From 231ceb70f2dd7e83db3bd2bea961c73401ab6e21 Mon Sep 17 00:00:00 2001
From: Phil Howard <phil@gadgetoid.com>
Date: Wed, 6 Sep 2023 09:40:38 +0100
Subject: [PATCH] PicoVector: Add basic polygon center of mass function.

---
 micropython/modules/picovector/picovector.c   |  2 ++
 micropython/modules/picovector/picovector.cpp | 18 ++++++++++++++++++
 micropython/modules/picovector/picovector.h   |  1 +
 3 files changed, 21 insertions(+)

diff --git a/micropython/modules/picovector/picovector.c b/micropython/modules/picovector/picovector.c
index 3cbfacdf..eb6dfd1f 100644
--- a/micropython/modules/picovector/picovector.c
+++ b/micropython/modules/picovector/picovector.c
@@ -3,10 +3,12 @@
 /* Polygon */
 
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(POLYGON__del__obj, POLYGON__del__);
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(POLYGON_centroid_obj, POLYGON_centroid);
 
 
 STATIC const mp_rom_map_elem_t POLYGON_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&POLYGON__del__obj) },
+    { MP_ROM_QSTR(MP_QSTR_centroid), MP_ROM_PTR(&POLYGON_centroid_obj) },
 };
 
 STATIC MP_DEFINE_CONST_DICT(POLYGON_locals_dict, POLYGON_locals_dict_table);
diff --git a/micropython/modules/picovector/picovector.cpp b/micropython/modules/picovector/picovector.cpp
index 11dcdddd..9654c342 100644
--- a/micropython/modules/picovector/picovector.cpp
+++ b/micropython/modules/picovector/picovector.cpp
@@ -214,6 +214,24 @@ mp_obj_t POLYGON_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw,
     return self;
 }
 
+mp_obj_t POLYGON_centroid(mp_obj_t self_in) {
+    _POLYGON_obj_t *self = MP_OBJ_TO_PTR2(self_in, _POLYGON_obj_t);
+
+    pretty_poly::point_t<picovector_point_type> sum(0, 0);
+
+    for(auto i = 0u; i < self->contour.count; i++) {
+        sum += self->contour.points[i];
+    }
+
+    sum /= (float)self->contour.count;
+
+    mp_obj_t tuple[2];
+    tuple[0] = mp_obj_new_int((int)(sum.x));
+    tuple[1] = mp_obj_new_int((int)(sum.y));
+
+    return mp_obj_new_tuple(2, tuple);
+}
+
 void POLYGON_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     _POLYGON_obj_t *self = MP_OBJ_TO_PTR2(self_in, _POLYGON_obj_t);
diff --git a/micropython/modules/picovector/picovector.h b/micropython/modules/picovector/picovector.h
index 2fc58ac3..a4158e88 100644
--- a/micropython/modules/picovector/picovector.h
+++ b/micropython/modules/picovector/picovector.h
@@ -10,6 +10,7 @@ extern mp_obj_t POLYGON_make_new(const mp_obj_type_t *type, size_t n_args, size_
 extern mp_obj_t REGULAR_POLYGON_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args);
 extern mp_obj_t RECTANGLE_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args);
 extern void POLYGON_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind);
+extern mp_obj_t POLYGON_centroid(mp_obj_t self_in);
 extern mp_obj_t POLYGON_getiter(mp_obj_t o_in, mp_obj_iter_buf_t *iter_buf);
 
 extern mp_obj_t POLYGON__del__(mp_obj_t self_in);