diff --git a/src/lv_core/lv_refr.c b/src/lv_core/lv_refr.c
index c017491d6..c0932aefa 100644
--- a/src/lv_core/lv_refr.c
+++ b/src/lv_core/lv_refr.c
@@ -24,7 +24,7 @@
  *      DEFINES
  *********************/
 /* Draw translucent random colored areas on the invalidated (redrawn) areas*/
-#define MASK_AREA_DEBUG 0
+#define MASK_AREA_DEBUG 1
 
 /**********************
  *      TYPEDEFS
diff --git a/src/lv_objx/lv_arc.c b/src/lv_objx/lv_arc.c
index 1c8df09c5..5ba4758de 100644
--- a/src/lv_objx/lv_arc.c
+++ b/src/lv_objx/lv_arc.c
@@ -28,6 +28,7 @@
  **********************/
 static lv_design_res_t lv_arc_design(lv_obj_t * arc, const lv_area_t * clip_area, lv_design_mode_t mode);
 static lv_res_t lv_arc_signal(lv_obj_t * arc, lv_signal_t sign, void * param);
+static void inv_arc_area(lv_obj_t * arc, uint16_t start_angle, uint16_t end_angle);
 
 /**********************
  *  STATIC VARIABLES
@@ -166,13 +167,14 @@ void lv_arc_set_angles(lv_obj_t * arc, uint16_t start, uint16_t end)
     lv_arc_ext_t * ext = lv_obj_get_ext_attr(arc);
 
     if(end > 360) end -= 360;
-
     if(start > 360) start -= 360;
 
+    inv_arc_area(arc, ext->angle_start, ext->angle_end);
+
     ext->angle_start = start;
     ext->angle_end = end;
 
-    lv_obj_invalidate(arc);
+    inv_arc_area(arc, ext->angle_start, ext->angle_end);
 }
 
 /**
@@ -317,27 +319,80 @@ static void inv_arc_area(lv_obj_t * arc, uint16_t start_angle, uint16_t end_angl
 {
     uint8_t start_quarter = start_angle / 90;
     uint8_t end_quarter = end_angle / 90;
-    lv_coord_t r       = (LV_MATH_MIN(lv_obj_get_width(arc), lv_obj_get_height(arc))) / 2;
     lv_coord_t x       = arc->coords.x1 + lv_obj_get_width(arc) / 2;
     lv_coord_t y       = arc->coords.y1 + lv_obj_get_height(arc) / 2;
-    const lv_style_t style = lv_arc_get_style(arc, LV_ARC_STYLE_MAIN);
-    lv_coord_t w       = style->line.width;
+    lv_coord_t rout       = (LV_MATH_MIN(lv_obj_get_width(arc), lv_obj_get_height(arc))) / 2;
+    const lv_style_t * style = lv_arc_get_style(arc, LV_ARC_STYLE_MAIN);
+    lv_coord_t rin       = rout - style->line.width;
+
     lv_area_t inv_area;
 
     if(start_quarter == end_quarter) {
-        if(start_quarter == 3) {
-            /*Small arc here*/
-            inv_area.x1 = x + ((lv_trigo_sin(start_angle + 90) * (r - q->width)) >> LV_TRIGO_SHIFT);
-            inv_area.y1 = y + ((lv_trigo_sin(start_angle) * (r)) >> LV_TRIGO_SHIFT);
+        if(start_quarter == 0) {
+            inv_area.y1 = y + ((lv_trigo_sin(start_angle) * rin) >> LV_TRIGO_SHIFT);
+            inv_area.x2 = x + ((lv_trigo_sin(start_angle + 90) * rout) >> LV_TRIGO_SHIFT);
 
-            inv_area.x2 = x + ((lv_trigo_sin(end_angle + 90) * (r)) >> LV_TRIGO_SHIFT);
-            inv_area.y2 = y + ((lv_trigo_sin(end_angle) * (r - q->width)) >> LV_TRIGO_SHIFT);
+            inv_area.y2 = y + ((lv_trigo_sin(end_angle) * rout) >> LV_TRIGO_SHIFT);
+            inv_area.x1 = x + ((lv_trigo_sin(end_angle + 90) * rin) >> LV_TRIGO_SHIFT);
 
-                    bool ok = lv_area_intersect(&quarter_area, &quarter_area, q->clip_area);
-                    if(ok) lv_draw_rect(q->draw_area, &quarter_area, q->style, q->opa_scale);
+            lv_obj_invalidate_area(arc, &inv_area);
         }
+        else if(start_quarter == 1) {
+            inv_area.y2 = y + ((lv_trigo_sin(start_angle) * rout) >> LV_TRIGO_SHIFT);
+            inv_area.x2 = x + ((lv_trigo_sin(start_angle + 90) * rin) >> LV_TRIGO_SHIFT);
+
+            inv_area.y1 = y + ((lv_trigo_sin(end_angle) * rin) >> LV_TRIGO_SHIFT);
+            inv_area.x1 = x + ((lv_trigo_sin(end_angle + 90) * rout) >> LV_TRIGO_SHIFT);
+
+            lv_obj_invalidate_area(arc, &inv_area);
+        }
+        else if(start_quarter == 2) {
+            inv_area.x1 = x + ((lv_trigo_sin(start_angle + 90) * rout) >> LV_TRIGO_SHIFT);
+            inv_area.y2 = y + ((lv_trigo_sin(start_angle) * rin) >> LV_TRIGO_SHIFT);
+
+            inv_area.y1 = y + ((lv_trigo_sin(end_angle) * rout) >> LV_TRIGO_SHIFT);
+            inv_area.x2 = x + ((lv_trigo_sin(end_angle + 90) * rin) >> LV_TRIGO_SHIFT);
+
+            lv_obj_invalidate_area(arc, &inv_area);
+        }
+        else if(start_quarter == 3) {
+            /*Small arc here*/
+            inv_area.x1 = x + ((lv_trigo_sin(start_angle + 90) * rin) >> LV_TRIGO_SHIFT);
+            inv_area.y1 = y + ((lv_trigo_sin(start_angle) * rout) >> LV_TRIGO_SHIFT);
+
+            inv_area.x2 = x + ((lv_trigo_sin(end_angle + 90) * rout) >> LV_TRIGO_SHIFT);
+            inv_area.y2 = y + ((lv_trigo_sin(end_angle) * rin) >> LV_TRIGO_SHIFT);
+
+            lv_obj_invalidate_area(arc, &inv_area);
+        }
+
+    } else if(start_quarter == 0 && end_quarter == 1) {
+        inv_area.x1 = x + ((lv_trigo_sin(end_angle + 90) * rout) >> LV_TRIGO_SHIFT);
+        inv_area.y1 = y + ((LV_MATH_MIN(lv_trigo_sin(end_angle), lv_trigo_sin(start_angle))  * rin) >> LV_TRIGO_SHIFT);
+        inv_area.x2 = x + ((lv_trigo_sin(start_angle + 90) * rout) >> LV_TRIGO_SHIFT);
+        inv_area.y2 = y + rout;
+        lv_obj_invalidate_area(arc, &inv_area);
+    } else if(start_quarter == 1 && end_quarter == 2) {
+        inv_area.x1 = x - rout;
+        inv_area.y1 = y + ((lv_trigo_sin(end_angle) * rout) >> LV_TRIGO_SHIFT);
+        inv_area.x2 = x + ((LV_MATH_MAX(lv_trigo_sin(start_angle + 90) , lv_trigo_sin(end_angle + 90)) * rin) >> LV_TRIGO_SHIFT);
+        inv_area.y2 = y + ((lv_trigo_sin(start_angle) * rout) >> LV_TRIGO_SHIFT);
+        lv_obj_invalidate_area(arc, &inv_area);
+    }  else if(start_quarter == 2 && end_quarter == 3) {
+        inv_area.x1 = x + ((lv_trigo_sin(start_angle + 90) * rout) >> LV_TRIGO_SHIFT);
+        inv_area.y1 = y - rout;
+        inv_area.x2 = x + ((lv_trigo_sin(end_angle + 90) * rout) >> LV_TRIGO_SHIFT);
+        inv_area.y2 = y + (LV_MATH_MAX(lv_trigo_sin(end_angle) * rin, lv_trigo_sin(start_angle) * rin) >> LV_TRIGO_SHIFT);
+        lv_obj_invalidate_area(arc, &inv_area);
+    } else if(start_quarter == 3 && end_quarter == 0) {
+        inv_area.x1 = x + ((LV_MATH_MIN(lv_trigo_sin(end_angle + 90), lv_trigo_sin(start_angle + 90)) * rin) >> LV_TRIGO_SHIFT);
+        inv_area.y1 = y + ((lv_trigo_sin(start_angle) * rout) >> LV_TRIGO_SHIFT);
+        inv_area.x2 = x + rout;
+        inv_area.y2 = y + ((lv_trigo_sin(end_angle) * rout) >> LV_TRIGO_SHIFT);
+
+        lv_obj_invalidate_area(arc, &inv_area);
+    } else {
+        lv_obj_invalidate(arc);
     }
-
 }
-
 #endif
diff --git a/src/lv_objx/lv_preload.c b/src/lv_objx/lv_preload.c
index fade599ed..005d82c02 100644
--- a/src/lv_objx/lv_preload.c
+++ b/src/lv_objx/lv_preload.c
@@ -87,7 +87,7 @@ lv_obj_t * lv_preload_create(lv_obj_t * par, const lv_obj_t * copy)
     ext->arc_length = LV_PRELOAD_DEF_ARC_LENGTH;
     ext->anim_type  = LV_PRELOAD_DEF_ANIM;
     ext->anim_dir   = LV_PRELOAD_DIR_FORWARD;
-    ext->time = LV_PRELOAD_DEF_SPIN_TIME * 5;
+    ext->time = LV_PRELOAD_DEF_SPIN_TIME * 10;
 
     /*The signal and design functions are not copied so set them here*/
     lv_obj_set_signal_cb(new_preload, lv_preload_signal);