[GEF] EditPolicy - LAYOUT_ROLE & PRIMARY_DRAG_ROLE

일반적으로 GEF 에서 EditPart 에 EditPolicy.LAYOUT_ROLE 로 editpolicy 를 install 하게 됩니다. public class XxxxPart extends AbstractGraphicalEditPart implements PropertyChangeListener { @Override protected void createEditPolicies() { installEditPolicy(EditPolicy.LAYOUT_ROLE, new XxxxEditLayoutPolicy()); } ... }


이렇게 처리할 경우 생성이나 이동, 리사이징에는 별 무리 없이 사용할 수 있을 것이라 생각하였으나 한가지 문제가 있었습니다. 다른 자식 피규어와 겹칠경우 정상적으로 이동이 되지 않는 것이었습니다. LAYOUT_ROLE 로는 다른 자식 피규어 위에서 이동하는 것에 대한 이벤트를 잡지 않는 것으로 파악이 되었습니다. 그래서 조금 찾아보니 될 것만 같은 것이 있어서 한번 수정한 후 실행을 해보았습니다.
public class XxxxPart extends AbstractGraphicalEditPart implements PropertyChangeListener { @Override protected void createEditPolicies() { // EditPolicy 를 PRIMARY_DRAG_ROLE 로 교체 // installEditPolicy(EditPolicy.LAYOUT_ROLE, new XxxxEditLayoutPolicy()); installEditPolicy(EditPolicy.PRIMARY_DRAG_ROLE, new XxxxEditLayoutPolicy()); } ... }


그냥 한번 해보았을 뿐인데... 원하는 결과가 나와버렸습니다. 그래서 구글에서 좀 찾아보니 아래와 같은 자료가 있었습니다.

Because of the relationship between handles and layouts, it is recommended that the PRIMARY_DRAG_ROLE editpolicy be installed by the parent's LayoutEditPolicy, which defines abstract methods for this purpose. If a container changes layout managers during editing, typically the layout policy gets swapped with one for the new layout manager. The new policy then replaces the stalePRIMARY_DRAG_ROLE policies on each child.

무신 말씀을 하시는지는 정확하게 파악을 하지 못하였으나 잘 돌아가주시니 감사할 따름입니다.

출처: http://help.eclipse.org/stable/index.jsp?topic=/org.eclipse.gef.doc.isv/guide/guide.html

Moving and Resizing

Tools	Requests	Edit Policies and Roles	Actions
DragEditPartsTracker ResizeTracker	ChangeBoundsRequest AlignmentRequest REQ_MOVE REQ_ADD REQ_ORPHAN   REQ_CLONE REQ_ALIGN REQ_RESIZE	LayoutEditPolicy ResizableEditPolicy ContainerEditPolicy	AlignmentAction MatchSizeAction

move interaction

resize interaction

The DragEditPartsTracker extends basic selection behavior to allow the selected parts to be dragged within their graphical viewer. Dragging the selected parts can result in three potential interactions: move, reparent, and clone. All three use theChangeBoundsRequest, which extends GroupRequest to include a size delta, move delta, and mouse location.

While dragging the selection, if the tracker targets the part's original parent, the request is typed as REQ_MOVE. If the target changes, the interaction becomes a reparent. For a reparent, a request of type REQ_ORPHAN is sent to the old parent, while the new target is sent a request of type REQ_ADD. When the CTRL key is pressed (ALT on the Mac), the operation is always a REQ_CLONE, which is only sent to the target part.

All of these requests are related in that they require the target to process a rectangle and a mouse location. The LayoutEditPolicy is responsible for handling each of these request types. For layouts which use constraints, each part's original bounds is taken and modified by the size and move deltas to determine a new bounds, for which a corresponding constraint is found. For index-based layouts, the mouse location is used to establish the new index.

A ContainerEditPolicy can optionally be used to contribute additional commands (not related to the layout) during ADD, ORPHAN, and CLONE requests.

Resizing

Resizing falls under the same category as changing bounds. Note that when resizing either the top or left sides, the location of the part is also changed. Resizing only makes sense for layouts with constraints, such as XYLayout. The ResizableEditPolicy adds up to eight resize handles to its host. When the Selection Tool is clicked on one of these resize handles, a ResizeTracker performs a resize on the selected parts understanding "resize". SHIFT and CTRL key modifiers can be used to constrain the resize operation.

The types of handles available on an editpart depend on the layout manager in which its figure is placed. For example, parts inside a table might have handles for adjusting insets, padding, column span, or other attributes. Some layouts don't need any handles, but four corner handles should be added just to indicate selection. Dragging these handles would be the same as dragging the part itself.

Because of the relationship between handles and layouts, it is recommended that the PRIMARY_DRAG_ROLE editpolicy be installed by the parent's LayoutEditPolicy, which defines abstract methods for this purpose. If a container changes layout managers during editing, typically the layout policy gets swapped with one for the new layout manager. The new policy then replaces the stalePRIMARY_DRAG_ROLE policies on each child.

The MatchSizeAction matches the size of the selected parts to that of the primary selected part's size. This action is implemented in a way similar to manually resizing the individual parts, and it uses the same request and type.

The AlignmentAction uses an AlignmentRequest, which extends ChangeBoundsRequest. When using a ChangeBoundsRequest, the part's current placement in the Control (in absolute coordinates) is passed to the request, which then returns a modified version. Using this pattern, alignment is able to adjust each part's rectangle by different amounts. In most cases, alignment can be treated no differently than a move. This action aligns all selected parts with one of the edges of the primary selected part.

뭐 해결했다는게 중요한게 아닙니까 하하하하;;;;