#referencePostion returns the specified center for the morph in global coordinates.

By default this will be the same as ���self bounds origin + (self bounds extent/2.0)��� but can have other depending on what #rotationCenter returns.

#referencePositon: on the other hand do not set a new centre, but moves the morph to a new position by using the referencePosition as origin instead of its top left corner.

Example:

| m |

m := Morph new

               color: Color orange;

               extent: 200@72;

               openCenteredInWorld;

               yourself.

m on: #click send: #value to: [ m referencePosition: (m referencePosition + (10@10)) ]   .

Looking at Morph>>#handleDropMorph: referencePosition is used to place the dropped morph in centre of the new owner.

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observation:

���(self transformedFrom: anEvent hand world) globalPointToLocal: aMorph referencePosition��� looks incomplete as it will always be equal to just doing ���aMorph referencePosition��� because #transformedFrom: always returns an IdentityTransform where # globalPointToLocal: just returns the point given to it.

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Best regards,

Henrik

From: Pharo-dev [mailto:pharo-dev-bounces@lists.pharo.org] On Behalf Of Aliaksei Syrel
Sent: Wednesday, January 27, 2016 4:12 PM
To: Pharo Development List <pharo-dev@lists.pharo.org>
Subject: [Pharo-dev] Morphic magician requested. What is referencePosition?

Hi

Do anyone know what is Morph>>#referencePosition and why is it used to handle drag and drop?

Here is what method doc says:

"Return the current reference position of the receiver"

Thanks,

Alex