月蚀：表列图像透明与否？

Question

在我开始绘制自己的图片在Eclipse表格单元格，突出在一个陌生的高亮颜色的表格单元格的结果。看到自己：

虽然透明性实际上是像保存在第一列中，高亮蓝并不如它应该为蓝色。这是我的错或者Eclipse的错吗？

下面的代码片断：

public class TransparentOrNot {

  public static void main(String[] args) {
    Display firstDisplay = new Display();
    Shell firstShell = new Shell(firstDisplay);
    firstShell.setText("Transparent-or-not!");
    firstShell.setSize(300, 200);
    firstShell.setLayout(new FillLayout());

    TableViewer viewer = new TableViewer(firstShell, SWT.MULTI);
    viewer.getTable().setLinesVisible(true);
    viewer.getTable().setHeaderVisible(true);

    TableViewerColumn tableViewerColumn = new TableViewerColumn(viewer, SWT.CENTER);
    tableViewerColumn.getColumn().setText("First");
    tableViewerColumn.getColumn().setWidth(150);
    tableViewerColumn.setLabelProvider(new ColumnLabelProvider() {

      @Override
      public Image getImage(Object element) {
        return ImageDescriptor.createFromFile(TransparentOrNot.class, "/red.png").createImage();
      }

      @Override
      public String getText(Object element) {
        return null;
      }
    });
    tableViewerColumn = new TableViewerColumn(viewer, SWT.CENTER);
    tableViewerColumn.getColumn().setText("Second");
    tableViewerColumn.getColumn().setWidth(150);
    tableViewerColumn.setLabelProvider(new CenterImageLabelProvider());
    viewer.setContentProvider(ArrayContentProvider.getInstance());

    viewer.setInput(new String[][]{{"a", "b"}, {"c", "d"}});

    firstShell.open();
    while (!firstShell.isDisposed()) {
      if (!firstDisplay.readAndDispatch()) {
        firstDisplay.sleep();
      }
    }
    firstDisplay.dispose();
  }

  static class CenterImageLabelProvider extends OwnerDrawLabelProvider {

    @Override
    protected void measure(Event event, Object element) {
      // no-op
    }

    @Override
    protected void paint(Event event, Object element) {

      Image image = ImageDescriptor.createFromFile(TransparentOrNot.class, "/green.png").createImage();

      Widget item = event.item;
      Rectangle bounds = ((TableItem) item).getBounds(event.index);

      Rectangle imgBounds = image.getBounds();
      bounds.width /= 2;
      bounds.width -= imgBounds.width / 2;
      bounds.height /= 2;
      bounds.height -= imgBounds.height / 2;

      int x = bounds.width > 0 ? bounds.x + bounds.width : bounds.x;
      int y = bounds.height > 0 ? bounds.y + bounds.height : bounds.y;

      event.gc.drawImage(image, x, y);
    }
  }
}

Answer 1

重写擦除（）和不的调用super.erase（）的帮助。