fix(arc): ignore hits that are outside drawn background arc (#6753)

docs/widgets/arc.rst

@@ -105,13 +105,19 @@ the object non-clickable:
    lv_obj_remove_style(arc, NULL, LV_PART_KNOB);
    lv_obj_remove_flag(arc, LV_OBJ_FLAG_CLICKABLE);
 
-Advanced hit test
------------------
+Interactive area
+----------------
 
-If the :cpp:enumerator:`LV_OBJ_FLAG_ADV_HITTEST` flag is enabled the arc can be
-clicked through in the middle. Clicks are recognized only on the ring of
-the background arc. :cpp:func:`lv_obj_set_ext_click_size` makes the sensitive
-area larger inside and outside with the given number of pixels.
+By default :cpp:enumerator:`LV_OBJ_FLAG_ADV_HITTEST` is disabled which 
+means the arc's whole area is interactive. 
+As usual :cpp:func:`lv_obj_set_ext_click_size` can be used to increase
+the sensitive area outside the arc by a specified number of pixels.
+
+If :cpp:enumerator:`LV_OBJ_FLAG_ADV_HITTEST` is enabled the arc will be sensitive only 
+in the range of start and end background angles and on the arc itself (not inside the arc). 
+In this case ``ext_click_size`` makes the sensitive area ticker both inward and outward.
+Additionally, a tolerance of :cpp:expr:`lv_dpx(50)` pixels is applied to each angle, extending the 
+hit-test range along the arc's length.
 
 Place another object to the knob
 --------------------------------

src/widgets/arc/lv_arc.c

@@ -199,6 +199,9 @@ void lv_arc_set_rotation(lv_obj_t * obj, int32_t rotation)
     LV_ASSERT_OBJ(obj, MY_CLASS);
     lv_arc_t * arc = (lv_arc_t *)obj;
 
+    /* ensure the angle is in the range [0, 360) */
+    while(rotation < 0) rotation += 360;
+    while(rotation >= 360) rotation -= 360;
     arc->rotation = rotation;
 
     lv_obj_invalidate(obj);
@@ -506,8 +509,9 @@ static void lv_arc_event(const lv_obj_class_t * class_p, lv_event_t * e)
         angle -= arc->rotation;
         angle -= arc->bg_angle_start;  /*Make the angle relative to the start angle*/
 
-        /* If we click near the bg_angle_start the angle will be close to 360° instead of a small angle */
-        if(angle < 0) angle += 360;
+        /* ensure the angle is in the range [0, 360) */
+        while(angle < 0) angle += 360;
+        while(angle >= 360) angle -= 360;
 
         const uint32_t circumference = (uint32_t)((2U * r * 314U) / 100U);  /* Equivalent to: 2r * 3.14, avoiding floats */
         const lv_value_precise_t tolerance_deg = (360 * lv_dpx(50U)) / circumference;
@@ -655,6 +659,25 @@ static void lv_arc_event(const lv_obj_class_t * class_p, lv_event_t * e)
             return;
         }
 
+        /*Calculate the angle of the pressed point*/
+        lv_value_precise_t angle = lv_atan2(info->point->y - p.y, info->point->x - p.x);
+        angle -= arc->rotation;
+        angle -= arc->bg_angle_start;  /*Make the angle relative to the start angle*/
+
+        /* ensure the angle is in the range [0, 360) */
+        while(angle < 0) angle += 360;
+        while(angle >= 360) angle -= 360;
+
+        const uint32_t circumference = (uint32_t)((2U * r * 314U) / 100U);  /* Equivalent to: 2r * 3.14, avoiding floats */
+        const lv_value_precise_t tolerance_deg = (360 * lv_dpx(50U)) / circumference;
+
+        /* Check if the angle is outside the drawn background arc */
+        const bool is_angle_within_bg_bounds = lv_arc_angle_within_bg_bounds(obj, angle, tolerance_deg);
+        if(!is_angle_within_bg_bounds) {
+            info->res = false;
+            return;
+        }
+
         /*Valid if no clicked outside*/
         lv_area_increase(&a, w + ext_click_area * 2, w + ext_click_area * 2);
         info->res = lv_area_is_point_on(&a, info->point, LV_RADIUS_CIRCLE);
@@ -941,7 +964,10 @@ static bool lv_arc_angle_within_bg_bounds(lv_obj_t * obj, const lv_value_precise
     lv_arc_t * arc = (lv_arc_t *)obj;
 
     lv_value_precise_t bounds_angle = arc->bg_angle_end - arc->bg_angle_start;
-    if(bounds_angle < 0) bounds_angle += 360;
+
+    /* ensure the angle is in the range [0, 360) */
+    while(bounds_angle < 0) bounds_angle += 360;
+    while(bounds_angle >= 360) bounds_angle -= 360;
 
     /* Angle is in the bounds */
     if(angle <= bounds_angle) {

tests/src/test_cases/widgets/test_arc.c

@@ -18,9 +18,12 @@ void test_arc_angles_when_reversed(void);
 
 static lv_obj_t * active_screen = NULL;
 static lv_obj_t * arc = NULL;
+static lv_obj_t * arc2 = NULL;
 static uint32_t event_cnt;
+static uint32_t event_cnt2;
 
 static void dummy_event_cb(lv_event_t * e);
+static void dummy_event_cb2(lv_event_t * e);
 
 void setUp(void)
 {
@@ -232,10 +235,71 @@ void test_arc_click_sustained_from_start_to_end_does_not_set_value_to_max(void)
     TEST_ASSERT_EQUAL_SCREENSHOT("widgets/arc_3.png");
 }
 
+void test_two_overlapping_arcs_can_be_interacted_independently(void)
+{
+    arc = lv_arc_create(lv_screen_active());
+    arc2 = lv_arc_create(lv_screen_active());
+
+    lv_arc_set_value(arc, 0);
+    lv_arc_set_value(arc2, 0);
+    lv_obj_set_size(arc, 100, 100);
+    lv_obj_set_size(arc2, 100, 100);
+    lv_arc_set_bg_angles(arc, 20, 160);
+    lv_arc_set_bg_angles(arc2, 200, 340);
+    lv_obj_add_flag(arc, LV_OBJ_FLAG_ADV_HITTEST);
+    lv_obj_add_flag(arc2, LV_OBJ_FLAG_ADV_HITTEST);
+    lv_arc_set_value(arc, 10);
+    lv_arc_set_value(arc2, 10);
+    lv_arc_set_rotation(arc, 355);
+    lv_arc_set_rotation(arc2, 355);
+    lv_obj_center(arc);
+    lv_obj_center(arc2);
+
+    // Add event callback to both arcs
+    lv_obj_add_event_cb(arc, dummy_event_cb, LV_EVENT_PRESSED, NULL);
+    lv_obj_add_event_cb(arc2, dummy_event_cb2, LV_EVENT_PRESSED, NULL);
+
+    // Reset event counters
+    event_cnt = 0;
+    event_cnt2 = 0;
+
+    // Click on the position of the first arc (center)
+    lv_test_mouse_move_to(400, 195);
+    lv_test_mouse_press();
+    lv_test_indev_wait(500);
+    lv_test_mouse_release();
+    lv_test_indev_wait(50);
+
+    // Verify that the event callback was called for the first arc
+    TEST_ASSERT_EQUAL_UINT32(0, event_cnt);
+    TEST_ASSERT_EQUAL_UINT32(1, event_cnt2);
+
+    // click on the position of the second arc (center)
+    lv_test_mouse_move_to(400, 285);
+    lv_test_mouse_press();
+    lv_test_indev_wait(500);
+    lv_test_mouse_release();
+    lv_test_indev_wait(50);
+
+    // Verify that the event callback was called for the second arc
+    TEST_ASSERT_EQUAL_UINT32(1, event_cnt);
+    TEST_ASSERT_EQUAL_UINT32(1, event_cnt2);
+
+    // Verify that the screen remains as expected after the interactions
+    TEST_ASSERT_EQUAL_SCREENSHOT("widgets/overlapping_arcs_test.png");
+}
+
+
 static void dummy_event_cb(lv_event_t * e)
 {
     LV_UNUSED(e);
     event_cnt++;
 }
 
+static void dummy_event_cb2(lv_event_t * e)
+{
+    LV_UNUSED(e);
+    event_cnt2++;
+}
+
 #endif