fix(scroll): send LV_EVENT_SCROLL_BEGIN/END with no animation too

docs/overview/scroll.md

@@ -55,8 +55,8 @@ or on the object's or any parent's main part to make a scrollbar inherit the bas
 
 ### Events
 The following events are related to scrolling:
-- `LV_EVENT_SCROLL_BEGIN` Scrolling begins
+- `LV_EVENT_SCROLL_BEGIN` Scrolling begins. The event parameter is `NULL` or an `lv_anim_t *` with a scroll animation descriptor that can be modified if required.
-- `LV_EVENT_SCROLL_END` Scrolling ends
+- `LV_EVENT_SCROLL_END` Scrolling ends.
 - `LV_EVENT_SCROLL` Scroll happened. Triggered on every position change.
 Scroll events
 

src/core/lv_event.h

@@ -41,7 +41,7 @@ typedef enum {
     LV_EVENT_LONG_PRESSED_REPEAT, /**< Called after `long_press_time` in every `long_press_repeat_time` ms.  Not called if scrolled.*/
     LV_EVENT_CLICKED,             /**< Called on release if not scrolled (regardless to long press)*/
     LV_EVENT_RELEASED,            /**< Called in every cases when the object has been released*/
-    LV_EVENT_SCROLL_BEGIN,        /**< Scrolling begins*/
+    LV_EVENT_SCROLL_BEGIN,        /**< Scrolling begins. The event parameter is a pointer to the animation of the scroll. Can be modified*/
     LV_EVENT_SCROLL_END,          /**< Scrolling ends*/
     LV_EVENT_SCROLL,              /**< Scrolling*/
     LV_EVENT_GESTURE,             /**< A gesture is detected. Get the gesture with `lv_indev_get_gesture_dir(lv_indev_get_act());` */

src/core/lv_obj_scroll.c

@@ -31,7 +31,7 @@
 /**********************
  *  STATIC PROTOTYPES
  **********************/
-static void scroll_by_raw(lv_obj_t * obj, lv_coord_t x, lv_coord_t y);
+static lv_res_t scroll_by_raw(lv_obj_t * obj, lv_coord_t x, lv_coord_t y);
 static void scroll_x_anim(void * obj, int32_t v);
 static void scroll_y_anim(void * obj, int32_t v);
 static void scroll_anim_ready_cb(lv_anim_t * a);
@@ -345,15 +345,19 @@ void lv_obj_scroll_by(lv_obj_t * obj, lv_coord_t dx, lv_coord_t dy, lv_anim_enab
     }
     else {
         /*Remove pending animations*/
-        bool y_del = lv_anim_del(obj, scroll_y_anim);
+        lv_anim_del(obj, scroll_y_anim);
-        bool x_del = lv_anim_del(obj, scroll_x_anim);
+        lv_anim_del(obj, scroll_x_anim);
-        scroll_by_raw(obj, dx, dy);
+
-        if(y_del || x_del) {
         lv_res_t res;
+        res = lv_event_send(obj, LV_EVENT_SCROLL_BEGIN, NULL);
+        if(res != LV_RES_OK) return;
+
+        res = scroll_by_raw(obj, dx, dy);
+        if(res != LV_RES_OK) return;
+
         res = lv_event_send(obj, LV_EVENT_SCROLL_END, NULL);
         if(res != LV_RES_OK) return;
     }
-    }
 }
 
 void lv_obj_scroll_to(lv_obj_t * obj, lv_coord_t x, lv_coord_t y, lv_anim_enable_t anim_en)
@@ -648,9 +652,9 @@ void lv_obj_readjust_scroll(lv_obj_t * obj, lv_anim_enable_t anim_en)
  *   STATIC FUNCTIONS
  **********************/
 
-static void scroll_by_raw(lv_obj_t * obj, lv_coord_t x, lv_coord_t y)
+static lv_res_t scroll_by_raw(lv_obj_t * obj, lv_coord_t x, lv_coord_t y)
 {
-    if(x == 0 && y == 0) return;
+    if(x == 0 && y == 0) return LV_RES_OK;
 
     lv_obj_allocate_spec_attr(obj);
 
@@ -659,8 +663,9 @@ static void scroll_by_raw(lv_obj_t * obj, lv_coord_t x, lv_coord_t y)
 
     lv_obj_move_children_by(obj, x, y, true);
     lv_res_t res = lv_event_send(obj, LV_EVENT_SCROLL, NULL);
-    if(res != LV_RES_OK) return;
+    if(res != LV_RES_OK) return res;
     lv_obj_invalidate(obj);
+    return LV_RES_OK;
 }
 
 static void scroll_x_anim(void * obj, int32_t v)