Hi Renaud,

Yes, I use Spec with the Morphic graphical library and with the calculation that you described, I got the correct answer for the coordinates within the Morph representing the image (Form). Because I was using an autoscaling image, I had then to do one more step by scaling the local coordinates according to the scale of the image, but that was very easy.

Thanks!

Kind regards,

Mikael

Fr��n: Renaud de Villemeur via Pharo-users [mailto:pharo-users@lists.pharo.org]
Skickat: den 5 mars 2025 02:13
Till: Any question about pharo is welcome
Kopia: Any question about pharo is welcome; Renaud de Villemeur
��mne: [Pharo-users] Re: Converting global coordinates from a mouse event

Hi Mikael

I assume you use spec with the Morphic underlying graphical library.

In your presenter: 

- `anEvent position` will give you the event position in the global world coordinate.

- `self adapter widget position.` will give you the top left corner underlying Morph position in the global world coordinate.

`anEvent position - self adapter widget position` should give you the position you're looking for.

Renaud

Mar 3, 2025, 03:17 by mikael.svane@fridhem.org:

I have a presenter that is a subclass of SpPresenterWithModel and it contains, among other things, an ImagePresenter with an autoscaling image (a Form). I want to capture mouse clicks on the image and get the coordinate of the click relative to the upper left corner of the Form.

My #initializePresenter method looks like this:

initializePresenter

                           image := self newImage

                                                       image: self emptyImage;

                                                       autoScale: true.

                           image eventHandler whenMouseDownDo: [ :event |

                                                                                  self handleMouseDown: event].

This works, and the #handleMouseDown: method is run whenever the mouse is pressed on the ImagePresenter, but the MouseButtonEvent reports global coordinates and I can���t find out how to convert these to coordinates relative to the Form that the ImagePresenter holds. I have googled and found answers to similar old questions, but nothing that seems to apply to Spec2.

There must be a very simple solution to this, it���s just that I can���t seem to find it.

Kind regards,

Mikael