add some code

managed_components/lvgl__lvgl/examples/scroll/index.rst

@@ -0,0 +1,43 @@
+
+Nested scrolling
+----------------
+
+.. lv_example:: scroll/lv_example_scroll_1
+  :language: c
+
+Snapping
+--------
+.. lv_example:: scroll/lv_example_scroll_2
+  :language: c
+
+Floating button
+----------------
+.. lv_example:: scroll/lv_example_scroll_3
+  :language: c
+
+Styling the scrollbars
+----------------------
+.. lv_example:: scroll/lv_example_scroll_4
+  :language: c
+
+Right to left scrolling
+-----------------------
+.. lv_example:: scroll/lv_example_scroll_5
+  :language: c
+
+Translate on scroll
+-------------------
+.. lv_example:: scroll/lv_example_scroll_6
+  :language: c
+
+Infinite scrolling
+------------------
+.. lv_example:: scroll/lv_example_scroll_7
+  :language: c
+  
+circular scrolling
+------------------
+.. lv_example:: scroll/lv_example_scroll_8
+  :language: c
+
+

managed_components/lvgl__lvgl/examples/scroll/lv_example_scroll.h

@@ -0,0 +1,45 @@
+/**
+ * @file lv_example_scroll.h
+ *
+ */
+
+#ifndef LV_EXAMPLE_SCROLL_H
+#define LV_EXAMPLE_SCROLL_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*********************
+ *      INCLUDES
+ *********************/
+
+/*********************
+ *      DEFINES
+ *********************/
+
+/**********************
+ *      TYPEDEFS
+ **********************/
+
+/**********************
+ * GLOBAL PROTOTYPES
+ **********************/
+void lv_example_scroll_1(void);
+void lv_example_scroll_2(void);
+void lv_example_scroll_3(void);
+void lv_example_scroll_4(void);
+void lv_example_scroll_5(void);
+void lv_example_scroll_6(void);
+void lv_example_scroll_7(void);
+void lv_example_scroll_8(void);
+
+/**********************
+ *      MACROS
+ **********************/
+
+#ifdef __cplusplus
+} /*extern "C"*/
+#endif
+
+#endif /*LV_EXAMPLE_SCROLL_H*/

managed_components/lvgl__lvgl/examples/scroll/lv_example_scroll_1.c

@@ -0,0 +1,101 @@
+#include "../lv_examples.h"
+#if LV_BUILD_EXAMPLES
+
+static lv_obj_t  * panel;
+static lv_obj_t  * save_button;
+static lv_obj_t  * restore_button;
+static int         saved_scroll_x;
+static int         saved_scroll_y;
+
+static void scroll_update_cb(lv_event_t * e);
+static void button_event_cb(lv_event_t * e);
+
+static void scroll_update_cb(lv_event_t * e)
+{
+    LV_UNUSED(e);
+
+    LV_LOG("scroll info: x:%3" LV_PRId32", y:%3" LV_PRId32", top:%3" LV_PRId32", "
+           "bottom:%3" LV_PRId32", left:%3" LV_PRId32", right:%3" LV_PRId32"\n",
+           lv_obj_get_scroll_x(panel),
+           lv_obj_get_scroll_y(panel),
+           lv_obj_get_scroll_top(panel),
+           lv_obj_get_scroll_bottom(panel),
+           lv_obj_get_scroll_left(panel),
+           lv_obj_get_scroll_right(panel)
+          );
+}
+
+static void button_event_cb(lv_event_t * e)
+{
+    lv_obj_t * obj = lv_event_get_target_obj(e);
+
+    if(obj == save_button) {
+        saved_scroll_x = lv_obj_get_scroll_x(panel);
+        saved_scroll_y = lv_obj_get_scroll_y(panel);
+    }
+    else {
+        lv_obj_scroll_to(panel, saved_scroll_x, saved_scroll_y, LV_ANIM_ON);
+    }
+}
+
+/**
+ * Demonstrate how scrolling appears automatically
+ */
+void lv_example_scroll_1(void)
+{
+    /*Create an object with the new style*/
+    lv_obj_t * scr;
+    scr = lv_screen_active();
+    panel = lv_obj_create(scr);
+    lv_obj_set_size(panel, 200, 200);
+    lv_obj_align(panel, LV_ALIGN_CENTER, 44, 0);
+
+    lv_obj_t * child;
+    lv_obj_t * label;
+
+    child = lv_obj_create(panel);
+    lv_obj_set_pos(child, 0, 0);
+    lv_obj_set_size(child, 70, 70);
+    label = lv_label_create(child);
+    lv_label_set_text(label, "Zero");
+    lv_obj_center(label);
+
+    child = lv_obj_create(panel);
+    lv_obj_set_pos(child, 160, 80);
+    lv_obj_set_size(child, 80, 80);
+
+    lv_obj_t * child2 = lv_button_create(child);
+    lv_obj_set_size(child2, 100, 50);
+
+    label = lv_label_create(child2);
+    lv_label_set_text(label, "Right");
+    lv_obj_center(label);
+
+    child = lv_obj_create(panel);
+    lv_obj_set_pos(child, 40, 160);
+    lv_obj_set_size(child, 100, 70);
+    label = lv_label_create(child);
+    lv_label_set_text(label, "Bottom");
+    lv_obj_center(label);
+
+    /* When LV_OBJ_FLAG_SCROLL_ELASTIC is cleared, scrolling does not go past edge bounaries. */
+    /* lv_obj_clear_flag(panel, LV_OBJ_FLAG_SCROLL_ELASTIC); */
+
+    /* Call `scroll_update_cb` while panel is being scrolled. */
+    lv_obj_add_event_cb(panel, scroll_update_cb, LV_EVENT_SCROLL, NULL);
+
+    /* Set up buttons that save and restore scroll position. */
+    save_button = lv_button_create(scr);
+    restore_button = lv_button_create(scr);
+    lv_obj_t * lbl;
+    lbl = lv_label_create(save_button);
+    lv_label_set_text_static(lbl, "Save");
+    lbl = lv_label_create(restore_button);
+    lv_label_set_text_static(lbl, "Restore");
+    lv_obj_align_to(save_button, panel, LV_ALIGN_OUT_LEFT_MID, -10, -20);
+    lv_obj_align_to(restore_button, panel, LV_ALIGN_OUT_LEFT_MID, -10, 20);
+    lv_obj_add_event_cb(save_button, button_event_cb, LV_EVENT_CLICKED, NULL);
+    lv_obj_add_event_cb(restore_button, button_event_cb, LV_EVENT_CLICKED, NULL);
+}
+
+#endif

managed_components/lvgl__lvgl/examples/scroll/lv_example_scroll_2.c

@@ -0,0 +1,57 @@
+#include "../lv_examples.h"
+#if LV_BUILD_EXAMPLES && LV_USE_FLEX
+
+static void sw_event_cb(lv_event_t * e)
+{
+    lv_event_code_t code = lv_event_get_code(e);
+    lv_obj_t * sw = lv_event_get_target_obj(e);
+
+    if(code == LV_EVENT_VALUE_CHANGED) {
+        lv_obj_t * list = (lv_obj_t *) lv_event_get_user_data(e);
+
+        if(lv_obj_has_state(sw, LV_STATE_CHECKED)) lv_obj_add_flag(list, LV_OBJ_FLAG_SCROLL_ONE);
+        else lv_obj_remove_flag(list, LV_OBJ_FLAG_SCROLL_ONE);
+    }
+}
+
+/**
+ * Show an example to scroll snap
+ */
+void lv_example_scroll_2(void)
+{
+    lv_obj_t * panel = lv_obj_create(lv_screen_active());
+    lv_obj_set_size(panel, 280, 120);
+    lv_obj_set_scroll_snap_x(panel, LV_SCROLL_SNAP_CENTER);
+    lv_obj_set_flex_flow(panel, LV_FLEX_FLOW_ROW);
+    lv_obj_align(panel, LV_ALIGN_CENTER, 0, 20);
+
+    uint32_t i;
+    for(i = 0; i < 10; i++) {
+        lv_obj_t * btn = lv_button_create(panel);
+        lv_obj_set_size(btn, 150, lv_pct(100));
+
+        lv_obj_t * label = lv_label_create(btn);
+        if(i == 3) {
+            lv_label_set_text_fmt(label, "Panel %" LV_PRIu32"\nno snap", i);
+            lv_obj_remove_flag(btn, LV_OBJ_FLAG_SNAPPABLE);
+        }
+        else {
+            lv_label_set_text_fmt(label, "Panel %" LV_PRIu32, i);
+        }
+
+        lv_obj_center(label);
+    }
+    lv_obj_update_snap(panel, LV_ANIM_ON);
+
+#if LV_USE_SWITCH
+    /*Switch between "One scroll" and "Normal scroll" mode*/
+    lv_obj_t * sw = lv_switch_create(lv_screen_active());
+    lv_obj_align(sw, LV_ALIGN_TOP_RIGHT, -20, 10);
+    lv_obj_add_event_cb(sw, sw_event_cb, LV_EVENT_ALL, panel);
+    lv_obj_t * label = lv_label_create(lv_screen_active());
+    lv_label_set_text(label, "One scroll");
+    lv_obj_align_to(label, sw, LV_ALIGN_OUT_BOTTOM_MID, 0, 5);
+#endif
+}
+
+#endif

managed_components/lvgl__lvgl/examples/scroll/lv_example_scroll_3.c

@@ -0,0 +1,49 @@
+#include "../lv_examples.h"
+#if LV_BUILD_EXAMPLES && LV_USE_LIST
+
+static uint32_t btn_cnt = 1;
+
+static void float_button_event_cb(lv_event_t * e)
+{
+    lv_event_code_t code = lv_event_get_code(e);
+    lv_obj_t * float_btn = lv_event_get_target_obj(e);
+
+    if(code == LV_EVENT_CLICKED) {
+        lv_obj_t * list = (lv_obj_t *) lv_event_get_user_data(e);
+        char buf[32];
+        lv_snprintf(buf, sizeof(buf), "Track %d", (int)btn_cnt);
+        lv_obj_t * list_btn = lv_list_add_button(list, LV_SYMBOL_AUDIO, buf);
+        btn_cnt++;
+
+        lv_obj_move_foreground(float_btn);
+
+        lv_obj_scroll_to_view(list_btn, LV_ANIM_ON);
+    }
+}
+
+/**
+ * Create a list with a floating button
+ */
+void lv_example_scroll_3(void)
+{
+    lv_obj_t * list = lv_list_create(lv_screen_active());
+    lv_obj_set_size(list, 280, 220);
+    lv_obj_center(list);
+
+    for(btn_cnt = 1; btn_cnt <= 2; btn_cnt++) {
+        char buf[32];
+        lv_snprintf(buf, sizeof(buf), "Track %d", (int)btn_cnt);
+        lv_list_add_button(list, LV_SYMBOL_AUDIO, buf);
+    }
+
+    lv_obj_t * float_btn = lv_button_create(list);
+    lv_obj_set_size(float_btn, 50, 50);
+    lv_obj_add_flag(float_btn, LV_OBJ_FLAG_FLOATING);
+    lv_obj_align(float_btn, LV_ALIGN_BOTTOM_RIGHT, 0, -lv_obj_get_style_pad_right(list, LV_PART_MAIN));
+    lv_obj_add_event_cb(float_btn, float_button_event_cb, LV_EVENT_ALL, list);
+    lv_obj_set_style_radius(float_btn, LV_RADIUS_CIRCLE, 0);
+    lv_obj_set_style_bg_image_src(float_btn, LV_SYMBOL_PLUS, 0);
+    lv_obj_set_style_text_font(float_btn, lv_theme_get_font_large(float_btn), 0);
+}
+
+#endif

managed_components/lvgl__lvgl/examples/scroll/lv_example_scroll_4.c

@@ -0,0 +1,67 @@
+#include "../lv_examples.h"
+#if LV_BUILD_EXAMPLES && LV_USE_LIST
+
+/**
+ * Styling the scrollbars
+ */
+void lv_example_scroll_4(void)
+{
+    lv_obj_t * obj = lv_obj_create(lv_screen_active());
+    lv_obj_set_size(obj, 200, 100);
+    lv_obj_center(obj);
+
+    lv_obj_t * label = lv_label_create(obj);
+    lv_label_set_text(label,
+                      "Lorem ipsum dolor sit amet, consectetur adipiscing elit.\n"
+                      "Etiam dictum, tortor vestibulum lacinia laoreet, mi neque consectetur neque, vel mattis odio dolor egestas ligula. \n"
+                      "Sed vestibulum sapien nulla, id convallis ex porttitor nec. \n"
+                      "Duis et massa eu libero accumsan faucibus a in arcu. \n"
+                      "Ut pulvinar odio lorem, vel tempus turpis condimentum quis. Nam consectetur condimentum sem in auctor. \n"
+                      "Sed nisl augue, venenatis in blandit et, gravida ac tortor. \n"
+                      "Etiam dapibus elementum suscipit. \n"
+                      "Proin mollis sollicitudin convallis. \n"
+                      "Integer dapibus tempus arcu nec viverra. \n"
+                      "Donec molestie nulla enim, eu interdum velit placerat quis. \n"
+                      "Donec id efficitur risus, at molestie turpis. \n"
+                      "Suspendisse vestibulum consectetur nunc ut commodo. \n"
+                      "Fusce molestie rhoncus nisi sit amet tincidunt. \n"
+                      "Suspendisse a nunc ut magna ornare volutpat.");
+
+    /*Remove the style of scrollbar to have clean start*/
+    lv_obj_remove_style(obj, NULL, LV_PART_SCROLLBAR | LV_STATE_ANY);
+
+    /*Create a transition the animate the some properties on state change*/
+    static const lv_style_prop_t props[] = {LV_STYLE_BG_OPA, LV_STYLE_WIDTH, 0};
+    static lv_style_transition_dsc_t trans;
+    lv_style_transition_dsc_init(&trans, props, lv_anim_path_linear, 200, 0, NULL);
+
+    /*Create a style for the scrollbars*/
+    static lv_style_t style;
+    lv_style_init(&style);
+    lv_style_set_width(&style, 4);      /*Width of the scrollbar*/
+    lv_style_set_length(&style, 20);    /*Length of the scrollbar*/
+    lv_style_set_pad_right(&style, 5);  /*Space from the parallel side*/
+    lv_style_set_pad_top(&style, 5);    /*Space from the perpendicular side*/
+
+    lv_style_set_radius(&style, 2);
+    lv_style_set_bg_opa(&style, LV_OPA_70);
+    lv_style_set_bg_color(&style, lv_palette_main(LV_PALETTE_BLUE));
+    lv_style_set_border_color(&style, lv_palette_darken(LV_PALETTE_BLUE, 3));
+    lv_style_set_border_width(&style, 2);
+    lv_style_set_shadow_width(&style, 8);
+    lv_style_set_shadow_spread(&style, 2);
+    lv_style_set_shadow_color(&style, lv_palette_darken(LV_PALETTE_BLUE, 1));
+
+    lv_style_set_transition(&style, &trans);
+
+    /*Make the scrollbars wider and use 100% opacity when scrolled*/
+    static lv_style_t style_scrolled;
+    lv_style_init(&style_scrolled);
+    lv_style_set_width(&style_scrolled, 8);
+    lv_style_set_bg_opa(&style_scrolled, LV_OPA_COVER);
+
+    lv_obj_add_style(obj, &style, LV_PART_SCROLLBAR);
+    lv_obj_add_style(obj, &style_scrolled, LV_PART_SCROLLBAR | LV_STATE_SCROLLED);
+}
+
+#endif

managed_components/lvgl__lvgl/examples/scroll/lv_example_scroll_5.c

@@ -0,0 +1,22 @@
+#include "../lv_examples.h"
+#if LV_BUILD_EXAMPLES && LV_FONT_DEJAVU_16_PERSIAN_HEBREW
+
+/**
+ * Scrolling with Right To Left base direction
+ */
+void lv_example_scroll_5(void)
+{
+    lv_obj_t * obj = lv_obj_create(lv_screen_active());
+    lv_obj_set_style_base_dir(obj, LV_BASE_DIR_RTL, 0);
+    lv_obj_set_size(obj, 200, 100);
+    lv_obj_center(obj);
+
+    lv_obj_t * label = lv_label_create(obj);
+    lv_label_set_text(label,
+                      "میکروکُنترولر (به انگلیسی: Microcontroller) گونه‌ای ریزپردازنده است که دارای حافظهٔ دسترسی تصادفی (RAM) و حافظهٔ فقط‌خواندنی (ROM)، تایمر، پورت‌های ورودی و خروجی (I/O) و درگاه ترتیبی (Serial Port پورت سریال)، درون خود تراشه است، و می‌تواند به تنهایی ابزارهای دیگر را کنترل کند. به عبارت دیگر یک میکروکنترلر، مدار مجتمع کوچکی است که از یک CPU کوچک و اجزای دیگری مانند تایمر، درگاه‌های ورودی و خروجی آنالوگ و دیجیتال و حافظه تشکیل شده‌است.");
+    lv_obj_set_width(label, 400);
+    lv_obj_set_style_text_font(label, &lv_font_dejavu_16_persian_hebrew, 0);
+
+}
+
+#endif

managed_components/lvgl__lvgl/examples/scroll/lv_example_scroll_6.c

@@ -0,0 +1,80 @@
+#include "../lv_examples.h"
+#if LV_BUILD_EXAMPLES && LV_USE_FLEX
+
+static void scroll_event_cb(lv_event_t * e)
+{
+    lv_obj_t * cont = lv_event_get_target_obj(e);
+
+    lv_area_t cont_a;
+    lv_obj_get_coords(cont, &cont_a);
+    int32_t cont_y_center = cont_a.y1 + lv_area_get_height(&cont_a) / 2;
+
+    int32_t r = lv_obj_get_height(cont) * 7 / 10;
+    int32_t i;
+    int32_t child_cnt = (int32_t)lv_obj_get_child_count(cont);
+    for(i = 0; i < child_cnt; i++) {
+        lv_obj_t * child = lv_obj_get_child(cont, i);
+        lv_area_t child_a;
+        lv_obj_get_coords(child, &child_a);
+
+        int32_t child_y_center = child_a.y1 + lv_area_get_height(&child_a) / 2;
+
+        int32_t diff_y = child_y_center - cont_y_center;
+        diff_y = LV_ABS(diff_y);
+
+        /*Get the x of diff_y on a circle.*/
+        int32_t x;
+        /*If diff_y is out of the circle use the last point of the circle (the radius)*/
+        if(diff_y >= r) {
+            x = r;
+        }
+        else {
+            /*Use Pythagoras theorem to get x from radius and y*/
+            uint32_t x_sqr = r * r - diff_y * diff_y;
+            lv_sqrt_res_t res;
+            lv_sqrt(x_sqr, &res, 0x8000);   /*Use lvgl's built in sqrt root function*/
+            x = r - res.i;
+        }
+
+        /*Translate the item by the calculated X coordinate*/
+        lv_obj_set_style_translate_x(child, x, 0);
+
+        /*Use some opacity with larger translations*/
+        lv_opa_t opa = (lv_opa_t)lv_map(x, 0, r, LV_OPA_TRANSP, LV_OPA_COVER);
+        lv_obj_set_style_opa(child, LV_OPA_COVER - opa, 0);
+    }
+}
+
+/**
+ * Translate the object as they scroll
+ */
+void lv_example_scroll_6(void)
+{
+    lv_obj_t * cont = lv_obj_create(lv_screen_active());
+    lv_obj_set_size(cont, 200, 200);
+    lv_obj_center(cont);
+    lv_obj_set_flex_flow(cont, LV_FLEX_FLOW_COLUMN);
+    lv_obj_add_event_cb(cont, scroll_event_cb, LV_EVENT_SCROLL, NULL);
+    lv_obj_set_style_radius(cont, LV_RADIUS_CIRCLE, 0);
+    lv_obj_set_style_clip_corner(cont, true, 0);
+    lv_obj_set_scroll_dir(cont, LV_DIR_VER);
+    lv_obj_set_scroll_snap_y(cont, LV_SCROLL_SNAP_CENTER);
+    lv_obj_set_scrollbar_mode(cont, LV_SCROLLBAR_MODE_OFF);
+
+    uint32_t i;
+    for(i = 0; i < 20; i++) {
+        lv_obj_t * btn = lv_button_create(cont);
+        lv_obj_set_width(btn, lv_pct(100));
+
+        lv_obj_t * label = lv_label_create(btn);
+        lv_label_set_text_fmt(label, "Button %" LV_PRIu32, i);
+    }
+
+    /*Update the buttons position manually for first*/
+    lv_obj_send_event(cont, LV_EVENT_SCROLL, NULL);
+
+    /*Be sure the fist button is in the middle*/
+    lv_obj_scroll_to_view(lv_obj_get_child(cont, 0), LV_ANIM_OFF);
+}
+
+#endif

managed_components/lvgl__lvgl/examples/scroll/lv_example_scroll_7.c

@@ -0,0 +1,126 @@
+#include "../lv_examples.h"
+#if LV_BUILD_EXAMPLES && LV_USE_FLEX
+
+static lv_obj_t * high_label;
+static lv_obj_t * low_label;
+static int32_t top_num;
+static int32_t bottom_num;
+static bool update_scroll_running = false;
+
+static lv_obj_t * load_item(lv_obj_t * parent, int32_t num)
+{
+    lv_obj_t * obj = (lv_obj_t *) lv_obj_create(parent);
+    lv_obj_set_size(obj, LV_PCT(100), LV_SIZE_CONTENT);
+    lv_obj_t * label = lv_label_create(obj);
+    lv_label_set_text_fmt(label, "%" PRId32, num);
+    return obj;
+}
+
+static void update_scroll(lv_obj_t * obj)
+{
+    /* do not re-enter this function when `lv_obj_scroll_by`
+     * triggers this callback again.
+     */
+    if(update_scroll_running) return;
+    update_scroll_running = true;
+
+    int32_t top_num_original = top_num;
+    int32_t bottom_num_original = bottom_num;
+
+    /* load items we're getting close to */
+    while(bottom_num > -30 && lv_obj_get_scroll_bottom(obj) < 200) {
+        bottom_num -= 1;
+        load_item(obj, bottom_num);
+        lv_obj_update_layout(obj);
+        LV_LOG_USER("loaded bottom num: %" PRId32, bottom_num);
+    }
+    while(top_num < 30 && lv_obj_get_scroll_top(obj) < 200) {
+        top_num += 1;
+        int32_t bottom_before = lv_obj_get_scroll_bottom(obj);
+        lv_obj_t * new_item = load_item(obj, top_num);
+        lv_obj_move_to_index(new_item, 0);
+        lv_obj_update_layout(obj);
+        int32_t bottom_after = lv_obj_get_scroll_bottom(obj);
+        lv_obj_scroll_by(obj, 0, bottom_before - bottom_after, LV_ANIM_OFF);
+        LV_LOG_USER("loaded top num: %" PRId32, top_num);
+    }
+
+    /* delete far-away items */
+    while(lv_obj_get_scroll_bottom(obj) > 600) {
+        bottom_num += 1;
+        lv_obj_t * child = lv_obj_get_child(obj, -1);
+        lv_obj_delete(child);
+        lv_obj_update_layout(obj);
+        LV_LOG_USER("deleted bottom num: %" PRId32, bottom_num);
+    }
+    while(lv_obj_get_scroll_top(obj) > 600) {
+        top_num -= 1;
+        int32_t bottom_before = lv_obj_get_scroll_bottom(obj);
+        lv_obj_t * child = lv_obj_get_child(obj, 0);
+        lv_obj_delete(child);
+        lv_obj_update_layout(obj);
+        int32_t bottom_after = lv_obj_get_scroll_bottom(obj);
+        lv_obj_scroll_by(obj, 0, bottom_before - bottom_after, LV_ANIM_OFF);
+        LV_LOG_USER("deleted top num: %" PRId32, top_num);
+    }
+
+    if(top_num != top_num_original) {
+        lv_label_set_text_fmt(high_label, "current largest\nloaded value:\n%" PRId32, top_num);
+    }
+    if(bottom_num != bottom_num_original) {
+        lv_label_set_text_fmt(low_label, "current smallest\nloaded value:\n%" PRId32, bottom_num);
+    }
+
+    update_scroll_running = false;
+}
+
+static void scroll_cb(lv_event_t * e)
+{
+    lv_obj_t * obj = lv_event_get_target_obj(e);
+    update_scroll(obj);
+}
+
+static void checkbox_cb(lv_event_t * e)
+{
+    lv_obj_t * checkbox = lv_event_get_target_obj(e);
+    lv_obj_t * obj = (lv_obj_t *) lv_event_get_user_data(e);
+    bool checked = lv_obj_has_state(checkbox, LV_STATE_CHECKED);
+    lv_obj_set_style_opa(obj, checked ? LV_OPA_COVER : LV_OPA_TRANSP, LV_PART_SCROLLBAR);
+}
+
+/**
+ * Dynamically load widgets while scrolling
+ */
+void lv_example_scroll_7(void)
+{
+    lv_obj_t * scr = lv_screen_active();
+    lv_obj_t * obj = lv_obj_create(scr);
+    lv_obj_set_size(obj, 160, 220);
+    lv_obj_align(obj, LV_ALIGN_RIGHT_MID, -10, 0);
+    lv_obj_set_flex_flow(obj, LV_FLEX_FLOW_COLUMN);
+    lv_obj_set_style_opa(obj, LV_OPA_TRANSP, LV_PART_SCROLLBAR);
+
+    high_label = lv_label_create(scr);
+    lv_label_set_text_static(high_label, "current largest\nloaded value:");
+    lv_obj_align(high_label, LV_ALIGN_TOP_LEFT, 10, 10);
+
+    lv_obj_t * checkbox = lv_checkbox_create(scr);
+    lv_checkbox_set_text_static(checkbox, "show\nscrollbar");
+    lv_obj_align(checkbox, LV_ALIGN_LEFT_MID, 10, 0);
+    lv_obj_add_event_cb(checkbox, checkbox_cb, LV_EVENT_VALUE_CHANGED, obj);
+
+    low_label = lv_label_create(scr);
+    lv_label_set_text_static(low_label, "current smallest\nloaded value:");
+    lv_obj_align(low_label, LV_ALIGN_BOTTOM_LEFT, 10, -10);
+
+    load_item(obj, 3);
+    /* These counters hold the the highest/lowest number currently loaded. */
+    top_num = 3;
+    bottom_num = 3;
+
+    lv_obj_update_layout(obj);
+    update_scroll(obj);
+    lv_obj_add_event_cb(obj, scroll_cb, LV_EVENT_SCROLL, NULL);
+}
+
+#endif

managed_components/lvgl__lvgl/examples/scroll/lv_example_scroll_8.c

@@ -0,0 +1,146 @@
+#include "../lv_examples.h"
+#if LV_BUILD_EXAMPLES && LV_USE_FLEX
+
+
+/*
+ * Circular list implementation based on:
+ * Reference: https://blog.csdn.net/TQW4321/article/details/145434819
+ */
+
+/* Applies to both width (for row items) and height (for column items) */
+#define ITEM_SIZE     80
+
+/* Function to calculate the total content width of the container */
+static int32_t get_content_width(lv_obj_t * cont)
+{
+    int32_t w = 0;
+    int32_t pad_column = lv_obj_get_style_pad_column(cont, LV_PART_MAIN); // 列间距
+    int32_t total = (int32_t)lv_obj_get_child_count(cont);
+
+    for(int32_t i = 0; i < total; i++) {
+        w += lv_obj_get_width(lv_obj_get_child(cont, i));
+        if(i < total - 1) w += pad_column;
+    }
+    return w + lv_obj_get_style_pad_left(cont, LV_PART_MAIN)
+           + lv_obj_get_style_pad_right(cont, LV_PART_MAIN);
+}
+
+/* Scroll event callback for row layout */
+static void cont_row_scroll_event_cb(lv_event_t * e)
+{
+    static bool is_adjusting = false;
+    lv_obj_t * cont = lv_event_get_current_target_obj(e);
+
+    if(!is_adjusting) {
+        is_adjusting = true;
+        int32_t scroll_x = lv_obj_get_scroll_x(cont);
+        int32_t cont_w = lv_obj_get_width(cont);
+        int32_t content_w = get_content_width(cont);
+
+        /* Use ITEM_SIZE as horizontal item width */
+        const int32_t item_width = ITEM_SIZE;
+
+        if(scroll_x <= 0) {
+            lv_obj_t * last_child = lv_obj_get_child(cont, (int32_t)(lv_obj_get_child_count(cont) - 1));
+            lv_obj_move_to_index(last_child, 0);
+            lv_obj_scroll_to_x(cont, scroll_x + item_width, LV_ANIM_OFF);
+        }
+        else if(scroll_x > content_w - cont_w) {
+            lv_obj_t * first_child = lv_obj_get_child(cont, 0);
+            lv_obj_move_to_index(first_child, (int32_t)(lv_obj_get_child_count(cont) - 1));
+            lv_obj_scroll_to_x(cont, scroll_x - item_width, LV_ANIM_OFF);
+        }
+        is_adjusting = false;
+    }
+}
+
+/* Function to calculate the total content height of the container */
+static int32_t get_content_height(lv_obj_t * cont)
+{
+    int32_t h = 0;
+    int32_t pad_row = lv_obj_get_style_pad_row(cont, LV_PART_MAIN);
+    int32_t total = (int32_t)lv_obj_get_child_count(cont);
+
+    for(int i = 0; i < total; i++) {
+        h += lv_obj_get_height(lv_obj_get_child(cont, i));
+        if(i < total - 1) h += pad_row;
+    }
+    return h + lv_obj_get_style_pad_top(cont, LV_PART_MAIN)
+           + lv_obj_get_style_pad_bottom(cont, LV_PART_MAIN);
+}
+
+/* Scroll event callback for column layout */
+static void cont_col_scroll_event_cb(lv_event_t * e)
+{
+    static bool is_adjusting = false;
+    lv_obj_t * cont = lv_event_get_current_target_obj(e);
+
+    if(!is_adjusting) {
+        is_adjusting = true;
+        int32_t scroll_y = lv_obj_get_scroll_y(cont);
+        int32_t cont_h = lv_obj_get_height(cont);
+        int32_t content_h = get_content_height(cont);
+
+        /* Use ITEM_SIZE as vertical item height */
+        const int32_t item_height = ITEM_SIZE;
+
+        if(scroll_y <= 0) {
+            lv_obj_t * last_child = lv_obj_get_child(cont, (int32_t)(lv_obj_get_child_count(cont) - 1));
+            lv_obj_move_to_index(last_child, 0);
+            lv_obj_scroll_to_y(cont, scroll_y + item_height, LV_ANIM_OFF);
+        }
+        else if(scroll_y > content_h - cont_h) {
+            lv_obj_t * first_child = lv_obj_get_child(cont, 0);
+            lv_obj_move_to_index(first_child, (int32_t)(lv_obj_get_child_count(cont) - 1));
+            lv_obj_scroll_to_y(cont, scroll_y - item_height, LV_ANIM_OFF);
+        }
+        is_adjusting = false;
+    }
+}
+
+void lv_example_scroll_8(void)
+{
+    /* Create a scroll container with ROW flex direction */
+    lv_obj_t * cont_row = lv_obj_create(lv_screen_active());
+    lv_obj_set_size(cont_row, 300, 75);
+    lv_obj_align(cont_row, LV_ALIGN_TOP_MID, 0, 5);
+    lv_obj_set_flex_flow(cont_row, LV_FLEX_FLOW_ROW);
+    lv_obj_add_event_cb(cont_row, cont_row_scroll_event_cb, LV_EVENT_SCROLL, NULL);
+    /* Hide scrollbar visuals */
+    lv_obj_set_scrollbar_mode(cont_row, LV_SCROLLBAR_MODE_OFF);
+
+    /* Create a scroll container with COLUMN flex direction */
+    lv_obj_t * cont_col = lv_obj_create(lv_screen_active());
+    lv_obj_set_size(cont_col, 200, 150);
+    lv_obj_align_to(cont_col, cont_row, LV_ALIGN_OUT_BOTTOM_MID, 0, 5);
+    lv_obj_set_flex_flow(cont_col, LV_FLEX_FLOW_COLUMN);
+    lv_obj_add_event_cb(cont_col, cont_col_scroll_event_cb, LV_EVENT_SCROLL, NULL);
+    /* Hide scrollbar visuals */
+    lv_obj_set_scrollbar_mode(cont_col, LV_SCROLLBAR_MODE_OFF);
+
+    /* If the number of items is less than 3, scrolling may not be needed or may cause unexpected behavior. */
+    uint32_t i;
+    for(i = 0; i < 10; i++) {
+        lv_obj_t * obj;
+        lv_obj_t * label;
+
+        /*Add items to the row*/
+        obj = lv_button_create(cont_row);
+        lv_obj_set_size(obj, ITEM_SIZE, LV_PCT(100));
+
+        label = lv_label_create(obj);
+        lv_label_set_text_fmt(label, "Item %" LV_PRIu32, i + 1);
+        lv_obj_center(label);
+
+        /*Add items to the column*/
+        obj = lv_button_create(cont_col);
+        lv_obj_set_size(obj, LV_PCT(100), ITEM_SIZE);
+
+        label = lv_label_create(obj);
+        lv_label_set_text_fmt(label, "Item %" LV_PRIu32, i + 1);
+        lv_obj_center(label);
+    }
+}
+
+
+#endif