add squirclepath method

docs/src/howto/simplegraphics.md

@@ -1073,9 +1073,24 @@ end
 finish() # hide
 nothing # hide
 ```
-
 ![squircles](../assets/figures/squircle.png)
 
+`squirclepath()` builds a squircle shape using Bézier curves as paths, rather than using polygons. Here, `kappa` determines the circularity. 
+
+```@example
+using Luxor # hide
+@drawsvg begin # hide
+    background("grey10") # hide
+    setfillrule(:even_odd)
+    sethue("white")
+    for x in 280:-10:10
+    squirclepath(O, x, x;
+        kappa = x/150, action=:path)
+    end 
+    fillpath()
+end 800 700 # hide
+```
+
 ## Stars and crosses
 
 Use [`star`](@ref) to make a star. You can draw it immediately, or use the array of points it can create.

src/curves.jl

@@ -272,7 +272,7 @@ the shape is a resonable approximation to a circle.
 Use the `reversepath` option to construct the path in the opposite direction.
 
 The difference betweeen `squircle()` and `squirclepath()` is that the former
-builds polygons from points, the latter uses Bezier curves to build paths.
+builds polygons from points, the latter uses Bezier curves to build paths. 
 
 See also `circlepath()`.
 """
@@ -302,6 +302,15 @@ function squirclepath(cpos, w, h;
     end
     return result
 end
+
+squirclepath(cpos, w, h, the_action::Symbol;
+        action = :none,
+        kappa = 0.75,
+        reversepath = false) = squirclepath(cpos, w, h;
+        action = the_action,
+        kappa = kappa,
+        reversepath = reversepath)
+
 function arc(xc, yc, radius, angle1, angle2;
     action = :none)
     Cairo.arc(_get_current_cr(), xc, yc, radius, angle1, angle2)