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Creating links via dragging from anchors [message #146308]

Tue, 03 August 2004 12:16

Eclipse User

Originally posted by: rsudra.hotmail.com

Dear all,

I was hoping to get some information/direction regarding creating links
between components by dragging from the sources components anchor to the
target components anchor. I am currently using Gef 2.1.2 and it is
unlikely for the moment that we will be upgrading.

Many thanks,
Raj

Re: Creating links via dragging from anchors [message #146317 is a reply to message #146308]

Tue, 03 August 2004 13:19

Eclipse User

Originally posted by: none.us.ibm.com

Create a handle and place it on the handle layer. have the handle return
the ConnectionDragCreationTool.

"Rajeev Sudra" <rsudra@hotmail.com> wrote in message
news:ceodpa$5v7$1@eclipse.org...
> Dear all,
>
> I was hoping to get some information/direction regarding creating links
> between components by dragging from the sources components anchor to the
> target components anchor. I am currently using Gef 2.1.2 and it is
> unlikely for the moment that we will be upgrading.
>
> Many thanks,
> Raj
>

Re: Creating links via dragging from anchors [message #146440 is a reply to message #146317]

Wed, 04 August 2004 06:54

Eclipse User

Originally posted by: rsudra.hotmail.com

I create my on handle as:

Handle dragLinkCreationHandle = new SquareHandle() {
protected DragTracker createDragTracker() {
return new ConnectionDragCreationTool();
}
};

in the edit parts constructor but how do I I add it to the edit parts
handle layer. Calling getLayer(...) in the constructor throws an NPE (prob
because the layers are initialised later).

On my editpart (representing a component, not a connection) where do I add
the handle? Is there a way of giving the handle visual selection feedback?

Not sure if it is relevant but my editpart returns an input and output
ConnectionAnchor, perhaps there is a way of adding the handle to that
along with the visual feedback?

Randy Hudson wrote:

> Create a handle and place it on the handle layer. have the handle return
> the ConnectionDragCreationTool.

Re: Creating links via dragging from anchors [message #146452 is a reply to message #146440]

Wed, 04 August 2004 07:56

Eclipse User

Originally posted by: eostroukhov.hotmail.com

Look at ResizableEditPolicy::createSelectionHandles - there's handle
creation code there.

"Rajeev Sudra" <rsudra@hotmail.com> wrote in message
news:ceqf9m$5dv$1@eclipse.org...
> I create my on handle as:
>
> Handle dragLinkCreationHandle = new SquareHandle() {
> protected DragTracker createDragTracker() {
> return new ConnectionDragCreationTool();
> }
> };
>
> in the edit parts constructor but how do I I add it to the edit parts
> handle layer. Calling getLayer(...) in the constructor throws an NPE (prob
> because the layers are initialised later).
>
> On my editpart (representing a component, not a connection) where do I add
> the handle? Is there a way of giving the handle visual selection feedback?
>
> Not sure if it is relevant but my editpart returns an input and output
> ConnectionAnchor, perhaps there is a way of adding the handle to that
> along with the visual feedback?
>
>
> Randy Hudson wrote:
>
> > Create a handle and place it on the handle layer. have the handle
return
> > the ConnectionDragCreationTool.
>
>
>

Re: Creating links via dragging from anchors [message #146459 is a reply to message #146452]

Wed, 04 August 2004 10:33

Eclipse User

Originally posted by: rsudra.hotmail.com

Thanks Eugene,

i have created my own subtype of NonResizableEditPolicy:

public class DragLinkCreationNonResizableEditPolicy extends
NonResizableEditPolicy {

private final GraphicalEditPart graphicalEditPart;

public DragLinkCreationNonResizableEditPolicy(GraphicalEditPart child)
{
graphicalEditPart = child;
}

protected List createSelectionHandles() {
SquareHandle handle = new SquareHandle(graphicalEditPart,
new RelativeHandleLocator(graphicalEditPart.getFigure(),
PositionConstants.EAST)) {

protected DragTracker createDragTracker() {
return new ConnectionDragCreationTool();
}
};
List selectionHandles = super.createSelectionHandles();
selectionHandles.add(handle);
return selectionHandles;
}

}

I then override XYLayoutEditPolicy.createChildEditPolicy(..) returning the
above edit policy.

It seems to work, but I know want to show feedback when hovering over the
handle that allows creation of links. Would I need to register another
edit policy on my base ComponentGraphEditParts SELECTION_FEEDBACK_ROLE?
Which policy would I subtype?

Is there an alternate way of providing this type of feedback, such as
direct on the GraphEditPart?

TIA,
Raj

---
Eugene Ostroukhov wrote:

> Look at ResizableEditPolicy::createSelectionHandles - there's handle
> creation code there.

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