Shape: Diamond

The diamond shape is generated, as most shapes are, on a square canvas to the maximum of either horizontal or vertical measurement up to the composite canvas size.

The diamond is a four sided polygon with proportional sides and no skips (poly_4_0).
Compare the generated shape with the composited shape and you can see the vertical squeezing.

Generating shapes in this manner allows us to change the line thickness proportionally over the entire shape, resulting in the same shape on the inside and outside edges (compare to GDI generated shapes with thick lines).