bug fixes

CHANGELOG.md

@@ -9,6 +9,8 @@
 
 ### Changed
 
+- check for dodgy corners in `polysmooth()` (thanks @arbitrandomuser!)
+
 ### Removed
 
 ### Deprecated

docs/src/howto/polygons.md

@@ -1400,14 +1400,13 @@ You supply two polygons and a value `k` between 0 and 1. For example, if the val
 
 Sometimes polygons consist of two or more loops - this is how holes work. So `polymorph()` accepts both simple polygons and arrays of polygons, but always returns an array of polygons.
 
-In this first example, `fromshape`, the circle, is an array holding a single vector of Points (`pathtopoly()` returns an array of poygons), and `toshape`, the line, is a simple vector of points (the minimum of three points). In this case, with just simple polygons, only the first element of the result of the `polymorph()` function is needed.
+In this first example, `fromshape`, the circle, is an array holding a single vector of Points (`pathtopoly()` returns an array of polygons), and `toshape`, the line, is a simple vector of points (the minimum of three points). In this case, with just simple polygons, only the first element of the result of the `polymorph()` function is needed.
 
 ```@example
 using Luxor # hide
-@drawsvg begin
-background("black")
-setline(0.5)
-sethue("gold")
+@drawsvg begin # hide
+background("black") # hide
+setline(0.5) # hide
 circlepath(O, 200, :path)
 fromshape = pathtopoly()
 toshape = [Point(0, -250), O, Point(0, 250)] # minimum of 3
@@ -1416,15 +1415,15 @@ for i in 0:0.015:1
     morph = polymorph(fromshape, toshape, i, easingfunction=easeinoutsine)
     poly(first(morph), :stroke, close=true)
 end
-end
+end # hide
 ```
 
 In the next example, a square morphs into a hexagon.
 
 ```@example
 using Luxor # hide
 @drawsvg begin # hide
-background(0.15, 0.15, 0.1)
+background(0.15, 0.15, 0.1) # hide
 pgon1 = ngon(O, 80, 4,  vertices = true)
 pgon2 = ngon(O, 270, 6, vertices = true)
 sethue("cyan")
@@ -1443,8 +1442,7 @@ In the next example, an octagon with a square hole morphs into a square with an
 ```@example
 using Luxor # hide
 @drawsvg begin # hide
-background(0.15, 0.15, 0.1)
-
+background(0.15, 0.15, 0.1) # hide
 # build first polygon
 ngon(O + (-350, 0), 40, 8, π, :path)
 newsubpath()
@@ -1501,4 +1499,4 @@ animate(amovie, Scene(amovie, frame, 1:120), creategif=true, pathname="/tmp/pyth
 
 ![python julia animation](../assets/figures/python-julia.gif)
 
-The length of "Python" is 9, whereas the length of "Julia" is 8. The `polymorph()` function tries to work around this - notice how the "n" morphs down to nothing. If you don't want this to happen, set `kludge` to false. In this particular case, you could increase the number of loops in `totext` to match by using a lower-case "j".
+The "Python" path has 9 loops, whereas "Julia" has 8. The `polymorph()` function tries to work around this - notice how the ninth loop, "n", morphs down to nothing. If you don't want this to happen, set the `kludge` keyword to false. In this particular case, you could increase the number of loops in `totext` to match by using a lower-case "j".

src/polygons.jl

@@ -375,6 +375,9 @@ prettypoly(pointlist, action::Symbol) = prettypoly(pointlist, () -> circle(O, 2,
     vertexlabels = (n, l) -> ())
 
 function getproportionpoint(point::Point, segment, length, dx, dy)
+    if isapprox(segment, 0.0) || isapprox(length, 0.0)
+        throw(error("getproportionpoint: impossible construction with segment $(segment) length $(length)"))
+    end
     scalefactor = segment / length
     return Point((point.x - dx * scalefactor), (point.y - dy * scalefactor))
 end
@@ -482,6 +485,9 @@ function polysmooth(points::Array{Point,1}, radius, action::Symbol; debug = fals
             p1 = points[mod1(i, l)]
             p2 = points[mod1(i + 1, l)]
             p3 = points[mod1(i + 2, l)]
+            if isapprox(distance(p1, p2), 0.0) || isapprox(distance(p2, p3), 0.0)
+                throw(error("polysmooth(): impossible to round the vertex at point #$(i + 1)"))
+            end 
             drawroundedcorner(p2, p1, p3, radius, temppath, debug = debug)
         end
     end