Added source code

utils/annotation.scad

@@ -0,0 +1,40 @@
+//
+// 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/>.
+//
+include <../core.scad>
+//
+//! Annotation used in this documentation
+
+module label(str, scale = 0.25, valign = "baseline", halign = "left") //! Draw text that always faces the camera
+    color("black")
+        %rotate($vpr != [0, 0, 0] ? $vpr : [70, 0, 315])
+            linear_extrude(height = eps)
+                scale(scale)
+                    text(str, valign = valign, halign = halign);
+
+module arrow(length = 20) { //! Draw an arrow that faces downwards
+    d = length / 20;
+    head_r = 1.5 * d;
+
+    color("grey") %union() {
+        translate_z(head_r)
+            cylinder(d = d, h = length - head_r, $fn = 32);
+
+        cylinder(r1 = 0, r2 = head_r, h = head_r);
+    }
+}