working on recipes

src/recipes.jl

@@ -9,6 +9,16 @@ plot!(recipe::PlotRecipe, args...; kw...) = plot!(getRecipeXY(recipe)..., args..
 plot!(plt::Plot, recipe::PlotRecipe, args...; kw...) = plot!(getRecipeXY(recipe)..., args...; getRecipeArgs(recipe)..., kw...)
 
 
+# -------------------------------------------------
+
+function rotate(x::Real, y::Real, θ::Real; center = (0,0))
+    cx = x - center[1]
+    cy = y - center[2]
+    xrot = cx * cos(θ) - cy * sin(θ)
+    yrot = cy * cos(θ) + cx * sin(θ)
+    xrot + center[1], yrot + center[2]
+end
+
 # -------------------------------------------------
 
 type EllipseRecipe <: PlotRecipe
@@ -22,24 +32,21 @@ EllipseRecipe(w,h,x,y) = EllipseRecipe(w,h,x,y,0)
 
 # return x,y coords of a rotated ellipse, centered at the origin
 function rotatedEllipse(w, h, x, y, θ, rotθ)
-    # coord before rotation
+    # # coord before rotation
     xpre = w * cos(θ)
     ypre = h * sin(θ)
-    
-    # rotate
-    xrot = xpre * cos(rotθ) + ypre * sin(rotθ)
-    yrot = ypre * cos(rotθ) - xpre * sin(rotθ)
 
-    # translate
-    xrot + x, yrot + y
+    # rotate and translate
+    r = rotate(xpre, ypre, rotθ)
+    x + r[1], y + r[2]
 end
 
 function getRecipeXY(ep::EllipseRecipe)
     x, y = unzip([rotatedEllipse(ep.w, ep.h, ep.x, ep.y, u, ep.θ) for u in linspace(0,2π,100)])
-    right = rotatedEllipse(ep.w, ep.h, ep.x, ep.y, 0, ep.θ)
-    top = rotatedEllipse(ep.w, ep.h, ep.x, ep.y, 0.5π, ep.θ)
-    linex = Float64[top[1], ep.x, right[1]]
-    liney = Float64[top[2], ep.y, right[2]]
+    top = rotate(0, ep.h, ep.θ)
+    right = rotate(ep.w, 0, ep.θ)
+    linex = Float64[top[1], 0, right[1]] + ep.x
+    liney = Float64[top[2], 0, right[2]] + ep.y
     Any[x, linex], Any[y, liney]
 end