feat(lv_math): add lv_rand_set_seed api (#5013)

src/lv_init.c

@@ -87,7 +87,7 @@ static inline void lv_global_init(lv_global_t * global)
     global->style_last_custom_prop_id = (uint32_t)_LV_STYLE_LAST_BUILT_IN_PROP;
     global->area_trans_cache.angle_prev = INT32_MIN;
     global->event_last_register_id = _LV_EVENT_LAST;
-    global->math_rand_seed = 0x1234ABCD;
+    lv_rand_set_seed(0x1234ABCD);
 
 #if defined(LV_DRAW_SW_SHADOW_CACHE_SIZE) && LV_DRAW_SW_SHADOW_CACHE_SIZE > 0
     global->sw_shadow_cache.cache_size = -1;

src/misc/lv_math.c

@@ -333,6 +333,11 @@ int32_t lv_map(int32_t x, int32_t min_in, int32_t max_in, int32_t min_out, int32
     return ((x - min_in) * delta_out) / delta_in + min_out;
 }
 
+void lv_rand_set_seed(uint32_t seed)
+{
+    rand_seed = seed;
+}
+
 uint32_t lv_rand(uint32_t min, uint32_t max)
 {
     /*Algorithm "xor" from p. 4 of Marsaglia, "Xorshift RNGs"*/

src/misc/lv_math.h

@@ -125,6 +125,12 @@ int64_t lv_pow(int64_t base, int8_t exp);
  */
 int32_t lv_map(int32_t x, int32_t min_in, int32_t max_in, int32_t min_out, int32_t max_out);
 
+/**
+ * Set the seed of the pseudo random number generator
+ * @param seed a number to initialize the random generator
+ */
+void lv_rand_set_seed(uint32_t seed);
+
 /**
  * Get a pseudo random number in the given range
  * @param min   the minimum value