Ensure inverting clip extents always works.

In other words, when drawing the geometry {type: "Sphere"}, inverting
the generated points should ideally result in points inside the
corresponding sub-projection’s region in spherical coordinates.

d3.js

@@ -3424,8 +3424,8 @@ d3 = function() {
       if (!arguments.length) return lower48.translate();
       var k = lower48.scale(), x = +_[0], y = +_[1];
       lower48.translate(_).clipExtent([ [ x - .455 * k, y - .238 * k ], [ x + .455 * k, y + .238 * k ] ]);
-      alaska.translate([ x - .307 * k, y + .201 * k ]).clipExtent([ [ x - .425 * k, y + .12 * k ], [ x - .214 * k, y + .234 * k ] ]);
-      hawaii.translate([ x - .205 * k, y + .212 * k ]).clipExtent([ [ x - .214 * k, y + .166 * k ], [ x - .115 * k, y + .234 * k ] ]);
+      alaska.translate([ x - .307 * k, y + .201 * k ]).clipExtent([ [ x - .425 * k + ε, y + .12 * k + ε ], [ x - .214 * k - ε, y + .234 * k - ε ] ]);
+      hawaii.translate([ x - .205 * k, y + .212 * k ]).clipExtent([ [ x - .214 * k + ε, y + .166 * k + ε ], [ x - .115 * k - ε, y + .234 * k - ε ] ]);
       return albersUsa;
     };
     return albersUsa.scale(1070);

src/geo/albers-usa.js

@@ -102,11 +102,11 @@ d3.geo.albersUsa = function() {
 
     alaska
         .translate([x - .307 * k, y + .201 * k])
-        .clipExtent([[x - .425 * k, y + .120 * k], [x - .214 * k, y + .234 * k]]);
+        .clipExtent([[x - .425 * k + ε, y + .120 * k + ε], [x - .214 * k - ε, y + .234 * k - ε]]);
 
     hawaii
         .translate([x - .205 * k, y + .212 * k])
-        .clipExtent([[x - .214 * k, y + .166 * k], [x - .115 * k, y + .234 * k]]);
+        .clipExtent([[x - .214 * k + ε, y + .166 * k + ε], [x - .115 * k - ε, y + .234 * k - ε]]);
 
     return albersUsa;
   };