bundles/org.eclipse.swt.win32.win32.x86_64/src/org/eclipse/swt/dnd/TreeDragSourceEffect.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2012 IBM Corporation and others.
   3  *
   4  * This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License 2.0
   6  * which accompanies this distribution, and is available at
   7  * https://www.eclipse.org/legal/epl-2.0/
   8  *
   9  * SPDX-License-Identifier: EPL-2.0
  10  *
  11  * Contributors:
  12  *     IBM Corporation - initial API and implementation
  13  *******************************************************************************/
  14 package org.eclipse.swt.dnd;
  15
  16 import org.eclipse.swt.*;
  17 import org.eclipse.swt.graphics.*;
  18 import org.eclipse.swt.internal.*;
  19 import org.eclipse.swt.internal.DPIUtil.*;
  20 import org.eclipse.swt.internal.win32.*;
  21 import org.eclipse.swt.widgets.*;
  22
  23 /**
  24  * This class provides default implementations to display a source image
  25  * when a drag is initiated from a <code>Tree</code>.
  26  *
  27  * <p>Classes that wish to provide their own source image for a <code>Tree</code> can
  28  * extend <code>TreeDragSourceEffect</code> class and override the <code>TreeDragSourceEffect.dragStart</code>
  29  * method and set the field <code>DragSourceEvent.image</code> with their own image.</p>
  30  *
  31  * Subclasses that override any methods of this class must call the corresponding
  32  * <code>super</code> method to get the default drag under effect implementation.
  33  *
  34  * @see DragSourceEffect
  35  * @see DragSourceEvent
  36  * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
  37  *
  38  * @since 3.3
  39  */
  40 public class TreeDragSourceEffect extends DragSourceEffect {
  41         Image dragSourceImage = null;
  42
  43         /**
  44          * Creates a new <code>TreeDragSourceEffect</code> to handle drag effect
  45          * from the specified <code>Tree</code>.
  46          *
  47          * @param tree the <code>Tree</code> that the user clicks on to initiate the drag
  48          */
  49         public TreeDragSourceEffect(Tree tree) {
  50                 super(tree);
  51         }
  52
  53         /**
  54          * This implementation of <code>dragFinished</code> disposes the image
  55          * that was created in <code>TreeDragSourceEffect.dragStart</code>.
  56          *
  57          * Subclasses that override this method should call <code>super.dragFinished(event)</code>
  58          * to dispose the image in the default implementation.
  59          *
  60          * @param event the information associated with the drag finished event
  61          */
  62         @Override
  63         public void dragFinished(DragSourceEvent event) {
  64                 if (dragSourceImage != null) dragSourceImage.dispose();
  65                 dragSourceImage = null;
  66         }
  67
  68         /**
  69          * This implementation of <code>dragStart</code> will create a default
  70          * image that will be used during the drag. The image should be disposed
  71          * when the drag is completed in the <code>TreeDragSourceEffect.dragFinished</code>
  72          * method.
  73          *
  74          * Subclasses that override this method should call <code>super.dragStart(event)</code>
  75          * to use the image from the default implementation.
  76          *
  77          * @param event the information associated with the drag start event
  78          */
  79         @Override
  80         public void dragStart(DragSourceEvent event) {
  81                 event.image = getDragSourceImage(event);
  82         }
  83
  84         Image getDragSourceImage(DragSourceEvent event) {
  85                 if (dragSourceImage != null) dragSourceImage.dispose();
  86                 dragSourceImage = null;
  87                 SHDRAGIMAGE shdi = new SHDRAGIMAGE();
  88                 int DI_GETDRAGIMAGE = OS.RegisterWindowMessage (new TCHAR (0, "ShellGetDragImage", true)); //$NON-NLS-1$
  89                 if (OS.SendMessage (control.handle, DI_GETDRAGIMAGE, 0, shdi) != 0) {
  90                         if ((control.getStyle() & SWT.MIRRORED) != 0) {
  91                                 event.offsetX = shdi.sizeDragImage.cx - shdi.ptOffset.x;
  92                         } else {
  93                                 event.offsetX = shdi.ptOffset.x;
  94                         }
  95                         event.offsetY = shdi.ptOffset.y;
  96                         long hImage = shdi.hbmpDragImage;
  97                         if (hImage != 0) {
  98                                 BITMAP bm = new BITMAP ();
  99                                 OS.GetObject (hImage, BITMAP.sizeof, bm);
 100                                 int srcWidth = bm.bmWidth;
 101                                 int srcHeight = bm.bmHeight;
 102
 103                                 /* Create resources */
 104                                 long hdc = OS.GetDC (0);
 105                                 long srcHdc = OS.CreateCompatibleDC (hdc);
 106                                 long oldSrcBitmap = OS.SelectObject (srcHdc, hImage);
 107                                 long memHdc = OS.CreateCompatibleDC (hdc);
 108                                 BITMAPINFOHEADER bmiHeader = new BITMAPINFOHEADER ();
 109                                 bmiHeader.biSize = BITMAPINFOHEADER.sizeof;
 110                                 bmiHeader.biWidth = srcWidth;
 111                                 bmiHeader.biHeight = -srcHeight;
 112                                 bmiHeader.biPlanes = 1;
 113                                 bmiHeader.biBitCount = 32;
 114                                 bmiHeader.biCompression = OS.BI_RGB;
 115                                 byte [] bmi = new byte[BITMAPINFOHEADER.sizeof];
 116                                 OS.MoveMemory (bmi, bmiHeader, BITMAPINFOHEADER.sizeof);
 117                                 long [] pBits = new long [1];
 118                                 long memDib = OS.CreateDIBSection (0, bmi, OS.DIB_RGB_COLORS, pBits, 0, 0);
 119                                 if (memDib == 0) SWT.error (SWT.ERROR_NO_HANDLES);
 120                                 long oldMemBitmap = OS.SelectObject (memHdc, memDib);
 121
 122                                 BITMAP dibBM = new BITMAP ();
 123                                 OS.GetObject (memDib, BITMAP.sizeof, dibBM);
 124                                 int sizeInBytes = dibBM.bmWidthBytes * dibBM.bmHeight;
 125
 126                                 /* Get the foreground pixels */
 127                                 OS.BitBlt (memHdc, 0, 0, srcWidth, srcHeight, srcHdc, 0, 0, OS.SRCCOPY);
 128                                 byte[] srcData = new byte [sizeInBytes];
 129                                 OS.MoveMemory (srcData, dibBM.bmBits, sizeInBytes);
 130
 131                                 PaletteData palette = new PaletteData(0xFF00, 0xFF0000, 0xFF000000);
 132                                 ImageData data = new ImageData(srcWidth, srcHeight, bm.bmBitsPixel, palette, bm.bmWidthBytes, srcData);
 133                                 if (shdi.crColorKey == -1) {
 134                                         byte[] alphaData = new byte[srcWidth * srcHeight];
 135                                         int spinc = dibBM.bmWidthBytes - srcWidth * 4;
 136                                         int ap = 0, sp = 3;
 137                                         for (int y = 0; y < srcHeight; ++y) {
 138                                                 for (int x = 0; x < srcWidth; ++x) {
 139                                                         alphaData [ap++] = srcData [sp];
 140                                                         sp += 4;
 141                                                 }
 142                                                 sp += spinc;
 143                                         }
 144                                         data.alphaData = alphaData;
 145                                 } else {
 146                                         data.transparentPixel = shdi.crColorKey << 8;
 147                                 }
 148                                 Display display = control.getDisplay ();
 149                                 dragSourceImage = new Image (display, new AutoScaleImageDataProvider(display, data, DPIUtil.getDeviceZoom()));
 150                                 OS.SelectObject (memHdc, oldMemBitmap);
 151                                 OS.DeleteDC (memHdc);
 152                                 OS.DeleteObject (memDib);
 153                                 OS.SelectObject (srcHdc, oldSrcBitmap);
 154                                 OS.DeleteDC (srcHdc);
 155                                 OS.ReleaseDC (0, hdc);
 156                                 OS.DeleteObject (hImage);
 157                                 return dragSourceImage;
 158                         }
 159                 }
 160                 return null;
 161         }
 162 }