On primitive Pythagorean triples of special forms

We explore primitive Pythagorean triples of special forms $(a,b,b+g)$ and $(a,a+f,c)$, with $g,f\in\mathbb{Z}^+$. For each $g$ and $f$, we provide a method to generate infinitely many such primitive triples. Lastly, for each $g$, we describe the asymptotic density of primitive $(a,b,b+g)$ triples within all primitive triples of the same parity.