TableDragSourceEffect.java :  » IDE-Eclipse » swt » org » eclipse » swt » dnd » Java Open Source

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/*******************************************************************************
 * Copyright (c) 2007, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.dnd;

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.internal.win32.*;
import org.eclipse.swt.widgets.*;

/**
 * This class provides default implementations to display a source image
 * when a drag is initiated from a <code>Table</code>.
 * 
 * <p>Classes that wish to provide their own source image for a <code>Table</code> can
 * extend the <code>TableDragSourceEffect</code> class, override the 
 * <code>TableDragSourceEffect.dragStart</code> method and set the field 
 * <code>DragSourceEvent.image</code> with their own image.</p>
 *
 * Subclasses that override any methods of this class must call the corresponding
 * <code>super</code> method to get the default drag source effect implementation.
 *
 * @see DragSourceEffect
 * @see DragSourceEvent
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 * 
 * @since 3.3
 */
public class TableDragSourceEffect extends DragSourceEffect {
  Image dragSourceImage = null;
  
  /**
   * Creates a new <code>TableDragSourceEffect</code> to handle drag effect 
   * from the specified <code>Table</code>.
   *
   * @param table the <code>Table</code> that the user clicks on to initiate the drag
   */
  public TableDragSourceEffect(Table table) {
    super(table);
  }

  /**
   * This implementation of <code>dragFinished</code> disposes the image
   * that was created in <code>TableDragSourceEffect.dragStart</code>.
   * 
   * Subclasses that override this method should call <code>super.dragFinished(event)</code>
   * to dispose the image in the default implementation.
   * 
   * @param event the information associated with the drag finished event
   */
  public void dragFinished(DragSourceEvent event) {
    if (dragSourceImage != null) dragSourceImage.dispose();
    dragSourceImage = null;    
  }
  
  /**
   * This implementation of <code>dragStart</code> will create a default
   * image that will be used during the drag. The image should be disposed
   * when the drag is completed in the <code>TableDragSourceEffect.dragFinished</code>
   * method.
   * 
   * Subclasses that override this method should call <code>super.dragStart(event)</code>
   * to use the image from the default implementation.
   * 
   * @param event the information associated with the drag start event
   */
  public void dragStart(DragSourceEvent event) {
    event.image = getDragSourceImage(event);
  }
  
  Image getDragSourceImage(DragSourceEvent event) {
    if (dragSourceImage != null) dragSourceImage.dispose();
    dragSourceImage = null;
    if (!OS.IsWinCE && OS.WIN32_VERSION >= OS.VERSION (5, 1)) {
      SHDRAGIMAGE shdi = new SHDRAGIMAGE();
      int DI_GETDRAGIMAGE = OS.RegisterWindowMessage (new TCHAR (0, "ShellGetDragImage", true)); //$NON-NLS-1$
      if (OS.SendMessage (control.handle, DI_GETDRAGIMAGE, 0, shdi) != 0) {
        if ((control.getStyle() & SWT.MIRRORED) != 0) {
          event.offsetX = shdi.sizeDragImage.cx - shdi.ptOffset.x;
        } else {
          event.offsetX = shdi.ptOffset.x;
        }
        event.offsetY = shdi.ptOffset.y;
        int /*long*/ hImage = shdi.hbmpDragImage;
        if (hImage != 0) {
          BITMAP bm = new BITMAP ();
          OS.GetObject (hImage, BITMAP.sizeof, bm);
          int srcWidth = bm.bmWidth;
          int srcHeight = bm.bmHeight;
          
          /* Create resources */
          int /*long*/ hdc = OS.GetDC (0);
          int /*long*/ srcHdc = OS.CreateCompatibleDC (hdc);
          int /*long*/ oldSrcBitmap = OS.SelectObject (srcHdc, hImage);
          int /*long*/ memHdc = OS.CreateCompatibleDC (hdc);
          BITMAPINFOHEADER bmiHeader = new BITMAPINFOHEADER ();
          bmiHeader.biSize = BITMAPINFOHEADER.sizeof;
          bmiHeader.biWidth = srcWidth;
          bmiHeader.biHeight = -srcHeight;
          bmiHeader.biPlanes = 1;
          bmiHeader.biBitCount = 32;
          bmiHeader.biCompression = OS.BI_RGB;
          byte []  bmi = new byte[BITMAPINFOHEADER.sizeof];
          OS.MoveMemory (bmi, bmiHeader, BITMAPINFOHEADER.sizeof);
          int /*long*/ [] pBits = new int /*long*/ [1];
          int /*long*/ memDib = OS.CreateDIBSection (0, bmi, OS.DIB_RGB_COLORS, pBits, 0, 0);
          if (memDib == 0) SWT.error (SWT.ERROR_NO_HANDLES);
          int /*long*/ oldMemBitmap = OS.SelectObject (memHdc, memDib);

          BITMAP dibBM = new BITMAP ();
          OS.GetObject (memDib, BITMAP.sizeof, dibBM);
          int sizeInBytes = dibBM.bmWidthBytes * dibBM.bmHeight;

           /* Get the foreground pixels */
           OS.BitBlt (memHdc, 0, 0, srcWidth, srcHeight, srcHdc, 0, 0, OS.SRCCOPY);
           byte[] srcData = new byte [sizeInBytes];
          OS.MoveMemory (srcData, dibBM.bmBits, sizeInBytes);

          PaletteData palette = new PaletteData(0xFF00, 0xFF0000, 0xFF000000);
          ImageData data = new ImageData(srcWidth, srcHeight, bm.bmBitsPixel, palette, bm.bmWidthBytes, srcData);
          if (shdi.crColorKey == -1) {
            byte[] alphaData = new byte[srcWidth * srcHeight];
            int spinc = dibBM.bmWidthBytes - srcWidth * 4;
            int ap = 0, sp = 3;
            for (int y = 0; y < srcHeight; ++y) {
              for (int x = 0; x < srcWidth; ++x) {
                alphaData [ap++] = srcData [sp];
                sp += 4;
              }
              sp += spinc;
            }
            data.alphaData = alphaData;
          } else {
            data.transparentPixel = shdi.crColorKey << 8;
          }
          dragSourceImage = new Image(control.getDisplay(), data);
          OS.SelectObject (memHdc, oldMemBitmap);
          OS.DeleteDC (memHdc);
          OS.DeleteObject (memDib);
          OS.SelectObject (srcHdc, oldSrcBitmap);
          OS.DeleteDC (srcHdc);
          OS.ReleaseDC (0, hdc);
          OS.DeleteObject (hImage);
          return dragSourceImage;
        }
      }
      return null;
    }
    Table table = (Table) control;
    //TEMPORARY CODE
    if (table.isListening (SWT.EraseItem) || table.isListening (SWT.PaintItem)) return null;
    TableItem[] selection = table.getSelection();
    if (selection.length == 0) return null;
    int /*long*/ tableImageList = OS.SendMessage (table.handle, OS.LVM_GETIMAGELIST, OS.LVSIL_SMALL, 0);
    if (tableImageList != 0) {
      int count = Math.min(selection.length, 10);
      Rectangle bounds = selection[0].getBounds(0);
      for (int i = 1; i < count; i++) {
        bounds = bounds.union(selection[i].getBounds(0));
      }
      int /*long*/ hDC = OS.GetDC(0);
      int /*long*/ hDC1 = OS.CreateCompatibleDC(hDC);
      if (!OS.IsWinCE && OS.WIN32_VERSION >= OS.VERSION(4, 10)) {
        if ((table.getStyle() & SWT.RIGHT_TO_LEFT) != 0) {
          OS.SetLayout(hDC1, OS.LAYOUT_RTL | OS.LAYOUT_BITMAPORIENTATIONPRESERVED);
        }
      }
      int /*long*/ bitmap = OS.CreateCompatibleBitmap(hDC, bounds.width, bounds.height);
      int /*long*/ hOldBitmap = OS.SelectObject(hDC1, bitmap);
      RECT rect = new RECT();
      rect.right = bounds.width;
      rect.bottom = bounds.height;
      int /*long*/ hBrush = OS.GetStockObject(OS.WHITE_BRUSH);
      OS.FillRect(hDC1, rect, hBrush);
      for (int i = 0; i < count; i++) {
        TableItem selected = selection[i];
        Rectangle cell = selected.getBounds(0);
        POINT pt = new POINT();
        int /*long*/ imageList = OS.SendMessage (table.handle, OS.LVM_CREATEDRAGIMAGE, table.indexOf(selected), pt);
        OS.ImageList_Draw(imageList, 0, hDC1, cell.x - bounds.x, cell.y - bounds.y, OS.ILD_SELECTED);
        OS.ImageList_Destroy(imageList);
      }
      OS.SelectObject(hDC1, hOldBitmap);
      OS.DeleteDC (hDC1);
      OS.ReleaseDC (0, hDC);
      Display display = table.getDisplay();
      dragSourceImage = Image.win32_new(display, SWT.BITMAP, bitmap);
      return dragSourceImage;
    }
    return null;
  }
}
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