[Cuis-dev] Morphic events changes proposal

[Juan Vuletich]

Hi Luciano,

These are very neat. Thank you!

They are now at GitHub.

Cheers,

On 2025-11-22 9:36 AM, Luciano Notarfrancesco via Cuis-dev wrote:
> This is a little tweak intended to be applied on top of the previous 
> change set. When the preference focusFollowsMouse is enabled, it 
> prevents doing it while the hand is dragging something.
>
> On Mon, Nov 17, 2025 at 3:10 PM Luciano Notarfrancesco 
> <luchiano at gmail.com> wrote:
>
>     Here's the changes I recently made to Morphic events to try and
>     improve drag & drop. Let me know what you think. The change set
>     adds the following protocol:
>     - Morph>>dragEnter: and dragLeave: analogous to the existing
>     mouseEnter:, mouseLeave: and mouseHover:localPosition:, but they
>     are only called when the hand is dragging something (i.e., it's
>     not empty, has submorphs) and the morph answers true to
>     handlesDragOver: (analogous to the existing handlesMouseOver:);
>     - Morph>>dragHover:localPosition: and handlesDragHover (parallel
>     to the existing mouseHover:localPosition: and handlesMouseHover);
>     - Morph>>dragCancel is called by the hand if the user presses ESC
>     while dragging this morph; this gives the dragged morph an
>     opportunity to cancel the drag, for example by deleting itself or
>     returning to its original owner and position (but by default does
>     nothing).
>
>     Also, I fixed a problem when creating MouseScrollEvents: the
>     vertical direction was given priority, and horizontal scroll
>     events were missed. And I also added a delta instance variable to
>     MouseScrollEvent, instead of throwing it away, so a consumer of
>     the event has the opportunity to scroll in both directions
>     simultaneously and at the correct speed. This information is
>     optional, and might not be available in all platforms (I tried
>     only Mac), but from what I read it is now quite standard (except
>     in legacy Linux X11). It's very useful for navigating a ZUI, which
>     is what I'm doing.
>
>     Other systems also separate mouseEnter/etc from dragEnter/etc, so
>     I tried to do the same, I don't want to reinvent anything. Let me
>     know if anyone has any better or different ideas.
>
>     The change set also includes some unrelated changes, please
>     review: a method to draw arcs that was missing in
>     AbstractVectorCanvas, and two methods to scale and translate
>     PlacedMorphs (I'm not sure if the best selector is scaleBy:around:
>     or scaleBy:about:).
>
>
-- 
Juan Vuletich
www.cuis.st
github.com/jvuletich
researchgate.net/profile/Juan-Vuletich
independent.academia.edu/JuanVuletich
patents.justia.com/inventor/juan-manuel-vuletich
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