Add twin_sincos function to refactor sin/cos usage

As several applications need the sine and cosine of the same angle, I
replace all occurrences of `twin_sin` and `twin_cos` with the shortcut
`twin_sincos`, including the code in the files `src/path.c` and
`src/matrix.c`.

Author: ndsl7109256

include/twin.h

@@ -736,6 +736,8 @@ void twin_path_rmove(twin_path_t *path, twin_fixed_t x, twin_fixed_t y);
 
 void twin_path_draw(twin_path_t *path, twin_fixed_t x, twin_fixed_t y);
 
+void twin_path_draw_polar(twin_path_t *path, twin_angle_t deg);
+
 void twin_path_rdraw(twin_path_t *path, twin_fixed_t x, twin_fixed_t y);
 
 void twin_path_circle(twin_path_t *path,
@@ -1042,6 +1044,8 @@ twin_fixed_t twin_cos(twin_angle_t a);
 
 twin_fixed_t twin_tan(twin_angle_t a);
 
+void twin_sincos(twin_angle_t a, twin_fixed_t *sin, twin_fixed_t *cos);
+
 /*
  * widget.c
  */

src/matrix.c

@@ -100,8 +100,8 @@ twin_point_t _twin_matrix_expand(twin_matrix_t *matrix)
 void twin_matrix_rotate(twin_matrix_t *m, twin_angle_t a)
 {
     twin_matrix_t t;
-    twin_fixed_t c = twin_cos(a);
-    twin_fixed_t s = twin_sin(a);
+    twin_fixed_t c, s;
+    twin_sincos(a, &c, &s);
 
     t.m[0][0] = c;
     t.m[0][1] = s;

src/path.c

@@ -134,6 +134,13 @@ void twin_path_draw(twin_path_t *path, twin_fixed_t x, twin_fixed_t y)
                      _twin_matrix_y(&path->state.matrix, x, y));
 }
 
+void twin_path_draw_polar(twin_path_t *path, twin_angle_t deg)
+{
+    twin_fixed_t s, c;
+    twin_sincos(deg, &s, &c);
+    twin_path_draw(path, c, s);
+}
+
 void twin_path_rdraw(twin_path_t *path, twin_fixed_t dx, twin_fixed_t dy)
 {
     twin_spoint_t here = _twin_path_current_spoint(path);
@@ -218,14 +225,13 @@ void twin_path_arc(twin_path_t *path,
     twin_angle_t last = (start + extent - inc + epsilon) & ~(step - 1);
 
     if (first != start)
-        twin_path_draw(path, twin_cos(start), twin_sin(start));
+        twin_path_draw_polar(path, start);
 
     for (twin_angle_t a = first; a != last; a += inc)
-        twin_path_draw(path, twin_cos(a), twin_sin(a));
+        twin_path_draw_polar(path, a);
 
     if (last != start + extent)
-        twin_path_draw(path, twin_cos(start + extent),
-                       twin_sin(start + extent));
+        twin_path_draw_polar(path, start + extent);
 
     twin_path_set_matrix(path, save);
 }

src/trig.c

@@ -62,3 +62,10 @@ twin_fixed_t twin_tan(twin_angle_t a)
         return 0;
     return ((s << 15) / c) << 1;
 }
+
+void twin_sincos(twin_angle_t a, twin_fixed_t *sin, twin_fixed_t *cos)
+{
+    *sin = twin_sin(a);
+    *cos = twin_cos(a);
+}
+