further improve arc invalidation

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 1
+#define MASK_AREA_DEBUG 0
 
 /**********************
  *      TYPEDEFS

src/lv_draw/lv_draw_arc.c

@@ -298,7 +298,7 @@ static void draw_quarter_2(quarter_draw_dsc_t * q)
     else if((q->start_quarter == q->end_quarter && q->start_quarter != 2 && q->end_angle < q->start_angle) ||
             (q->start_quarter == 0 && q->end_quarter == 3) ||
             (q->start_quarter == 1 && q->end_quarter == 3) ||
-            (q->start_quarter == 3 && q->end_quarter == 1)) {
+            (q->start_quarter == 1 && q->end_quarter == 0)) {
         /*Arc crosses here*/
         quarter_area.x1 = q->center_x - q->radius;
         quarter_area.y1 = q->center_y - q->radius;
@@ -365,8 +365,6 @@ static void draw_quarter_3(quarter_draw_dsc_t * q)
 }
 
 
-
-
 static void get_rounded_area(int16_t angle, lv_coord_t radius, uint8_t tickness, lv_area_t * res_area)
 {
     const uint8_t ps = 8;

src/lv_objx/lv_arc.c

@@ -130,9 +130,24 @@ void lv_arc_set_start_angle(lv_obj_t * arc, int16_t start)
 
     if(start > 360) start -= 360;
 
-    ext->angle_start = start;
+    /*Too large move, the whole arc need to be invalidated anyway*/
+    if(LV_MATH_ABS(start - ext->angle_start) >= 180) {
+        lv_obj_invalidate(arc);
+    }
+    /*Only a smaller incremental move*/
+    else if(ext->angle_start > ext->angle_end && start > ext->angle_end) {
+        inv_arc_area(arc, LV_MATH_MIN(ext->angle_start, start), LV_MATH_MAX(ext->angle_start, start));
+    }
+    /*Only a smaller incremental move*/
+    else  if(ext->angle_start < ext->angle_end && start < ext->angle_end) {
+        inv_arc_area(arc, LV_MATH_MIN(ext->angle_start, start), LV_MATH_MAX(ext->angle_start, start));
+    }
+    /*Crossing the start angle makes the whole arc change*/
+    else {
+        lv_obj_invalidate(arc);
+    }
 
-    lv_obj_invalidate(arc);
+    ext->angle_start = start;
 }
 
 /**
@@ -148,9 +163,24 @@ void lv_arc_set_end_angle(lv_obj_t * arc, int16_t end)
 
     if(end > 360) end -= 360;
 
-    ext->angle_end= end;
+    /*Too large move, the whole arc need to be invalidated anyway*/
+    if(LV_MATH_ABS(end - ext->angle_end) >= 180) {
+        lv_obj_invalidate(arc);
+    }
+    /*Only a smaller incremental move*/
+    else if(ext->angle_end > ext->angle_start && end > ext->angle_start ) {
+        inv_arc_area(arc, LV_MATH_MIN(ext->angle_end, end), LV_MATH_MAX(ext->angle_end, end));
+    }
+    /*Only a smaller incremental move*/
+    else  if(ext->angle_end < ext->angle_start && end < ext->angle_start ) {
+        inv_arc_area(arc, LV_MATH_MIN(ext->angle_end, end), LV_MATH_MAX(ext->angle_end, end));
+    }
+    /*Crossing the end angle makes the whole arc change*/
+    else {
+        lv_obj_invalidate(arc);
+    }
 
-    lv_obj_invalidate(arc);
+    ext->angle_end= end;
 }
 
 
@@ -327,7 +357,7 @@ static void inv_arc_area(lv_obj_t * arc, uint16_t start_angle, uint16_t end_angl
 
     lv_area_t inv_area;
 
-    if(start_quarter == end_quarter) {
+    if(start_quarter == end_quarter && start_angle <= end_angle) {
         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);