A demonstration of this bug.
The resulting diagram should show all intersection points between an edge and the boundaries of its nodes. As you can see, some are missing. Changing r at line 26 to 7 results in different missed intersections. Most other values of r result in all intersections being found.
vmap and es were originally generated by diagrams-graphviz.
| #!/usr/bin/env cabal | |
| {- cabal: | |
| build-depends: base,containers,diagrams-lib,diagrams-svg | |
| -} | |
| module Main where | |
| import Data.Map (Map,(!)) | |
| import qualified Data.Map as Map | |
| import Diagrams.Backend.SVG.CmdLine | |
| import Diagrams.Prelude | |
| main :: IO () | |
| main = mainWith graph | |
| graph :: Diagram B | |
| graph = mconcat edgeArrows <> (mconcat nodeTrails # lc blue) | |
| where | |
| nodeTrails = map stroke $ Map.elems nodes | |
| edgeArrows = map (\(v1,v2,p) -> edgeArrow p (nodes ! v1) (nodes ! v2)) es | |
| nodes = node <$> vmap | |
| node :: P2 Double -> Located (Trail V2 Double) | |
| node p = (circle r `at` translate (V2 r 0) p) | |
| where r = 6 | |
| edgeArrow :: Located (Trail V2 Double) -> Located (Trail V2 Double) -> Located (Trail V2 Double) -> Diagram B | |
| edgeArrow tr t1 t2 = stroke tr <> mconcat is1 <> mconcat is2 | |
| where | |
| is1 = map (\p -> circle 0.7 # moveTo p # lc green) $ intersectPoints tr t1 | |
| is2 = map (\p -> circle 1.0 # moveTo p # lc red ) $ intersectPoints tr t2 | |
| vmap :: Map Int (Point V2 Double) | |
| vmap = | |
| Map.fromList | |
| [ | |
| ( 2 | |
| , P ( V2 73.0 14.0 ) | |
| ) | |
| , | |
| ( 3 | |
| , P ( V2 36.5 14.0 ) | |
| ) | |
| , | |
| ( 1 | |
| , P ( V2 0.0 0.0 ) | |
| ) | |
| ] | |
| es :: [(Int, Int, Located (Trail V2 Double))] | |
| es = | |
| [ | |
| ( 1 | |
| , 3 | |
| , Trail | |
| ( lineFromSegments | |
| [ bézier3 ( V2 1.9888 0.795509 ) ( V2 32.876599999999996 13.150839000000001 ) ( V2 34.8056 13.921839 ) ] | |
| ) `at` P ( V2 1.1004 4.0161e-2 ) | |
| ) | |
| , | |
| ( 1 | |
| , 2 | |
| , Trail | |
| ( lineFromSegments | |
| [ bézier3 ( V2 1.197 0.11278329999999999 ) ( V2 20.5887 1.9646333 ) ( V2 35.9417 4.9945333 ) | |
| , bézier3 ( V2 15.265 3.012600000000001 ) ( V2 33.801 8.635 ) ( V2 34.944 8.983 ) | |
| ] | |
| ) `at` P ( V2 1.0583 5.4667e-3 ) | |
| ) | |
| , | |
| ( 3 | |
| , 3 | |
| , Trail | |
| ( lineFromSegments | |
| [ bézier3 | |
| ( V2 ( -8.583000000000002 ) 6.086 ) | |
| ( V2 ( -8.444000000000003 ) 17.714 ) ( V2 0.41499999999999915 17.714 ) | |
| , bézier3 ( V2 8.859000000000002 0.0 ) | |
| ( V2 8.997999999999998 ( -11.628 ) ) | |
| ( V2 0.41499999999999915 ( -17.714 ) ) | |
| ] | |
| ) `at` P ( V2 36.085 14.286 ) | |
| ) | |
| , | |
| ( 3 | |
| , 2 | |
| , Trail | |
| ( lineFromSegments | |
| [ bézier3 | |
| ( V2 1.044000000000004 ( -8.4487 ) ) | |
| ( V2 33.922999999999995 ( -8.4466 ) ) ( V2 34.949999999999996 5.999999999998451e-3 ) | |
| ] | |
| ) `at` P ( V2 37.025 13.585 ) | |
| ) | |
| , | |
| ( 2 | |
| , 3 | |
| , Trail | |
| ( lineFromSegments | |
| [ bézier3 | |
| ( V2 ( -1.027000000000001 ) 8.452999999999998 ) | |
| ( V2 ( -33.90599999999999 ) 8.455 ) | |
| ( V2 ( -34.949999999999996 ) 5.999999999998451e-3 ) | |
| ] | |
| ) `at` P ( V2 71.975 14.409 ) | |
| ) | |
| , | |
| ( 2 | |
| , 2 | |
| , Trail | |
| ( lineFromSegments | |
| [ bézier3 | |
| ( V2 ( -8.582999999999998 ) 6.086 ) | |
| ( V2 ( -8.443999999999988 ) 17.714 ) ( V2 0.41500000000000625 17.714 ) | |
| , bézier3 ( V2 8.858999999999995 0.0 ) | |
| ( V2 8.998000000000005 ( -11.628 ) ) | |
| ( V2 0.41500000000000625 ( -17.714 ) ) | |
| ] | |
| ) `at` P ( V2 72.585 14.286 ) | |
| ) | |
| ] |
| <?xml version="1.0" encoding="UTF-8"?> | |
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