1 /*
   2  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.awt;
  27 
  28 import java.awt.*;
  29 import java.awt.image.*;
  30 
  31 /**
  32  * A class to encapsulate a custom image-based cursor.
  33  *
  34  * @author      ThomasBall
  35  */
  36 @SuppressWarnings("serial") // JDK-implementation class
  37 public abstract class CustomCursor extends Cursor {
  38 
  39     protected Image image;
  40 
  41     public CustomCursor(Image cursor, Point hotSpot, String name)
  42             throws IndexOutOfBoundsException {
  43         super(name);
  44         image = cursor;
  45         Toolkit toolkit = Toolkit.getDefaultToolkit();
  46 
  47         // Make sure image is fully loaded.
  48         Component c = new Canvas(); // for its imageUpdate method
  49         MediaTracker tracker = new MediaTracker(c);
  50         tracker.addImage(cursor, 0);
  51         try {
  52             tracker.waitForAll();
  53         } catch (InterruptedException e) {
  54         }
  55         int width = cursor.getWidth(c);
  56         int height = cursor.getHeight(c);
  57 
  58         // Fix for bug 4212593 The Toolkit.createCustomCursor does not
  59         //                     check absence of the image of cursor
  60         // If the image is invalid, the cursor will be hidden (made completely
  61         // transparent). In this case, getBestCursorSize() will adjust negative w and h,
  62         // but we need to set the hotspot inside the image here.
  63         if (tracker.isErrorAny() || width < 0 || height < 0) {
  64               hotSpot.x = hotSpot.y = 0;
  65         }
  66 
  67         // Scale image to nearest supported size.
  68         Dimension nativeSize = toolkit.getBestCursorSize(width, height);
  69         if (nativeSize.width != width || nativeSize.height != height) {
  70             cursor = cursor.getScaledInstance(nativeSize.width,
  71                                               nativeSize.height,
  72                                               Image.SCALE_DEFAULT);
  73             width = nativeSize.width;
  74             height = nativeSize.height;
  75         }
  76 
  77         // Verify that the hotspot is within cursor bounds.
  78         if (hotSpot.x >= width || hotSpot.y >= height || hotSpot.x < 0 || hotSpot.y < 0) {
  79             throw new IndexOutOfBoundsException("invalid hotSpot");
  80         }
  81 
  82         /* Extract ARGB array from image.
  83          *
  84          * A transparency mask can be created in native code by checking
  85          * each pixel's top byte -- a 0 value means the pixel's transparent.
  86          * Since each platform's format of the bitmap and mask are likely to
  87          * be different, their creation shouldn't be here.
  88          */
  89         int[] pixels = new int[width * height];
  90         ImageProducer ip = cursor.getSource();
  91         PixelGrabber pg = new PixelGrabber(ip, 0, 0, width, height,
  92                                            pixels, 0, width);
  93         try {
  94             pg.grabPixels();
  95         } catch (InterruptedException e) {
  96         }
  97 
  98         createNativeCursor(image, pixels, width, height, hotSpot.x, hotSpot.y);
  99     }
 100 
 101     protected abstract void createNativeCursor(Image im,  int[] pixels,
 102                                                int width, int height,
 103                                                int xHotSpot, int yHotSpot);
 104 }