[Feature]: Possibility to define custom attributes per control about fabric.js

[asturur]

When doing the first version of the control api, that is the one that is still available today, there were 2 way to define controls properties. On the object and with styleOverrides.

The reasoning was that we would see what was the usage and we would change depending on feedback.
At the moment duplicating the setting on the object and on the control and then deciding which one has the priority didn't look good ( it doesn't to me also today ).

You can create a custom render function, let's say you want to render a circle, pass a render option to your control:

      acc[`newPoint${index}`] = new fabric.Control({
          positionHandler: this.newPointPolygonPositionHandler.bind(this, index),
          mouseUpHandler: this.newPointAnchorWrapper(index),
          actionName: "newPointPolygon",
          cursorStyle: "copy",
          render: function(
                          ctx: CanvasRenderingContext2D,
                          left: number,
                          top: number,
                          styleOverride: ControlRenderingStyleOverride | undefined,
                          fabricObject,
                       )  {
        renderCircleControl.call(
          this,
          ctx,
          left,
          top,
          styleOverride: {
             cornerColor: 'specialColorYouWant'
           }
          fabricObject,
        );
      }
  })

this is a way to do it.
You can also define this control as a subclass of the standard control and keep it as a preconfigured class

[elerocks]

thank you @asturur ! That's exactly what I needed.
Additional question, is it possible to catch right click event on fabric.Control? I've only managed to catch left click (using the mouseUpHandler)

[asturur]

ah. If it doesn't fire no, but i would agree it would be sort of normal to have it?
It probably doesn't work because if the click is not left with let go the whole function and we stop checking.

Maybe you can use _findTargetCorner on the activeObject on a generic mouseUp/mouseDown on the canvas and call the control mouseUp handler manually?

This could be something we could support out of the box, you should open a separate feature request for it

[elerocks]

Thank you, separate feature request filed. I think this issue can be closed.