From 451eddb1237a7b90c5d6c483132e1878ea0c2db0 Mon Sep 17 00:00:00 2001
From: Gabor Kiss-Vamosi <kisvegabor@gmail.com>
Date: Thu, 8 Sep 2022 23:55:00 +0200
Subject: [PATCH] example(event): simplify lv_example_event_4

---
 examples/event/index.rst            |  5 ++
 examples/event/lv_example_event_4.c | 76 +++++++++++++----------------
 2 files changed, 38 insertions(+), 43 deletions(-)

diff --git a/examples/event/index.rst b/examples/event/index.rst
index a556ac8ce..b47635315 100644
--- a/examples/event/index.rst
+++ b/examples/event/index.rst
@@ -16,4 +16,9 @@ Event bubbling
 .. lv_example:: event/lv_example_event_3
   :language: c
 
+Draw event
+""""""""""""""""""""""""
+.. lv_example:: event/lv_example_event_4
+  :language: c
+
 
diff --git a/examples/event/lv_example_event_4.c b/examples/event/lv_example_event_4.c
index 7d459b81d..21a6ba746 100644
--- a/examples/event/lv_example_event_4.c
+++ b/examples/event/lv_example_event_4.c
@@ -2,65 +2,55 @@
 
 #if LV_BUILD_EXAMPLES
 
-static int n = 3;
-static lv_obj_t * label = NULL;
+static uint32_t size = 0;
+static bool size_dec = false;
 
 static void timer_cb(lv_timer_t * timer)
 {
-    if(n < 3 || n > 32) {
-        n = 3;
-    }
-    else {
-        static uint32_t old_tick = 0;
-        uint32_t tick = lv_tick_get();
-        if(!old_tick) {
-            old_tick = tick;
-        }
-        if(tick - old_tick > 3000) {
-            n++;
-            lv_label_set_text_fmt(label, "%d sides", n);
-            old_tick = tick;
-        }
-    }
     lv_obj_invalidate(timer->user_data);
+    if(size_dec) size--;
+    else size++;
+
+    if(size == 50) size_dec = true;
+    else if(size == 0) size_dec = false;
 }
 
 static void event_cb(lv_event_t * e)
 {
-    /*The original target of the event. Can be the buttons or the container*/
-    lv_draw_ctx_t * draw_ctx = lv_event_get_draw_ctx(e);
-    lv_draw_rect_dsc_t draw_dsc;
-    lv_draw_rect_dsc_init(&draw_dsc);
-    draw_dsc.bg_color = lv_palette_main(LV_PALETTE_LIGHT_GREEN);
-    draw_dsc.bg_opa = LV_OPA_COVER;
-    lv_point_t points[32];
-    int i, r = 150;
-    uint32_t tick = lv_tick_get();
-    for(i = 0; i < n; i++) {
-        int angle = i * 360 / n + ((tick % 36000) / 100);
-        lv_coord_t x = 150 + (r * lv_trigo_cos(angle) >> LV_TRIGO_SHIFT), y =
-                           150 + (r * lv_trigo_sin(angle) >> LV_TRIGO_SHIFT);
-        points[i].x = x;
-        points[i].y = y;
+    lv_obj_t * obj = lv_event_get_target(e);
+    lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
+    if(dsc->class_p == &lv_obj_class && dsc->part == LV_PART_MAIN) {
+        lv_draw_rect_dsc_t draw_dsc;
+        lv_draw_rect_dsc_init(&draw_dsc);
+        draw_dsc.bg_color = lv_color_hex(0xffaaaa);
+        draw_dsc.radius = LV_RADIUS_CIRCLE;
+        draw_dsc.border_color = lv_color_hex(0xff5555);
+        draw_dsc.border_width = 2;
+        draw_dsc.outline_color = lv_color_hex(0xff0000);
+        draw_dsc.outline_pad = 3;
+        draw_dsc.outline_width = 2;
+
+        lv_area_t a;
+        a.x1 = 0;
+        a.y1 = 0;
+        a.x2 = size;
+        a.y2 = size;
+        lv_area_align(&obj->coords, &a, LV_ALIGN_CENTER, 0, 0);
+
+        lv_draw_rect(dsc->draw_ctx, &draw_dsc, &a);
     }
-    lv_draw_polygon(draw_ctx, &draw_dsc, points, n);
 }
 
 /**
- * Demonstrate event bubbling
+ * Demonstrate the usage of draw event
  */
 void lv_example_event_4(void)
 {
-
     lv_obj_t * cont = lv_obj_create(lv_scr_act());
-    lv_obj_remove_style_all(cont);
-    lv_obj_set_size(cont, 300, 300);
-    label = lv_label_create(cont);
-    lv_label_set_text_fmt(label, "%d sides", n);
-    lv_obj_center(label);
-
-    lv_obj_add_event_cb(cont, event_cb, LV_EVENT_DRAW_MAIN, NULL);
-    lv_timer_create(timer_cb, 17, cont);
+    lv_obj_set_size(cont, 200, 200);
+    lv_obj_center(cont);
+    lv_obj_add_event_cb(cont, event_cb, LV_EVENT_DRAW_PART_END, NULL);
+    lv_timer_create(timer_cb, 30, cont);
 }
 
 #endif