, getHeight() / 2,
 273             GraphicsChars.WINDOW_LEFT_TEE, getBackground());
 274     }
 275
 276     /**
 277      * Set the image thumbnail.
 278      *
 279      * @param file the image file
 280      */
 281     private void setThumbnail(final File file) {
 282         if (file == null) {
 283             return;
 284         }
 285         if (!file.exists() || !file.isFile()) {
 286             return;
 287         }
 288
 289         BufferedImage image = null;
 290         try {
 291             image = ImageIO.read(file);
 292         } catch (IOException e) {
 293             // If the backend is Swing, we can emit the stack trace to
 294             // stderr.  Otherwise, just squash it.
 295             if (getScreen() instanceof SwingTerminal) {
 296                 e.printStackTrace();
 297             }
 298             return;
 299         }
 300
 301         if (imageWidget != null) {
 302             getChildren().remove(imageWidget);
 303         }
 304         int width = getWidth() / 2 - 1;
 305         int height = getHeight() / 2 - 1;
 306
 307         imageWidget = new TImage(this, getWidth() - width,
 308             getHeight() - height, width, height, image, 0, 0, null);
 309
 310         // Resize the image down until it can fit within the pane.
 311         while ((imageWidget.getRows() > height)
 312             || (imageWidget.getColumns() > width)
 313         ) {
 314             imageWidget.onKeypress(new TKeypressEvent(kbAltDown));
 315         }
 316
 317         imageWidget.setActive(false);
 318         activate(directoryList);
 319     }
 320
 321 }