Also there is another method that you can find in Chris McCormick's s-abstractions s-controlsurface: https://mccormick.cx/projects/s-abstractions/. The method is to traverse the pointer to the subpatch and then use [next( so many times until you reach the desired scalar. Which you then can access.

Edit: i should add that the way Chris McCormick does it, the scalars are appended to the head of the subpatch (same as i did above). Therefore the last added scalar becomes the first in the subpatch and [next( is therefore not in the expected order. Anyhow it should be possible to implement it correctly (only traverse the pointer of the append on load and on clear or instead count elements and use inverse number), but i couldn't quite figure it out on first try, so i just recommend the above method with lists which also gives the most control in my opinion

So we still use [get], we just don't use [element] anymore to select the scalar. There i was not clear in one previous post.

As far as constrained dragging, you can do it in Purr Data fairly easily:

purr-dragger.pd

As far as constrained dragging on array elements, you can do that in Purr Data as well:

purr-dragger-array.pd

A few notes:

• the "drag" event is set on the relevant [draw] command and sends notifications to the outlet of the relevant [draw] command. This allows "per-shape" events so you can tell which shape triggered the event.
• since these draw events aren't turned on by default, you can decide which events you want to listen for-- mousedown, mouseup, mouseover, mouseout, mouseenter, mouseleave, and drag. (Scroll and touch events are possible but I haven't implemented them.)
• for the sake of sanity "x" and "y" fields don't have any automatic behavior when scalar elements are drawn using [draw array]. If you want to make associations you can declare them in a message as I do in the demo.
• [draw array] has no bounding box to select it in Edit mode. Otherwise it would try to get the bounding box for all its elements and cause dropouts for arrays of non-trivial size every time you move the mouse. To get a bbox you can nest it inside a [draw svg] which creates a viewport clipped to a rectangle you can specify.
• receiving events for ds array elements is fairly new behavior. I know there's at least one crasher lurking if you try to add fields to the [struct] for an array element with extant scalars on a canvas.

Edit: clarification

hi,

I've got a purrdata patch that uses draw-array with per-shape events. it's really great for user definded interaction.
Here's what I've got so far:

purr-ds-array-interaction.zip