Drag & Drop line drawing.

How to

The idea is to draw a temporary SVG path while the user is creating the line by drag&drop. When the user releases the mouse cursor when in the line drawing mode (creatingLine === true), we create the JointJS basic.Path shape based on the line coordinates gathered during the drawing. The result of this is a normal JointJS shapes that we can put the ui.Halo and/or ui.FreeTransform control panels around.