New ->translate() method for ExPolygon::XS

xs/src/ExPolygon.hpp

@@ -20,6 +20,7 @@ class ExPolygon
     Polygons holes;
     SV* arrayref();
     void scale(double factor);
+    void translate(double x, double y);
 };
 
 #define scale_polygon(poly, factor) \
@@ -28,6 +29,12 @@ class ExPolygon
         (*pit).y *= factor; \
     }
 
+#define translate_polygon(poly, x, y) \
+    for (Polygon::iterator pit = (poly).begin(); pit != (poly).end(); ++pit) { \
+        (*pit).x += x; \
+        (*pit).y += y; \
+    }
+
 void
 ExPolygon::scale(double factor)
 {
@@ -37,6 +44,15 @@ ExPolygon::scale(double factor)
     }
 }
 
+void
+ExPolygon::translate(double x, double y)
+{
+    translate_polygon(contour, x, y);
+    for (Polygons::iterator it = holes.begin(); it != holes.end(); ++it) {
+        translate_polygon(*it, x, y);
+    }
+}
+
 void
 perl2polygon(SV* poly_sv, Polygon& poly)
 {

xs/t/04_expolygon.t

@@ -4,7 +4,7 @@ use strict;
 use warnings;
 
 use Slic3r::XS;
-use Test::More tests => 6;
+use Test::More tests => 7;
 
 my $square = [  # ccw
     [100, 100],
@@ -30,10 +30,17 @@ my $clone = $expolygon->clone;
 is_deeply [ @$clone ], [$square, $hole_in_square], 'clone';
 # TODO: check that modifying the clone doesn't modify the original one
 
-$expolygon->scale(1.5);
+$expolygon->scale(2.5);
 is_deeply [ @$expolygon ], [
-    [map [ 1.5*$_->[0], 1.5*$_->[1] ], @$square],
-    [map [ 1.5*$_->[0], 1.5*$_->[1] ], @$hole_in_square]
+    [map [ 2.5*$_->[0], 2.5*$_->[1] ], @$square],
+    [map [ 2.5*$_->[0], 2.5*$_->[1] ], @$hole_in_square]
     ], 'scale';
 
+$expolygon->scale(1/2.5);
+$expolygon->translate(10, -5);
+is_deeply [ @$expolygon ], [
+    [map [ $_->[0]+10, $_->[1]-5 ], @$square],
+    [map [ $_->[0]+10, $_->[1]-5 ], @$hole_in_square]
+    ], 'translate';
+
 __END__