fix(flex): don't count item gap for leading hidden items (#7720)

src/layouts/flex/lv_flex.c

@@ -254,6 +254,7 @@ static int32_t find_track_end(lv_obj_t * cont, flex_t * f, int32_t item_start_id
     int32_t item_id = item_start_id;
     int32_t grow_min_size_sum = 0;
     lv_obj_t * item = lv_obj_get_child(cont, item_id);
+    bool first_item = true;
     while(item) {
         if(item_id != item_start_id && lv_obj_has_flag(item, LV_OBJ_FLAG_FLEX_IN_NEW_TRACK)) break;
 
@@ -296,11 +297,12 @@ static int32_t find_track_end(lv_obj_t * cont, flex_t * f, int32_t item_start_id
             else {
                 int32_t item_size = get_main_size(item);
                 int32_t req_size = item_size;
-                if(item_id != item_start_id) req_size += item_gap; /*No gap before the first item*/
+                if(!first_item) req_size += item_gap; /*No gap before the first item*/
                 if(f->wrap && t->track_fix_main_size + grow_min_size_sum + req_size > max_main_size) break;
                 t->track_fix_main_size += req_size;
             }
 
+            first_item = false;
             t->track_cross_size = LV_MAX(get_cross_size(item), t->track_cross_size);
             t->item_cnt++;
         }

tests/src/test_cases/test_align_flex.c

@@ -81,7 +81,6 @@ void test_align(void)
 /*See https://github.com/lvgl/lvgl/issues/7035*/
 void test_wrap_grow_min_width(void)
 {
-
     lv_obj_set_flex_flow(lv_screen_active(), LV_FLEX_FLOW_ROW_WRAP);
     lv_obj_set_flex_align(lv_screen_active(), LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_SPACE_EVENLY);
 
@@ -106,4 +105,70 @@ void test_wrap_grow_min_width(void)
     TEST_ASSERT_EQUAL_SCREENSHOT("flex_wrap_grow_min_width.png");
 }
 
+
+static lv_obj_t  * cont_row_5_create(void)
+{
+    lv_obj_t * cont = lv_obj_create(lv_screen_active());
+    lv_obj_set_size(cont, LV_SIZE_CONTENT, LV_SIZE_CONTENT);
+    lv_obj_center(cont);
+
+    lv_obj_set_flex_flow(cont, LV_FLEX_FLOW_ROW);
+
+    for(int i = 0; i < 5; i++) {
+        lv_obj_t * btn = lv_button_create(cont);
+        lv_obj_set_size(btn, 40, 60);
+
+        lv_obj_t * label = lv_label_create(btn);
+        lv_label_set_text_fmt(label, "%d", i);
+        lv_obj_center(label);
+    }
+
+    return cont;
+}
+
+static void hide(lv_obj_t * cont, uint32_t idx)
+{
+    lv_obj_add_flag(lv_obj_get_child(cont, idx), LV_OBJ_FLAG_HIDDEN);
+}
+
+void test_flex_hide_items(void)
+{
+    lv_obj_set_flex_flow(lv_screen_active(), LV_FLEX_FLOW_COLUMN_WRAP);
+    lv_obj_set_flex_align(lv_screen_active(), LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_START, LV_FLEX_ALIGN_SPACE_EVENLY);
+
+    lv_obj_t * cont;
+    cont = cont_row_5_create();
+
+    cont = cont_row_5_create();
+    hide(cont, 0);
+
+    cont = cont_row_5_create();
+    hide(cont, 0);
+    hide(cont, 1);
+
+    cont = cont_row_5_create();
+    hide(cont, 4);
+
+    cont = cont_row_5_create();
+    hide(cont, 3);
+    hide(cont, 4);
+
+    cont = cont_row_5_create();
+    hide(cont, 0);
+    hide(cont, 1);
+    hide(cont, 3);
+    hide(cont, 4);
+
+    cont = cont_row_5_create();
+    hide(cont, 1);
+    hide(cont, 3);
+
+    cont = cont_row_5_create();
+    hide(cont, 0);
+    hide(cont, 4);
+
+    TEST_ASSERT_EQUAL_SCREENSHOT("flex_hide_items.png");
+}
+
+
 #endif