init Files

libraries/lvgl/examples/widgets/arc/index.rst

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+
+Simple Arc
+----------
+
+.. lv_example:: widgets/arc/lv_example_arc_1
+  :language: c
+  :description: A simple example to demonstrate the use of an arc.
+
+Loader with Arc
+---------------
+
+.. lv_example:: widgets/arc/lv_example_arc_2
+  :language: c
+

libraries/lvgl/examples/widgets/arc/lv_example_arc_1.c

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+#include "../../lv_examples.h"
+
+#if LV_USE_ARC && LV_BUILD_EXAMPLES
+
+static void value_changed_event_cb(lv_event_t * e);
+
+void lv_example_arc_1(void)
+{
+    lv_obj_t * label = lv_label_create(lv_screen_active());
+
+    /*Create an Arc*/
+    lv_obj_t * arc = lv_arc_create(lv_screen_active());
+    lv_obj_set_size(arc, 150, 150);
+    lv_arc_set_rotation(arc, 135);
+    lv_arc_set_bg_angles(arc, 0, 270);
+    lv_arc_set_value(arc, 10);
+    lv_obj_center(arc);
+    lv_obj_add_event_cb(arc, value_changed_event_cb, LV_EVENT_VALUE_CHANGED, label);
+
+    /*Manually update the label for the first time*/
+    lv_obj_send_event(arc, LV_EVENT_VALUE_CHANGED, NULL);
+}
+
+static void value_changed_event_cb(lv_event_t * e)
+{
+    lv_obj_t * arc = lv_event_get_target(e);
+    lv_obj_t * label = lv_event_get_user_data(e);
+
+    lv_label_set_text_fmt(label, "%" LV_PRId32 "%%", lv_arc_get_value(arc));
+
+    /*Rotate the label to the current position of the arc*/
+    lv_arc_rotate_obj_to_angle(arc, label, 25);
+}
+
+#endif

libraries/lvgl/examples/widgets/arc/lv_example_arc_2.c

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+#include "../../lv_examples.h"
+
+#if LV_USE_ARC && LV_BUILD_EXAMPLES
+
+static void set_angle(void * obj, int32_t v)
+{
+    lv_arc_set_value(obj, v);
+}
+
+/**
+ * Create an arc which acts as a loader.
+ */
+void lv_example_arc_2(void)
+{
+    /*Create an Arc*/
+    lv_obj_t * arc = lv_arc_create(lv_screen_active());
+    lv_arc_set_rotation(arc, 270);
+    lv_arc_set_bg_angles(arc, 0, 360);
+    lv_obj_remove_style(arc, NULL, LV_PART_KNOB);   /*Be sure the knob is not displayed*/
+    lv_obj_remove_flag(arc, LV_OBJ_FLAG_CLICKABLE);  /*To not allow adjusting by click*/
+    lv_obj_center(arc);
+
+    lv_anim_t a;
+    lv_anim_init(&a);
+    lv_anim_set_var(&a, arc);
+    lv_anim_set_exec_cb(&a, set_angle);
+    lv_anim_set_duration(&a, 1000);
+    lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);    /*Just for the demo*/
+    lv_anim_set_repeat_delay(&a, 500);
+    lv_anim_set_values(&a, 0, 100);
+    lv_anim_start(&a);
+
+}
+
+#endif