Shapes are defined by control points. A point is selected when it filled (white) i.e.
|•||To select multiple points, use CTRL + Click|
|•||To de-select a point, CTRL + Click it again|
|•||To de-select all points, click outside the shape|
To add a point to a shape, enable the Add Point button and click on the shape edge.
A bezier shape is a spline and is defined by a number of bezier control points.
Each control point has tangent handles on each side of the point that allow fine control of the curve of the shape at the point.
Shape showing bezier-style control point and tangent handles.
One tangent handle "broken" (not mirror of other) using SHIFT+CTRL drag handle.
The basic ellipse and bezier shapes are defined by bezier style points whereas the basic rectangle and polygon shapes are defined by standard non-bezier points. Any points manually added to any shape will be a bezier type.
You can access and pull out the tangent handles on a sharp cornered bezier shape by dragging the corner point while holding down the keyboard z key :
Keyboard : z + drag (mouse)
Breaking a Shape
You can break a corner of a shape by holding down the keyboard SHIFT + CTRL keys while dragging the point.
To re-join the two points, hold down SHIFT+CTRL and drag one point on top of the other. The two points should snap together when close.