region: correct the point-region distance2 calculation

region.hpp

@@ -233,11 +233,12 @@ namespace cruft {
     distance2 (region<S,T> r, point<S,T> p)
     {
         auto const clamped = cruft::max (
-            cruft::min (p, r.p + r.e),
+            r.p - p,
-            r.p
+            vector<S,T> (0),
+            p - (r.p + r.e)
         );
 
-        return distance2 (r.p, clamped);
+        return sum (clamped * clamped);
     }
 
 

test/region.cpp

@@ -102,5 +102,39 @@ main (int, char **)
         tap.expect (success, "make_range(region2i)");
     };
 
+    // test distance2 for points
+    {
+        struct {
+            cruft::region2f r;
+            cruft::point2f  p;
+            float distance2;
+            char const *message;
+        } const TESTS[] = {
+            {
+                { cruft::point2f { 1, 1 }, cruft::point2f { 3, 5 } },
+                { 0, 0 },
+                2.f,
+                "origin to offset rect"
+            },
+            {
+                { cruft::point2f { 1, 1 }, cruft::point2f { 3, 5 } },
+                { 2, 2 },
+                0.f,
+                "point inside region"
+            },
+            {
+                { cruft::point2f { 1, 1 }, cruft::point2f { 3, 5 } },
+                { 4, 7 },
+                1 + 4,
+                "offset point to offset rect"
+            },
+        };
+
+        for (auto const &t: TESTS) {
+            auto const d2 = distance2 (t.r, t.p);
+            tap.expect_eq (d2, t.distance2, "region-point distance2: %!", t.message);
+        }
+    };
+
     return tap.status ();
 }