Added source code

utils/core/rounded_rectangle.scad

@@ -0,0 +1,33 @@
+//
+// NopSCADlib Copyright Chris Palmer 2018
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+
+//
+//! Rectangle with rounded corners.
+//
+module rounded_square(size, r, center = true) //! Like ```square()``` but with with rounded corners
+{
+    $fn = r2sides4n(r);
+    offset(r) offset(-r) square(size, center = center);
+}
+
+module rounded_rectangle(size, r, center = true, xy_center = true) //! Like ```cube()``` but corners rounded in XY plane and separate centre options for xy and z.
+{
+    linear_extrude(height = size[2], center = center)
+        rounded_square([size[0], size[1]], r, xy_center);
+}