fix a race condition with coincident chain of holes

Closes #111.
mapbox · Feb 5, 2019 · 7564bd1 · 7564bd1
1 parent ad016a4
commit 7564bd1
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Showing 3 changed files with 10 additions and 3 deletions.
diff --git a/src/earcut.js b/src/earcut.js
@@ -449,7 +449,7 @@ function getLeftmost(start) {
     var p = start,
         leftmost = start;
     do {
-        if (p.x < leftmost.x) leftmost = p;
+        if (p.x < leftmost.x || (p.x === leftmost.x && p.y < leftmost.y)) leftmost = p;
         p = p.next;
     } while (p !== start);
 

diff --git a/test/fixtures/issue111.json b/test/fixtures/issue111.json
@@ -0,0 +1,6 @@
+[
+[[800,4520],[800,4700],[796,4702],[800,4692],[734,4644],[734,4628],[730,4632],[726,4630],[718,4640],[690,4623],[722,4598],[690,4608],[690,4520],[800,4520]],
+[[718,4640],[716,4630],[710,4628],[718,4640]],
+[[734,4610],[734,4628],[740,4622],[734,4610]],
+[[734,4610],[745,4600],[734,4602],[734,4610]]
+]
diff --git a/test/test.js b/test/test.js
@@ -12,8 +12,8 @@ areaTest('water2', 1212);
 areaTest('water3', 197);
 areaTest('water3b', 25);
 areaTest('water4', 705);
-areaTest('water-huge', 5174, 0.0011);
-areaTest('water-huge2', 4461, 0.0028);
+areaTest('water-huge', 5175, 0.0011);
+areaTest('water-huge2', 4462, 0.0028);
 areaTest('degenerate', 0);
 areaTest('bad-hole', 42, 0.019);
 areaTest('empty-square', 0);
@@ -37,6 +37,7 @@ areaTest('shared-points', 4);
 areaTest('bad-diagonals', 7);
 areaTest('issue83', 0);
 areaTest('issue107', 0);
+areaTest('issue111', 0);
 
 test('indices-2d', function (t) {
     var indices = earcut([10, 0, 0, 50, 60, 60, 70, 10]);