bundles/org.eclipse.swt.win32.win32.x86_64/src/org/eclipse/swt/dnd/TableDragSourceEffect.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>Table</code>.
  26  *
  27  * <p>Classes that wish to provide their own source image for a <code>Table</code> can
  28  * extend the <code>TableDragSourceEffect</code> class, override the
  29  * <code>TableDragSourceEffect.dragStart</code> method and set the field
  30  * <code>DragSourceEvent.image</code> with their own image.</p>
  31  *
  32  * Subclasses that override any methods of this class must call the corresponding
  33  * <code>super</code> method to get the default drag source effect implementation.
  34  *
  35  * @see DragSourceEffect
  36  * @see DragSourceEvent
  37  * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
  38  *
  39  * @since 3.3
  40  */
  41 public class TableDragSourceEffect extends DragSourceEffect {
  42         Image dragSourceImage = null;
  43
  44         /**
  45          * Creates a new <code>TableDragSourceEffect</code> to handle drag effect
  46          * from the specified <code>Table</code>.
  47          *
  48          * @param table the <code>Table</code> that the user clicks on to initiate the drag
  49          */
  50         public TableDragSourceEffect(Table table) {
  51                 super(table);
  52         }
  53
  54         /**
  55          * This implementation of <code>dragFinished</code> disposes the image
  56          * that was created in <code>TableDragSourceEffect.dragStart</code>.
  57          *
  58          * Subclasses that override this method should call <code>super.dragFinished(event)</code>
  59          * to dispose the image in the default implementation.
  60          *
  61          * @param event the information associated with the drag finished event
  62          */
  63         @Override
  64         public void dragFinished(DragSourceEvent event) {
  65                 if (dragSourceImage != null) dragSourceImage.dispose();
  66                 dragSourceImage = null;
  67         }
  68
  69         /**
  70          * This implementation of <code>dragStart</code> will create a default
  71          * image that will be used during the drag. The image should be disposed
  72          * when the drag is completed in the <code>TableDragSourceEffect.dragFinished</code>
  73          * method.
  74          *
  75          * Subclasses that override this method should call <code>super.dragStart(event)</code>
  76          * to use the image from the default implementation.
  77          *
  78          * @param event the information associated with the drag start event
  79          */
  80         @Override
  81         public void dragStart(DragSourceEvent event) {
  82                 event.image = getDragSourceImage(event);
  83         }
  84
  85         Image getDragSourceImage(DragSourceEvent event) {
  86                 if (dragSourceImage != null) dragSourceImage.dispose();
  87                 dragSourceImage = null;
  88                 SHDRAGIMAGE shdi = new SHDRAGIMAGE();
  89                 int DI_GETDRAGIMAGE = OS.RegisterWindowMessage (new TCHAR (0, "ShellGetDragImage", true)); //$NON-NLS-1$
  90                 if (OS.SendMessage (control.handle, DI_GETDRAGIMAGE, 0, shdi) != 0) {
  91                         if ((control.getStyle() & SWT.MIRRORED) != 0) {
  92                                 event.offsetX = shdi.sizeDragImage.cx - shdi.ptOffset.x;
  93                         } else {
  94                                 event.offsetX = shdi.ptOffset.x;
  95                         }
  96                         event.offsetY = shdi.ptOffset.y;
  97                         long hImage = shdi.hbmpDragImage;
  98                         if (hImage != 0) {
  99                                 BITMAP bm = new BITMAP ();
 100                                 OS.GetObject (hImage, BITMAP.sizeof, bm);
 101                                 int srcWidth = bm.bmWidth;
 102                                 int srcHeight = bm.bmHeight;
 103
 104                                 /* Create resources */
 105                                 long hdc = OS.GetDC (0);
 106                                 long srcHdc = OS.CreateCompatibleDC (hdc);
 107                                 long oldSrcBitmap = OS.SelectObject (srcHdc, hImage);
 108                                 long memHdc = OS.CreateCompatibleDC (hdc);
 109                                 BITMAPINFOHEADER bmiHeader = new BITMAPINFOHEADER ();
 110                                 bmiHeader.biSize = BITMAPINFOHEADER.sizeof;
 111                                 bmiHeader.biWidth = srcWidth;
 112                                 bmiHeader.biHeight = -srcHeight;
 113                                 bmiHeader.biPlanes = 1;
 114                                 bmiHeader.biBitCount = 32;
 115                                 bmiHeader.biCompression = OS.BI_RGB;
 116                                 byte [] bmi = new byte[BITMAPINFOHEADER.sizeof];
 117                                 OS.MoveMemory (bmi, bmiHeader, BITMAPINFOHEADER.sizeof);
 118                                 long [] pBits = new long [1];
 119                                 long memDib = OS.CreateDIBSection (0, bmi, OS.DIB_RGB_COLORS, pBits, 0, 0);
 120                                 if (memDib == 0) SWT.error (SWT.ERROR_NO_HANDLES);
 121                                 long oldMemBitmap = OS.SelectObject (memHdc, memDib);
 122
 123                                 BITMAP dibBM = new BITMAP ();
 124                                 OS.GetObject (memDib, BITMAP.sizeof, dibBM);
 125                                 int sizeInBytes = dibBM.bmWidthBytes * dibBM.bmHeight;
 126
 127                                 /* Get the foreground pixels */
 128                                 OS.BitBlt (memHdc, 0, 0, srcWidth, srcHeight, srcHdc, 0, 0, OS.SRCCOPY);
 129                                 byte[] srcData = new byte [sizeInBytes];
 130                                 OS.MoveMemory (srcData, dibBM.bmBits, sizeInBytes);
 131
 132                                 PaletteData palette = new PaletteData(0xFF00, 0xFF0000, 0xFF000000);
 133                                 ImageData data = new ImageData(srcWidth, srcHeight, bm.bmBitsPixel, palette, bm.bmWidthBytes, srcData);
 134                                 if (shdi.crColorKey == -1) {
 135                                         byte[] alphaData = new byte[srcWidth * srcHeight];
 136                                         int spinc = dibBM.bmWidthBytes - srcWidth * 4;
 137                                         int ap = 0, sp = 3;
 138                                         for (int y = 0; y < srcHeight; ++y) {
 139                                                 for (int x = 0; x < srcWidth; ++x) {
 140                                                         alphaData [ap++] = srcData [sp];
 141                                                         sp += 4;
 142                                                 }
 143                                                 sp += spinc;
 144                                         }
 145                                         data.alphaData = alphaData;
 146                                 } else {
 147                                         data.transparentPixel = shdi.crColorKey << 8;
 148                                 }
 149                                 Display display = control.getDisplay();
 150                                 dragSourceImage = new Image(display, new AutoScaleImageDataProvider(display, data, DPIUtil.getDeviceZoom()));
 151                                 OS.SelectObject (memHdc, oldMemBitmap);
 152                                 OS.DeleteDC (memHdc);
 153                                 OS.DeleteObject (memDib);
 154                                 OS.SelectObject (srcHdc, oldSrcBitmap);
 155                                 OS.DeleteDC (srcHdc);
 156                                 OS.ReleaseDC (0, hdc);
 157                                 OS.DeleteObject (hImage);
 158                                 return dragSourceImage;
 159                         }
 160                 }
 161                 return null;
 162         }
 163 }