perf(snapshot): render from the top object when taking snapshot. (#8424)

Signed-off-by: yushuailong1 <yushuailong1@xiaomi.com>

src/core/lv_refr.c

@@ -44,7 +44,6 @@ static void refr_invalid_areas(void);
 static void refr_sync_areas(void);
 static void refr_area(const lv_area_t * area_p, int32_t y_offset);
 static void refr_configured_layer(lv_layer_t * layer);
-static lv_obj_t * lv_refr_get_top_obj(const lv_area_t * area_p, lv_obj_t * obj);
 static void refr_obj_and_children(lv_layer_t * layer, lv_obj_t * top_obj);
 static void refr_obj(lv_layer_t * layer, lv_obj_t * obj);
 static uint32_t get_max_row(lv_display_t * disp, int32_t area_w, int32_t area_h);
@@ -432,6 +431,49 @@ refr_finish:
     LV_PROFILER_REFR_END;
 }
 
+/**
+ * Search the most top object which fully covers an area
+ * @param area_p pointer to an area
+ * @param obj the first object to start the searching (typically a screen)
+ * @return
+ */
+lv_obj_t * lv_refr_get_top_obj(const lv_area_t * area_p, lv_obj_t * obj)
+{
+    lv_obj_t * found_p = NULL;
+
+    if(lv_area_is_in(area_p, &obj->coords, 0) == false) return NULL;
+    if(lv_obj_has_flag(obj, LV_OBJ_FLAG_HIDDEN)) return NULL;
+    if(lv_obj_get_layer_type(obj) != LV_LAYER_TYPE_NONE) return NULL;
+    if(lv_obj_get_style_opa(obj, LV_PART_MAIN) < LV_OPA_MAX) return NULL;
+
+    /*If this object is fully cover the draw area then check the children too*/
+    lv_cover_check_info_t info;
+    info.res = LV_COVER_RES_COVER;
+    info.area = area_p;
+    lv_obj_send_event(obj, LV_EVENT_COVER_CHECK, &info);
+    if(info.res == LV_COVER_RES_MASKED) return NULL;
+
+    int32_t i;
+    int32_t child_cnt = lv_obj_get_child_count(obj);
+    for(i = child_cnt - 1; i >= 0; i--) {
+        lv_obj_t * child = obj->spec_attr->children[i];
+        found_p = lv_refr_get_top_obj(area_p, child);
+
+        /*If a children is ok then break*/
+        if(found_p != NULL) {
+            break;
+        }
+    }
+
+    /*If no better children use this object*/
+    if(found_p == NULL && info.res == LV_COVER_RES_COVER) {
+        found_p = obj;
+    }
+
+    return found_p;
+}
+
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/
@@ -902,48 +944,6 @@ static void refr_configured_layer(lv_layer_t * layer)
     LV_PROFILER_REFR_END;
 }
 
-/**
- * Search the most top object which fully covers an area
- * @param area_p pointer to an area
- * @param obj the first object to start the searching (typically a screen)
- * @return
- */
-static lv_obj_t * lv_refr_get_top_obj(const lv_area_t * area_p, lv_obj_t * obj)
-{
-    lv_obj_t * found_p = NULL;
-
-    if(lv_area_is_in(area_p, &obj->coords, 0) == false) return NULL;
-    if(lv_obj_has_flag(obj, LV_OBJ_FLAG_HIDDEN)) return NULL;
-    if(lv_obj_get_layer_type(obj) != LV_LAYER_TYPE_NONE) return NULL;
-    if(lv_obj_get_style_opa(obj, LV_PART_MAIN) < LV_OPA_MAX) return NULL;
-
-    /*If this object is fully cover the draw area then check the children too*/
-    lv_cover_check_info_t info;
-    info.res = LV_COVER_RES_COVER;
-    info.area = area_p;
-    lv_obj_send_event(obj, LV_EVENT_COVER_CHECK, &info);
-    if(info.res == LV_COVER_RES_MASKED) return NULL;
-
-    int32_t i;
-    int32_t child_cnt = lv_obj_get_child_count(obj);
-    for(i = child_cnt - 1; i >= 0; i--) {
-        lv_obj_t * child = obj->spec_attr->children[i];
-        found_p = lv_refr_get_top_obj(area_p, child);
-
-        /*If a children is ok then break*/
-        if(found_p != NULL) {
-            break;
-        }
-    }
-
-    /*If no better children use this object*/
-    if(found_p == NULL && info.res == LV_COVER_RES_COVER) {
-        found_p = obj;
-    }
-
-    return found_p;
-}
-
 /**
  * Make the refreshing from an object. Draw all its children and the youngers too.
  * @param top_p pointer to an objects. Start the drawing from it.

src/core/lv_refr_private.h

@@ -58,6 +58,14 @@ lv_display_t * lv_refr_get_disp_refreshing(void);
  */
 void lv_refr_set_disp_refreshing(lv_display_t * disp);
 
+/**
+ * Search the most top object which fully covers an area
+ * @param area_p pointer to an area
+ * @param obj the first object to start the searching (typically a screen)
+ * @return
+ */
+lv_obj_t * lv_refr_get_top_obj(const lv_area_t * area_p, lv_obj_t * obj);
+
 /**********************
  *      MACROS
  **********************/

src/others/snapshot/lv_snapshot.c

@@ -98,9 +98,6 @@ lv_result_t lv_snapshot_take_to_draw_buf(lv_obj_t * obj, lv_color_format_t cf, l
     res = lv_snapshot_reshape_draw_buf(obj, draw_buf);
     if(res != LV_RESULT_OK) return res;
 
-    /* clear draw buffer*/
-    lv_draw_buf_clear(draw_buf, NULL);
-
     lv_area_t snapshot_area;
     int32_t w = draw_buf->header.w;
     int32_t h = draw_buf->header.h;
@@ -108,6 +105,13 @@ lv_result_t lv_snapshot_take_to_draw_buf(lv_obj_t * obj, lv_color_format_t cf, l
     lv_obj_get_coords(obj, &snapshot_area);
     lv_area_increase(&snapshot_area, ext_size, ext_size);
 
+    lv_obj_t * top_obj = lv_refr_get_top_obj(&snapshot_area, obj);
+    if(top_obj == NULL) {
+        /* Clear draw buffer when no top object*/
+        lv_draw_buf_clear(draw_buf, NULL);
+        top_obj = obj;
+    }
+
     lv_layer_t layer;
     lv_layer_init(&layer);
 
@@ -126,7 +130,7 @@ lv_result_t lv_snapshot_take_to_draw_buf(lv_obj_t * obj, lv_color_format_t cf, l
     disp_new->layer_head = &layer;
 
     lv_refr_set_disp_refreshing(disp_new);
-    lv_obj_redraw(&layer, obj);
+    lv_obj_redraw(&layer, top_obj);
 
     while(layer.draw_task_head) {
         lv_draw_dispatch_wait_for_request();