在创建椭圆并将其位置存储在画布上之后,我正在尝试在画布上创建两个椭圆之间的连接。需要使用这些存储的位置来创建连接。我编写的代码适用于矩形图形,但不适用于椭圆。我似乎看不出这两种情况之间的区别。有人能帮忙吗?谢谢。*我添加了简短的可测试代码来说明我的问题。要查看它在Rectangle中的工作情况,请取消注释行“uncomment THIS”
import java.util.ArrayList;
import org.eclipse.draw2d.ColorConstants;
import org.eclipse.draw2d.ChopboxAnchor;
import org.eclipse.draw2d.Ellipse;
import org.eclipse.draw2d.Figure;
import org.eclipse.draw2d.IFigure;
import org.eclipse.draw2d.LightweightSystem;
import org.eclipse.draw2d.PolygonDecoration;
import org.eclipse.draw2d.PolylineConnection;
import org.eclipse.draw2d.RectangleFigure;
import org.eclipse.draw2d.geometry.Point;
import org.eclipse.draw2d.geometry.Rectangle;
import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DragSourceEvent;
import org.eclipse.swt.dnd.DragSourceListener;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.dnd.DropTargetEvent;
import org.eclipse.swt.dnd.DropTargetListener;
import org.eclipse.swt.dnd.TextTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Layout;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Group;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Label;
public class EllipseProblem
{
private Shell shell;
private Display display;
private final Label lblUnicorn;
private final Canvas canvas;
final IFigure panel;
public static ArrayList canvasElements= new ArrayList();
public static void main(String args[])
{
new EllipseProblem();
}
public EllipseProblem()
{
display = new Display();
shell = new Shell(display);
shell.setText("SWT Application");
shell.setLayout(new GridLayout(2, false));
Group grpPalette = new Group(shell, SWT.NONE);
grpPalette.setText("Palette");
grpPalette.setLayout(new GridLayout());
grpPalette.setLayoutData(new GridData(SWT.BEGINNING, SWT.FILL, false, true));
lblUnicorn = new Label(grpPalette, SWT.BORDER | SWT.HORIZONTAL | SWT.CENTER);
lblUnicorn.setText("UNICORN");
lblUnicorn.setAlignment(SWT.CENTER);
final Group grpCanvas = new Group(shell, SWT.NONE);
grpCanvas.setText("Canvas");
grpCanvas.setLayout(new GridLayout());
grpCanvas.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
canvas = new Canvas(grpCanvas, SWT.NONE);
canvas.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
Button btnCreate = new Button(grpPalette, SWT.CENTER);
GridData gd_btnCreate = new GridData(SWT.LEFT, SWT.CENTER, false, false, 1, 1);
gd_btnCreate.widthHint = 87;
gd_btnCreate.heightHint = 33;
btnCreate.setLayoutData(gd_btnCreate);
btnCreate.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent e) {
drawConnection();
}
});
btnCreate.setText("Make Connection");
LightweightSystem lws = new LightweightSystem(canvas);
panel = new Figure();
lws.setContents(panel);
DragSource dragSource1 = new DragSource(lblUnicorn, DND.DROP_COPY);
Transfer[] transfers1 = new Transfer[] { TextTransfer.getInstance() };
dragSource1.setTransfer(transfers1);
dragSource1.addDragListener(new DragSourceListener()
{
public void dragStart(DragSourceEvent event)
{
if (lblUnicorn.getText().length() == 0)
{
event.doit = false;
}
}
public void dragSetData(DragSourceEvent event)
{
if (TextTransfer.getInstance().isSupportedType(event.dataType))
{
event.data = lblUnicorn.getText();
}
}
public void dragFinished(DragSourceEvent event)
{
}
});
Transfer[] types = new Transfer[] { TextTransfer.getInstance() };
DropTarget dropTarget = new DropTarget(canvas, DND.DROP_COPY | DND.DROP_DEFAULT);
dropTarget.setTransfer(types);
dropTarget.addDropListener(new DropTargetListener()
{
public void dragEnter(DropTargetEvent event)
{
if (event.detail == DND.DROP_DEFAULT)
{
if ((event.operations & DND.DROP_COPY) != 0)
{
event.detail = DND.DROP_COPY;
}
else
{
event.detail = DND.DROP_NONE;
}
}
}
public void dragLeave(DropTargetEvent event)
{
}
public void dragOperationChanged(DropTargetEvent event)
{
}
public void dragOver(DropTargetEvent event)
{
}
public void drop(DropTargetEvent event)
{
}
public void dropAccept(final DropTargetEvent event)
{
if (TextTransfer.getInstance().isSupportedType(event.currentDataType))
{
String d = (String) TextTransfer.getInstance().nativeToJava(event.currentDataType);
final String finald= d;
org.eclipse.swt.graphics.Point droppoint = canvas.toControl(event.x, event.y);
canvasElements.add(droppoint);
Rectangle rect=new Rectangle(droppoint.x, droppoint.y, 40, 20);
Rectangle rect2=new Rectangle(droppoint.x+20, droppoint.y, 100, 25);
Ellipse node= new Ellipse();
node.setBounds(rect);
System.out.println(node.getBounds());
node.setLocation(new Point(droppoint.x, droppoint.y));
node.setBackgroundColor(ColorConstants.red);
panel.add(node);
org.eclipse.draw2d.Label droppedName=
new org.eclipse.draw2d.Label(finald);
droppedName.setLocation(new Point(droppoint.x, droppoint.y));
droppedName.setBounds(rect2);
panel.add(node);
panel.add(droppedName);
canvas.redraw();
}
}
});
shell.pack();
shell.setSize(400, 300);
shell.open();
while (!shell.isDisposed())
{
if (!display.readAndDispatch())
{
display.sleep();
}
}
}
protected void drawConnection()
{
org.eclipse.swt.graphics.Point swt_origin= (org.eclipse.swt.graphics.Point) canvasElements.get(0);
org.eclipse.draw2d.geometry.Point origin_point= new org.eclipse.draw2d.geometry.Point(swt_origin.x, swt_origin.y);
org.eclipse.swt.graphics.Point swt_destination= (org.eclipse.swt.graphics.Point) canvasElements.get(1);
org.eclipse.draw2d.geometry.Point destination_point= new org.eclipse.draw2d.geometry.Point(swt_destination.x, swt_destination.y);
IFigure origin = panel.findFigureAt(origin_point);
IFigure destination = panel.findFigureAt(destination_point);
PolylineConnection conn = new PolylineConnection();
conn.setSourceAnchor(new ChopboxAnchor(origin));
conn.setTargetAnchor(new ChopboxAnchor(destination));
conn.setTargetDecoration(new PolygonDecoration());
panel.add(conn);
}
}
