src/jexer/bits/Clipboard.java

   1 /*
   2  * Jexer - Java Text User Interface
   3  *
   4  * The MIT License (MIT)
   5  *
   6  * Copyright (C) 2019 Kevin Lamonte
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  24  * DEALINGS IN THE SOFTWARE.
  25  *
  26  * @author Kevin Lamonte [kevin.lamonte@gmail.com]
  27  * @version 1
  28  */
  29 package jexer.bits;
  30
  31 import java.awt.Image;
  32 import java.awt.Toolkit;
  33 import java.awt.datatransfer.DataFlavor;
  34 import java.awt.datatransfer.StringSelection;
  35 import java.awt.datatransfer.Transferable;
  36 import java.awt.datatransfer.UnsupportedFlavorException;
  37 import java.awt.image.BufferedImage;
  38 import java.io.IOException;
  39
  40 /**
  41  * Clipboard provides convenience methods to copy text and images to and from
  42  * a shared clipboard.  When the system clipboard is available it is used.
  43  */
  44 public class Clipboard {
  45
  46     // ------------------------------------------------------------------------
  47     // Variables --------------------------------------------------------------
  48     // ------------------------------------------------------------------------
  49
  50     /**
  51      * The image last copied to the clipboard.
  52      */
  53     private BufferedImage image = null;
  54
  55     /**
  56      * The text string last copied to the clipboard.
  57      */
  58     private String text = null;
  59
  60     /**
  61      * The system clipboard, or null if it is not available.
  62      */
  63     private java.awt.datatransfer.Clipboard systemClipboard = null;
  64
  65     /**
  66      * The image selection class.
  67      */
  68     private ImageSelection imageSelection;
  69
  70     /**
  71      * ImageSelection is used to hold an image while on the clipboard.
  72      */
  73     private class ImageSelection implements Transferable {
  74
  75         /**
  76          * Returns an array of DataFlavor objects indicating the flavors the
  77          * data can be provided in. The array should be ordered according to
  78          * preference for providing the data (from most richly descriptive to
  79          * least descriptive).
  80          *
  81          * @return an array of data flavors in which this data can be
  82          * transferred
  83          */
  84         public DataFlavor[] getTransferDataFlavors() {
  85             return new DataFlavor[] { DataFlavor.imageFlavor };
  86         }
  87
  88         /**
  89          * Returns whether or not the specified data flavor is supported for
  90          * this object.
  91          *
  92          * @param flavor the requested flavor for the data
  93          * @return boolean indicating whether or not the data flavor is
  94          * supported
  95          */
  96         public boolean isDataFlavorSupported(DataFlavor flavor) {
  97             return DataFlavor.imageFlavor.equals(flavor);
  98         }
  99
 100         /**
 101          * Returns an object which represents the data to be transferred. The
 102          * class of the object returned is defined by the representation
 103          * class of the flavor.
 104          *
 105          * @param flavor the requested flavor for the data
 106          * @throws IOException if the data is no longer available in the
 107          * requested flavor.
 108          * @throws UnsupportedFlavorException if the requested data flavor is
 109          * not supported.
 110          */
 111         public Object getTransferData(DataFlavor flavor)
 112                 throws UnsupportedFlavorException, IOException {
 113
 114             if (!DataFlavor.imageFlavor.equals(flavor)) {
 115                 throw new UnsupportedFlavorException(flavor);
 116             }
 117             return image;
 118         }
 119     }
 120
 121     // ------------------------------------------------------------------------
 122     // Constructors -----------------------------------------------------------
 123     // ------------------------------------------------------------------------
 124
 125     /**
 126      * Public constructor.
 127      */
 128     public Clipboard() {
 129         try {
 130             systemClipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
 131         } catch (java.awt.HeadlessException e) {
 132             // SQUASH
 133         }
 134     }
 135
 136     // ------------------------------------------------------------------------
 137     // Clipboard --------------------------------------------------------------
 138     // ------------------------------------------------------------------------
 139
 140     /**
 141      * Copy an image to the clipboard.
 142      *
 143      * @param image image to copy
 144      */
 145     public void copyImage(final BufferedImage image) {
 146         this.image = image;
 147         if (systemClipboard != null) {
 148             ImageSelection imageSelection = new ImageSelection();
 149             systemClipboard.setContents(imageSelection, null);
 150         }
 151     }
 152
 153     /**
 154      * Copy a text string to the clipboard.
 155      *
 156      * @param text string to copy
 157      */
 158     public void copyText(final String text) {
 159         this.text = text;
 160         if (systemClipboard != null) {
 161             StringSelection stringSelection = new StringSelection(text);
 162             systemClipboard.setContents(stringSelection, null);
 163         }
 164     }
 165
 166     /**
 167      * Obtain an image from the clipboard.
 168      *
 169      * @return image from the clipboard, or null if no image is available
 170      */
 171     public BufferedImage pasteImage() {
 172         if (systemClipboard != null) {
 173             getClipboardImage();
 174         }
 175         return image;
 176     }
 177
 178     /**
 179      * Obtain a text string from the clipboard.
 180      *
 181      * @return text string from the clipboard, or null if no text is
 182      * available
 183      */
 184     public String pasteText() {
 185         if (systemClipboard != null) {
 186             getClipboardText();
 187         }
 188         return text;
 189     }
 190
 191     /**
 192      * Returns true if the clipboard has an image.
 193      *
 194      * @return true if an image is available from the clipboard
 195      */
 196     public boolean isImage() {
 197         if (image == null) {
 198             getClipboardImage();
 199         }
 200         return (image != null);
 201     }
 202
 203     /**
 204      * Returns true if the clipboard has a text string.
 205      *
 206      * @return true if a text string is available from the clipboard
 207      */
 208     public boolean isText() {
 209         if (text == null) {
 210             getClipboardText();
 211         }
 212         return (text != null);
 213     }
 214
 215     /**
 216      * Returns true if the clipboard is empty.
 217      *
 218      * @return true if the clipboard is empty
 219      */
 220     public boolean isEmpty() {
 221         return ((isText() == false) && (isImage() == false));
 222     }
 223
 224     /**
 225      * Copy image from the clipboard to text.
 226      */
 227     private void getClipboardImage() {
 228         if (systemClipboard != null) {
 229             Transferable contents = systemClipboard.getContents(null);
 230             if (contents != null) {
 231                 if (contents.isDataFlavorSupported(DataFlavor.imageFlavor)) {
 232                     try {
 233                         Image img = (Image) contents.getTransferData(DataFlavor.imageFlavor);
 234                         image = new BufferedImage(img.getWidth(null),
 235                             img.getHeight(null), BufferedImage.TYPE_INT_ARGB);
 236                         image.getGraphics().drawImage(img, 0, 0, null);
 237                     } catch (IOException e) {
 238                         // SQUASH
 239                     } catch (UnsupportedFlavorException e) {
 240                         // SQUASH
 241                     }
 242                 }
 243             }
 244         }
 245     }
 246
 247     /**
 248      * Copy text string from the clipboard to text.
 249      */
 250     private void getClipboardText() {
 251         if (systemClipboard != null) {
 252             Transferable contents = systemClipboard.getContents(null);
 253             if (contents != null) {
 254                 if (contents.isDataFlavorSupported(DataFlavor.stringFlavor)) {
 255                     try {
 256                         text = (String) contents.getTransferData(DataFlavor.stringFlavor);
 257                     } catch (IOException e) {
 258                         // SQUASH
 259                     } catch (UnsupportedFlavorException e) {
 260                         // SQUASH
 261                     }
 262                 }
 263             }
 264         }
 265     }
 266
 267     /**
 268      * Clear whatever is on the local clipboard.  Note that this will not
 269      * clear the system clipboard.
 270      */
 271     public void clear() {
 272         image = null;
 273         text = null;
 274     }
 275
 276 }