Created attachment 97026 [details]
Proposed "Rounded rectangle"-type callout with customizable shape

Currently the shape of the "rounded rectangle"-type callouts is fixed. 
(a) Only the "beak" part of the callout can be moved.
(b) The rounding looks ugly (not symmetrical), especially for small heights

Often the "beak" of the callout becomes too thin or too thick, and looks ugly.

But the user has no control on it.

This is a major limitation in making the presentation attractive.

DESIRED:

Please see the attached file for a sample of better-shaped callout.

This simulated callout has the following features:
1. Handles to control the rounding radius (separate for x and y directions)
2. Handles to move the "beak" along the periphery of the rectangle
   (this also controls the base-width of the beak)