Hi, This is a corner case that is not considered in Spec design: In fact what you are doing is changing the content of the model and you need the presenter to react to it. Indeed, as Stef says the solution is to re-set the image to the image presenter when performing the change: myPresenter image: modifiedForm. You may think something like that should be done in the `updatePresenter` message (but updatePresenter does not has a mean in "widget" presenters).... or like the `refresh` message for lists/tables, and you would be right (I will add a refresh message to SpImagePresenter). But at the end, it will end up doing exactly that, so you are safe workaround it the thing :) Esteban On 3/8/25 21:03, sducasseatwork--- via Pharo-users wrote:

Hi Mikael

I do not know the answer so I tried to find it. Indeed the superclass>>updatePresenter is empty :(

Let us see what esteban will reply. Now I tried to check the morphic back end.

Now writing directly on the canvas this way does not look the right way. Did you try with SpMorphPresenter or SpRoassalPresenter because you have access to the cairo canvas.

While browsing the code of the SpMorphicROassalAdapter I saw

widget sessionChanged.

SpAbstractMorphicAdapter I saw changed.

changed

^ self widgetDo: [ :w | w changed ]

I also saw in SpAbstractAdapter isRedrawable so I wonder if it should not be true on the Adapter corresponding to the SpImagePresenter (if any)

BTW the SpMorphicAthensAdapter defines a method redraw (Athens is the cairo wrapper used also in Roassal)

Reading the code of SpMorphicImageAdapter >> buildWidget

| alphaImage | alphaImage := AlphaImageMorph new. alphaImage model: self. alphaImage getImageSelector: #getImage; vResizing: #spaceFill; hResizing: #spaceFill; layout: self layoutValue; dragEnabled: self dragEnabled; dropEnabled: self dropEnabled; setBalloonText: self help; update: #getImage.

self model whenImageChangeDo: [ alphaImage image: (self getImage ifNil: [ Form extent: 1 @ 1 depth: 32 ]) ]; whenAutoScaleChangeDo: [ widget layout: self layoutValue ].

^ alphaImage

It feels like we should reassign the image:

Did you try something like

...

updatePresenter                           self image: self image?

...

On 7 Mar 2025, at 18:11, Mikael Svane <mikael.svane@fridhem.org> wrote:

I have a Form where I change pixel colours using Form>>pixelValueAt:put:. The Form exists inside an SpImagePresenter. After having changed the pixels, I want to redraw the Form in an #updatePresenters method to show the changes, but I haven’t been able to figure out how to do this. If I inspect the Form it is clear that the pixels have been changed, so the problem is in the #updatePresenters mwthod. I have tried different variations on this theme without success: updatePresenter                            | canvas |                            “Get the canvas of the Form:”                            canvas := imagePresenter image form getCanvas.                            adapter widget drawSubmorphsOn: canvas Any suggestions would be very welcome. Kind regards, Mikael