feat(core): add external data and destructor feature (#9112)

Signed-off-by: chenwen@espressif.com <chenwen@espressif.com>

Kconfig

@@ -832,6 +832,23 @@ menu "LVGL configuration"
 				bool "Enable the multi-touch gesture recognition feature"
 				depends on LV_USE_FLOAT
 				default n
+
+			config LV_USE_EXT_DATA
+				bool "External data and destructor"
+				default n
+				help
+					Enable this option to activate external data and destructor functionality,
+					which assists in resource cleanup when objects are freed by either LVGL core
+					or applications. Currently supported features include:
+						- event
+						- object
+						- observer
+						- anim
+						- timer
+						- group
+						- display
+						- indev (input device)
+						- theme
 		endmenu
 	endmenu
 

lv_conf_template.h

@@ -1400,6 +1400,9 @@
     #define LV_QNX_BUF_COUNT        1    /**< 1 or 2 */
 #endif
 
+/** Enable or disable for external data and destructor function */
+#define LV_USE_EXT_DATA   0
+
 /*=====================
 * BUILD OPTIONS
 *======================*/

src/core/lv_group.c

@@ -67,6 +67,10 @@ lv_group_t * lv_group_create(void)
     group->refocus_policy = LV_GROUP_REFOCUS_POLICY_PREV;
     group->wrap           = 1;
     group->user_data      = NULL;
+#if LV_USE_EXT_DATA
+    group->ext_data.free_cb = NULL;
+    group->ext_data.data = NULL;
+#endif
 
     return group;
 }
@@ -100,6 +104,12 @@ void lv_group_delete(lv_group_t * group)
 
     lv_ll_clear(&(group->obj_ll));
     lv_ll_remove(group_ll_p, group);
+#if LV_USE_EXT_DATA
+    if(group->ext_data.free_cb) {
+        group->ext_data.free_cb(group->ext_data.data);
+        group->ext_data.data = NULL;
+    }
+#endif
     lv_free(group);
 }
 
@@ -410,6 +420,20 @@ lv_group_t  * lv_group_by_index(uint32_t index)
 
     return NULL;
 }
+
+#if LV_USE_EXT_DATA
+void lv_group_set_external_data(lv_group_t * group, void * data, void (* free_cb)(void * data))
+{
+    if(!group) {
+        LV_LOG_WARN("Can't attach external user data and destructor callback to a NULL group");
+        return;
+    }
+
+    group->ext_data.data = data;
+    group->ext_data.free_cb = free_cb;
+}
+#endif
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/

src/core/lv_group.h

@@ -237,6 +237,22 @@ uint32_t lv_group_get_count(void);
  */
 lv_group_t  * lv_group_by_index(uint32_t index);
 
+#if LV_USE_EXT_DATA
+/**
+ * @brief Attaches external user data and destructor callback to a group
+ *
+ * Associates custom user data with an LVGL group and specifies a destructor function
+ * that will be automatically invoked when the group is deleted to properly clean up
+ * the associated resources.
+ *
+ * @param group      Pointer to a group
+ * @param data       User-defined data pointer to associate with a group
+ * @param free_cb    Callback function for cleaning up ext_data when group is deleted.
+ *                   Receives ext_data as parameter. NULL means no cleanup required.
+ */
+void lv_group_set_external_data(lv_group_t * group, void * data, void (* free_cb)(void * data));
+#endif
+
 /**********************
  *      MACROS
  **********************/

src/core/lv_group_private.h

@@ -16,6 +16,10 @@ extern "C" {
 
 #include "lv_group.h"
 
+#if LV_USE_EXT_DATA
+#include "../lvgl_private.h"
+#endif
+
 /*********************
  *      DEFINES
  *********************/
@@ -29,6 +33,9 @@ extern "C" {
  * They are NOT for laying out objects on a screen (try layouts for that).
  */
 struct _lv_group_t {
+#if LV_USE_EXT_DATA
+    lv_ext_data_t ext_data;
+#endif
     lv_ll_t obj_ll;        /**< Linked list to store the objects in the group*/
     lv_obj_t ** obj_focus; /**< The object in focus*/
 

src/core/lv_obj_class.c

@@ -135,6 +135,13 @@ void lv_obj_class_init_obj(lv_obj_t * obj)
 
 void lv_obj_destruct(lv_obj_t * obj)
 {
+#if LV_USE_EXT_DATA
+    if(obj->ext_data.free_cb) {
+        obj->ext_data.free_cb(obj->ext_data.data);
+        obj->ext_data.data = NULL;
+    }
+#endif
+
     if(obj->class_p->destructor_cb) obj->class_p->destructor_cb(obj->class_p, obj);
 
     if(obj->class_p->base_class) {
@@ -170,6 +177,19 @@ bool lv_obj_is_group_def(lv_obj_t * obj)
     return class_p->group_def == LV_OBJ_CLASS_GROUP_DEF_TRUE;
 }
 
+#if LV_USE_EXT_DATA
+void lv_obj_set_external_data(lv_obj_t * obj, void * data, void (* free_cb)(void * data))
+{
+    if(!obj) {
+        LV_LOG_WARN("Can't attach external user data and destructor callback to a NULL object");
+        return;
+    }
+
+    obj->ext_data.data = data;
+    obj->ext_data.free_cb = free_cb;
+}
+#endif
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/
@@ -177,6 +197,12 @@ bool lv_obj_is_group_def(lv_obj_t * obj)
 static void lv_obj_construct(const lv_obj_class_t * class_p, lv_obj_t * obj)
 {
     LV_ASSERT_NULL(class_p->name);
+
+#if LV_USE_EXT_DATA
+    obj->ext_data.free_cb = NULL;
+    obj->ext_data.data = NULL;
+#endif
+
     if(obj->class_p->base_class) {
         const lv_obj_class_t * original_class_p = obj->class_p;
 

src/core/lv_obj_class.h

@@ -61,6 +61,23 @@ bool lv_obj_is_editable(lv_obj_t * obj);
 
 bool lv_obj_is_group_def(lv_obj_t * obj);
 
+#if LV_USE_EXT_DATA
+/**
+ * @brief Associates an array of external data pointers with an LVGL object
+ *
+ * Associates custom user data with an LVGL object and specifies a destructor function
+ * that will be automatically invoked when the object is deleted to properly clean up
+ * the associated resources.
+ *
+ * @param obj          Target LVGL object
+ * @param data         User-defined data pointer to associate with a object
+ * @param free_cb      Cleanup function called for each non-NULL data pointer during
+ *                     object deletion. Receives single data pointer as parameter.
+ *                     NULL means no automatic cleanup.
+ */
+void lv_obj_set_external_data(lv_obj_t * obj, void * data, void (* free_cb)(void * data));
+#endif
+
 /**********************
  *      MACROS
  **********************/

src/core/lv_obj_private.h

@@ -16,6 +16,10 @@ extern "C" {
 
 #include "lv_obj.h"
 
+#if LV_USE_EXT_DATA
+#include "../lvgl_private.h"
+#endif
+
 /*********************
  *      DEFINES
  *********************/
@@ -53,6 +57,9 @@ struct _lv_obj_spec_attr_t {
 };
 
 struct _lv_obj_t {
+#if LV_USE_EXT_DATA
+    lv_ext_data_t ext_data;
+#endif
     const lv_obj_class_t * class_p;
     lv_obj_t * parent;
     lv_obj_spec_attr_t * spec_attr;

src/core/lv_observer.c

@@ -91,6 +91,19 @@ static void subject_set_string_free_user_data_event_cb(lv_event_t * e);
  *   GLOBAL FUNCTIONS
  **********************/
 
+#if LV_USE_EXT_DATA
+void lv_subject_set_external_data(lv_subject_t * subject, void * data, void (* free_cb)(void * data))
+{
+    if(!subject) {
+        LV_LOG_WARN("Can't attach external user data and destructor callback to a NULL subject");
+        return;
+    }
+
+    subject->ext_data.data = data;
+    subject->ext_data.free_cb = free_cb;
+}
+#endif
+
 void lv_subject_init_int(lv_subject_t * subject, int32_t value)
 {
     lv_memzero(subject, sizeof(lv_subject_t));
@@ -498,6 +511,13 @@ void lv_observer_remove(lv_observer_t * observer)
 
     observer->subject->notify_restart_query = 1;
 
+#if LV_USE_EXT_DATA
+    if(observer->subject->ext_data.free_cb) {
+        observer->subject->ext_data.free_cb(observer->subject->ext_data.data);
+        observer->subject->ext_data.data = NULL;
+    }
+#endif
+
     lv_ll_remove(&(observer->subject->subs_ll), observer);
 
     if(observer->auto_free_user_data) {

src/core/lv_observer.h

@@ -16,6 +16,10 @@ extern "C" {
 
 #include "lv_obj.h"
 
+#if LV_USE_EXT_DATA
+#include "../lvgl_private.h"
+#endif
+
 #if LV_USE_OBSERVER
 
 /*********************
@@ -56,6 +60,9 @@ typedef union {
  * The Subject (an observable value)
  */
 struct _lv_subject_t {
+#if LV_USE_EXT_DATA
+    lv_ext_data_t ext_data;
+#endif
     lv_ll_t subs_ll;                     /**< Subscribers */
     lv_subject_value_t value;            /**< Current value */
     lv_subject_value_t prev_value;       /**< Previous value */
@@ -79,6 +86,27 @@ typedef void (*lv_observer_cb_t)(lv_observer_t * observer, lv_subject_t * subjec
  * GLOBAL PROTOTYPES
  **********************/
 
+#if LV_USE_EXT_DATA
+/**
+ * @brief Attaches external user data to an integer Subject with lifecycle management
+ *
+ * Associates arbitrary user-defined data with an LVGL observer and registers a destructor
+ * callback that will be automatically invoked when the observer is deleted. This enables:
+ * - Safe resource cleanup through the destructor mechanism
+ * - Contextual data storage for observer callbacks
+ * - Proper memory management for observer-related resources
+ *
+ * @param subject    pointer to Subject
+ * @param data       User-defined data pointer to associate
+ * @param free_cb    Cleanup function called when:
+ *                   - Observer is explicitly deleted
+ *                   - Observed object is deleted
+ *                   - New data replaces current association
+ *                   NULL indicates no cleanup required
+ */
+void lv_subject_set_external_data(lv_subject_t * subject, void * data, void (* free_cb)(void * data));
+#endif
+
 /**
  * Initialize an integer-type Subject.
  * @param subject   pointer to Subject

src/display/lv_display.c

@@ -76,7 +76,10 @@ lv_display_t * lv_display_create(int32_t hor_res, int32_t ver_res)
     disp->antialiasing     = LV_COLOR_DEPTH > 8 ? 1 : 0;
     disp->dpi              = LV_DPI_DEF;
     disp->color_format = LV_COLOR_FORMAT_NATIVE;
-
+#if LV_USE_EXT_DATA
+    disp->ext_data.free_cb = NULL;
+    disp->ext_data.data = NULL;
+#endif
 
 #if defined(LV_DRAW_SW_DRAW_UNIT_CNT) && (LV_DRAW_SW_DRAW_UNIT_CNT != 0)
     disp->tile_cnt = LV_DRAW_SW_DRAW_UNIT_CNT;
@@ -227,6 +230,13 @@ void lv_display_delete(lv_display_t * disp)
     if(disp->layer_deinit) disp->layer_deinit(disp, disp->layer_head);
     lv_free(disp->layer_head);
 
+#if LV_USE_EXT_DATA
+    if(disp->ext_data.free_cb) {
+        disp->ext_data.free_cb(disp->ext_data.data);
+        disp->ext_data.data = NULL;
+    }
+#endif
+
     lv_free(disp);
 
     if(was_default) lv_display_set_default(lv_ll_get_head(disp_ll_p));
@@ -1273,6 +1283,19 @@ int32_t lv_display_dpx(const lv_display_t * disp, int32_t n)
     return LV_DPX_CALC(lv_display_get_dpi(disp), n);
 }
 
+#if LV_USE_EXT_DATA
+void lv_display_set_external_data(lv_display_t * disp, void * data, void (* free_cb)(void * data))
+{
+    if(!disp) {
+        LV_LOG_WARN("Can't attach external user data and destructor callback to a NULL display");
+        return;
+    }
+
+    disp->ext_data.data = data;
+    disp->ext_data.free_cb = free_cb;
+}
+#endif
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/

src/display/lv_display.h

@@ -732,6 +732,22 @@ int32_t lv_dpx(int32_t n);
  */
 int32_t lv_display_dpx(const lv_display_t * disp, int32_t n);
 
+#if LV_USE_EXT_DATA
+/**
+ * @brief Attaches external user data and destructor callback to a display
+ *
+ * Associates custom user data with an LVGL display and specifies a destructor function
+ * that will be automatically invoked when the display is deleted to properly clean up
+ * the associated resources.
+ *
+ * @param disp       Pointer to a display
+ * @param data       User-defined data pointer to associate with the display
+ * @param free_cb    Callback function for cleaning up data when display is deleted.
+ *                   Receives data as parameter. NULL means no cleanup required.
+ */
+void lv_display_set_external_data(lv_display_t * disp, void * data, void (* free_cb)(void * data));
+#endif
+
 #ifdef __cplusplus
 } /*extern "C"*/
 #endif

src/display/lv_display_private.h

@@ -22,6 +22,10 @@ extern "C" {
 #include "../debugging/sysmon/lv_sysmon_private.h"
 #endif
 
+#if LV_USE_EXT_DATA
+#include "../lvgl_private.h"
+#endif
+
 /*********************
  *      DEFINES
  *********************/
@@ -34,7 +38,9 @@ extern "C" {
  **********************/
 
 struct _lv_display_t {
-
+#if LV_USE_EXT_DATA
+    lv_ext_data_t ext_data;
+#endif
     /*---------------------
      * Resolution
      *--------------------*/

src/indev/lv_indev.c

@@ -142,6 +142,10 @@ lv_indev_t * lv_indev_create(void)
     indev->gesture_min_velocity = LV_INDEV_DEF_GESTURE_MIN_VELOCITY;
     indev->rotary_sensitivity  = LV_INDEV_DEF_ROTARY_SENSITIVITY;
     indev->key_remap_cb         = NULL;
+#if LV_USE_EXT_DATA
+    indev->ext_data.free_cb = NULL;
+    indev->ext_data.data = NULL;
+#endif
 
 #if LV_USE_GESTURE_RECOGNITION
     lv_indev_gesture_init(indev);
@@ -163,6 +167,14 @@ void lv_indev_delete(lv_indev_t * indev)
 
     /*Remove the input device from the list*/
     lv_ll_remove(indev_ll_head, indev);
+
+#if LV_USE_EXT_DATA
+    if(indev->ext_data.free_cb) {
+        indev->ext_data.free_cb(indev->ext_data.data);
+        indev->ext_data.data = NULL;
+    }
+#endif
+
     /*Free the memory of the input device*/
     lv_free(indev);
 }
@@ -685,6 +697,19 @@ void lv_indev_set_key_remap_cb(lv_indev_t * indev, lv_indev_key_remap_cb_t remap
     indev->key_remap_cb = remap_cb;
 }
 
+#if LV_USE_EXT_DATA
+void lv_indev_set_external_data(lv_indev_t * indev, void * data, void (* free_cb)(void * data))
+{
+    if(!indev) {
+        LV_LOG_WARN("Can't attach external user data and free_cb callback to a NULL indev");
+        return;
+    }
+
+    indev->ext_data.data = data;
+    indev->ext_data.free_cb = free_cb;
+}
+#endif
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/

src/indev/lv_indev.h

@@ -452,6 +452,22 @@ lv_result_t lv_indev_send_event(lv_indev_t * indev, lv_event_code_t code, void *
  */
 void lv_indev_set_key_remap_cb(lv_indev_t * indev, lv_indev_key_remap_cb_t remap_cb);
 
+#if LV_USE_EXT_DATA
+/**
+ * @brief Attaches external user data and destructor callback to an indev
+ *
+ * Associates custom user data with an LVGL indev and specifies a destructor function
+ * that will be automatically invoked when the indev is deleted to properly clean up
+ * the associated resources.
+ *
+ * @param indev      Pointer to an indev
+ * @param data       User-defined data pointer to associate with the indev
+ * @param free_cb    Callback function for cleaning up ext_data when indev is deleted.
+ *                   Receives ext_data as parameter. NULL means no cleanup required.
+ */
+void lv_indev_set_external_data(lv_indev_t * indev, void * data, void (* free_cb)(void * data));
+#endif
+
 /**********************
  *      MACROS
  **********************/

src/indev/lv_indev_private.h

@@ -18,6 +18,10 @@ extern "C" {
 #include "lv_indev_scroll.h"
 #include "lv_indev_gesture.h"
 
+#if LV_USE_EXT_DATA
+#include "../lvgl_private.h"
+#endif
+
 /*********************
  *      DEFINES
  *********************/
@@ -28,6 +32,9 @@ extern "C" {
  **********************/
 
 struct _lv_indev_t {
+#if LV_USE_EXT_DATA
+    lv_ext_data_t ext_data;
+#endif
     /** Input device type*/
     lv_indev_type_t type;
 

src/lv_conf_internal.h

@@ -4503,6 +4503,15 @@
     #endif
 #endif
 
+/** Enable or disable for external data and destructor function */
+#ifndef LV_USE_EXT_DATA
+    #ifdef CONFIG_LV_USE_EXT_DATA
+        #define LV_USE_EXT_DATA CONFIG_LV_USE_EXT_DATA
+    #else
+        #define LV_USE_EXT_DATA   0
+    #endif
+#endif
+
 /*=====================
 * BUILD OPTIONS
 *======================*/

src/lvgl_private.h

@@ -23,6 +23,13 @@ extern "C" {
  *      TYPEDEFS
  **********************/
 
+#if LV_USE_EXT_DATA
+typedef struct {
+    void * data;
+    void (* free_cb)(void * data);
+} lv_ext_data_t;
+#endif
+
 /**********************
  * GLOBAL PROTOTYPES
  **********************/

src/misc/lv_anim.c

@@ -114,6 +114,10 @@ void lv_anim_init(lv_anim_t * a)
     a->repeat_cnt = 1;
     a->path_cb = lv_anim_path_linear;
     a->early_apply = 1;
+#if LV_USE_EXT_DATA
+    a->ext_data.free_cb = NULL;
+    a->ext_data.data = NULL;
+#endif
 }
 
 lv_anim_t * lv_anim_start(const lv_anim_t * a)
@@ -555,6 +559,19 @@ void lv_anim_resume(lv_anim_t * a)
     a->run_round = state.anim_run_round;
 }
 
+#if LV_USE_EXT_DATA
+void lv_anim_set_external_data(lv_anim_t * anim, void * data, void (* free_cb)(void * data))
+{
+    if(!a) {
+        LV_LOG_WARN("Can't attach external user data and destructor callback to a NULL animation");
+        return;
+    }
+
+    anim->ext_data.data = data;
+    anim->ext_data.free_cb = free_cb;
+}
+#endif
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/
@@ -680,6 +697,12 @@ static void anim_completed_handler(lv_anim_t * a)
         /*Call the callback function at the end*/
         if(a->completed_cb != NULL) a->completed_cb(a);
         if(a->deleted_cb != NULL) a->deleted_cb(a);
+#if LV_USE_EXT_DATA
+        if(a->ext_data.free_cb) {
+            a->ext_data.free_cb(a->ext_data.data);
+            a->ext_data.data = NULL;
+        }
+#endif
         lv_free(a);
     }
     /*If the animation is not deleted then restart it*/
@@ -797,6 +820,12 @@ static bool remove_concurrent_anims(const lv_anim_t * a_current)
             /*|| (a->custom_exec_cb && a->custom_exec_cb == a_current->custom_exec_cb)*/)) {
             lv_ll_remove(anim_ll_p, a);
             if(a->deleted_cb != NULL) a->deleted_cb(a);
+#if LV_USE_EXT_DATA
+            if(a->ext_data.free_cb) {
+                a->ext_data.free_cb(a->ext_data.data);
+                a->ext_data.data = NULL;
+            }
+#endif
             lv_free(a);
             /*Read by `anim_timer`. It need to know if a delete occurred in the linked list*/
             anim_mark_list_change();
@@ -818,5 +847,11 @@ static void remove_anim(void * a)
     lv_anim_t * anim = a;
     lv_ll_remove(anim_ll_p, a);
     if(anim->deleted_cb != NULL) anim->deleted_cb(anim);
+#if LV_USE_EXT_DATA
+    if(anim->ext_data.free_cb) {
+        anim->ext_data.free_cb(anim->ext_data.data);
+        anim->ext_data.data = NULL;
+    }
+#endif
     lv_free(a);
 }

src/misc/lv_anim.h

@@ -19,6 +19,10 @@ extern "C" {
 #include "lv_timer.h"
 #include "lv_ll.h"
 
+#if LV_USE_EXT_DATA
+#include "../lvgl_private.h"
+#endif
+
 /*********************
  *      DEFINES
  *********************/
@@ -122,6 +126,9 @@ typedef struct {
 
 /** Describes an animation*/
 struct _lv_anim_t {
+#if LV_USE_EXT_DATA
+    lv_ext_data_t ext_data;
+#endif
     void * var;                               /**< Variable (Widget or other user-provided object) to animate */
     lv_anim_exec_xcb_t exec_cb;               /**< Function to execute to animate */
     lv_anim_custom_exec_cb_t custom_exec_cb;  /**< Function to execute to animate,
@@ -555,6 +562,25 @@ int32_t lv_anim_path_step(const lv_anim_t * a);
  */
 int32_t lv_anim_path_custom_bezier3(const lv_anim_t * a);
 
+#if LV_USE_EXT_DATA
+/**
+ * @brief Associates external user data with an animation instance
+ *
+ * Attaches arbitrary user-defined data to an LVGL animation object along with an optional
+ * destructor callback that will be automatically invoked when the animation completes
+ * or is deleted, enabling proper resource cleanup.
+ *
+ * @param anim       Pointer to the animation object to configure
+ * @param data       User-defined data pointer to associate
+ * @param free_cb    Cleanup callback that receives ext_data when:
+ *                   - Animation completes naturally
+ *                   - Animation is deleted prematurely
+ *                   - New data replaces current association
+ *                   NULL indicates no cleanup required
+ */
+void lv_anim_set_external_data(lv_anim_t * anim, void * data, void (* free_cb)(void * data));
+#endif
+
 /**********************
  *   GLOBAL VARIABLES
  **********************/

src/misc/lv_event.c

@@ -54,6 +54,19 @@ static lv_event_dsc_t ** event_array_at(lv_event_list_t * list, uint32_t index);
  *   GLOBAL FUNCTIONS
  **********************/
 
+#if LV_USE_EXT_DATA
+void lv_event_desc_set_external_data(lv_event_dsc_t * dsc, void * data, void (* free_cb)(void * data))
+{
+    if(!dsc) {
+        LV_LOG_WARN("Can't attach external user data and destructor callback to a NULL event descriptor");
+        return;
+    }
+
+    dsc->ext_data.data = data;
+    dsc->ext_data.free_cb = free_cb;
+}
+#endif
+
 void lv_event_push(lv_event_t * e)
 {
     /*Build a simple linked list from the objects used in the events
@@ -118,6 +131,9 @@ lv_result_t lv_event_send(lv_event_list_t * list, lv_event_t * e, bool preproces
         lv_event_code_t filter = dsc->filter & ~LV_EVENT_PREPROCESS;
         if(filter == LV_EVENT_ALL || filter == e->code) {
             e->user_data = dsc->user_data;
+#if LV_USE_EXT_DATA
+            e->ext_data.data = dsc->ext_data.data;
+#endif
             dsc->cb(e);
             if(e->stop_processing) break;
 
@@ -149,6 +165,10 @@ lv_event_dsc_t * lv_event_add(lv_event_list_t * list, lv_event_cb_t cb, lv_event
     dsc->cb = cb;
     dsc->filter = filter;
     dsc->user_data = user_data;
+#if LV_USE_EXT_DATA
+    dsc->ext_data.free_cb = NULL;
+    dsc->ext_data.data = NULL;
+#endif
 
     if(event_array_size(list) == 0) {
         /*event list hasn't been initialized.*/
@@ -168,6 +188,12 @@ bool lv_event_remove_dsc(lv_event_list_t * list, lv_event_dsc_t * dsc)
     for(uint32_t i = 0; i < size; i++) {
         lv_event_dsc_t * event = *event_array_at(list, i);
         if(event == dsc) {
+#if LV_USE_EXT_DATA
+            if(dsc->ext_data.free_cb) {
+                dsc->ext_data.free_cb(dsc->ext_data.data);
+                dsc->ext_data.data = NULL;
+            }
+#endif
             event_mark_deleting(list, event);
             cleanup_event_list(list);
             return true;
@@ -208,6 +234,12 @@ bool lv_event_remove(lv_event_list_t * list, uint32_t index)
     LV_ASSERT_NULL(list);
     lv_event_dsc_t * dsc = lv_event_get_dsc(list, index);
     if(dsc == NULL) return false;
+#if LV_USE_EXT_DATA
+    if(dsc->ext_data.free_cb) {
+        dsc->ext_data.free_cb(dsc->ext_data.data);
+        dsc->ext_data.data = NULL;
+    }
+#endif
     event_mark_deleting(list, dsc);
     cleanup_event_list(list);
     return true;
@@ -217,8 +249,17 @@ void lv_event_remove_all(lv_event_list_t * list)
 {
     LV_ASSERT_NULL(list);
     const uint32_t size = event_array_size(list);
-    for(uint32_t i = 0; i < size; i++)
+    for(uint32_t i = 0; i < size; i++) {
+#if LV_USE_EXT_DATA
+        lv_event_dsc_t * dsc = lv_event_get_dsc(list, i);
+        if(dsc && dsc->ext_data.free_cb) {
+            dsc->ext_data.free_cb(dsc->ext_data.data);
+            dsc->ext_data.data = NULL;
+        }
+#endif
         event_mark_deleting(list, *event_array_at(list, i));
+    }
+
     cleanup_event_list(list);
 }
 

src/misc/lv_event.h

@@ -245,6 +245,19 @@ uint32_t lv_event_register_id(void);
  */
 const char * lv_event_code_get_name(lv_event_code_t code);
 
+#if LV_USE_EXT_DATA
+/**
+ * Set external data and its destructor for an event descriptor.
+ * This allows associating custom data with an event callback that will be automatically cleaned up
+ * when the event descriptor is removed or destroyed.
+ * @param dsc         pointer to an event descriptor (from lv_obj_add_event_cb)
+ * @param data        pointer to the external data to associate with the event descriptor
+ * @param free_cb     function pointer to a destructor that will be called to clean up the external data.
+ *                    The destructor will receive the data pointer as its parameter.
+ */
+void lv_event_desc_set_external_data(lv_event_dsc_t * dsc, void * data, void (* free_cb)(void * data));
+#endif
+
 /**********************
  *      MACROS
  **********************/

src/misc/lv_event_private.h

@@ -16,6 +16,10 @@ extern "C" {
 
 #include "lv_event.h"
 
+#if LV_USE_EXT_DATA
+#include "../lvgl_private.h"
+#endif
+
 /*********************
  *      DEFINES
  *********************/
@@ -25,6 +29,9 @@ extern "C" {
  **********************/
 
 struct _lv_event_dsc_t {
+#if LV_USE_EXT_DATA
+    lv_ext_data_t ext_data;
+#endif
     lv_event_cb_t cb;
     void * user_data;
     uint32_t filter;
@@ -41,6 +48,9 @@ struct _lv_event_t {
     uint8_t stop_processing : 1;
     uint8_t stop_bubbling : 1;
     uint8_t stop_trickling : 1;
+#if LV_USE_EXT_DATA
+    lv_ext_data_t ext_data;
+#endif
 };
 
 

src/misc/lv_timer.c

@@ -177,6 +177,10 @@ lv_timer_t * lv_timer_create(lv_timer_cb_t timer_xcb, uint32_t period, void * us
     new_timer->last_run = lv_tick_get();
     new_timer->user_data = user_data;
     new_timer->auto_delete = true;
+#if LV_USE_EXT_DATA
+    new_timer->ext_data.free_cb = NULL;
+    new_timer->ext_data.data = NULL;
+#endif
 
     state.timer_created = true;
 
@@ -196,6 +200,13 @@ void lv_timer_delete(lv_timer_t * timer)
     lv_ll_remove(timer_ll_p, timer);
     state.timer_deleted = true;
 
+#if LV_USE_EXT_DATA
+    if(timer->ext_data.free_cb) {
+        timer->ext_data.free_cb(timer->ext_data.data);
+        timer->ext_data.data = NULL;
+    }
+#endif
+
     lv_free(timer);
 }
 
@@ -301,6 +312,19 @@ bool lv_timer_get_paused(lv_timer_t * timer)
     return timer->paused;
 }
 
+#if LV_USE_EXT_DATA
+void lv_timer_set_external_data(lv_timer_t * timer, void * data, void (* free_cb)(void * data))
+{
+    if(!timer) {
+        LV_LOG_WARN("Can't attach external user data and destructor callback to a NULL timer");
+        return;
+    }
+
+    timer->ext_data.data = data;
+    timer->ext_data.free_cb = free_cb;
+}
+#endif
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/

src/misc/lv_timer.h

@@ -196,6 +196,22 @@ void * lv_timer_get_user_data(lv_timer_t * timer);
  */
 bool lv_timer_get_paused(lv_timer_t * timer);
 
+#if LV_USE_EXT_DATA
+/**
+ * @brief Attaches external user data and destructor callback to a timer object
+ *
+ * Associates custom user data with an LVGL timer and specifies a destructor function
+ * that will be automatically invoked when the timer is deleted to properly clean up
+ * the associated resources.
+ *
+ * @param timer      Pointer to the timer object
+ * @param data       User-defined data pointer to associate with the timer
+ * @param destructor Callback function for cleaning up ext_data when timer is deleted.
+ *                   Receives ext_data as parameter. NULL means no cleanup required.
+ */
+void lv_timer_set_external_data(lv_timer_t * timer, void * data, void (* free_cb)(void * data));
+#endif
+
 /**********************
  *      MACROS
  **********************/

src/misc/lv_timer_private.h

@@ -16,6 +16,10 @@ extern "C" {
 
 #include "lv_timer.h"
 
+#if LV_USE_EXT_DATA
+#include "../lvgl_private.h"
+#endif
+
 /*********************
  *      DEFINES
  *********************/
@@ -28,6 +32,9 @@ extern "C" {
  * Descriptor of a lv_timer
  */
 struct _lv_timer_t {
+#if LV_USE_EXT_DATA
+    lv_ext_data_t ext_data;
+#endif
     uint32_t period;           /**< How often the timer should run */
     uint32_t last_run;         /**< Last time the timer ran */
     lv_timer_cb_t timer_cb;    /**< Timer function */

src/themes/default/lv_theme_default.c

@@ -667,6 +667,10 @@ lv_theme_t * lv_theme_default_init(lv_display_t * disp, lv_color_t color_primary
     theme->base.font_large = font;
     theme->base.apply_cb = theme_apply;
     theme->base.flags = dark ? MODE_DARK : 0;
+#if LV_USE_EXT_DATA
+    theme->base.ext_data.free_cb = NULL;
+    theme->base.ext_data.data = NULL;
+#endif
 
     style_init(theme);
 
@@ -711,6 +715,12 @@ void lv_theme_default_deinit(void)
                 lv_style_reset(theme_styles + i);
             }
         }
+#if LV_USE_EXT_DATA
+        if(theme->base.ext_data.free_cb) {
+            theme->base.ext_data.free_cb(theme->base.ext_data.data);
+            theme->base.ext_data.data = NULL;
+        }
+#endif
         lv_free(theme_def);
         theme_def = NULL;
     }

src/themes/lv_theme.c

@@ -113,6 +113,19 @@ lv_color_t lv_theme_get_color_secondary(lv_obj_t * obj)
     return th ? th->color_secondary : lv_palette_main(LV_PALETTE_BLUE);
 }
 
+#if LV_USE_EXT_DATA
+void lv_theme_set_external_data(lv_theme_t * theme, void * data, void (* free_cb)(void * data))
+{
+    if(!theme) {
+        LV_LOG_WARN("Can't attach external user data and destructor callback to a NULL theme");
+        return;
+    }
+
+    theme->ext_data.data = data;
+    theme->ext_data.free_cb = free_cb;
+}
+#endif
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/

src/themes/lv_theme.h

@@ -113,6 +113,22 @@ lv_color_t lv_theme_get_color_secondary(lv_obj_t * obj);
  */
 void lv_theme_delete(lv_theme_t * theme);
 
+#if LV_USE_EXT_DATA
+/**
+ * @brief Attaches external user data and destructor callback to the theme
+ *
+ * Associates custom user data with an LVGL theme and specifies a destructor function
+ * that will be automatically invoked when the theme is deleted to properly clean up
+ * the associated resources.
+ *
+ * @param theme      Pointer to theme which callback should be set
+ * @param data       User-defined data pointer to associate with the theme
+ * @param free_cb    Callback function for cleaning up ext_data when theme is deleted.
+ *                   Receives ext_data as parameter. NULL means no cleanup required.
+ */
+void lv_theme_set_external_data(lv_theme_t * theme, void * data, void (* free_cb)(void * data));
+#endif
+
 /**********************
  *    MACROS
  **********************/

src/themes/lv_theme_private.h

@@ -16,6 +16,10 @@ extern "C" {
 
 #include "lv_theme.h"
 
+#if LV_USE_EXT_DATA
+#include "../lvgl_private.h"
+#endif
+
 /*********************
  *      DEFINES
  *********************/
@@ -25,6 +29,9 @@ extern "C" {
  **********************/
 
 struct _lv_theme_t {
+#if LV_USE_EXT_DATA
+    lv_ext_data_t ext_data;
+#endif
     lv_theme_apply_cb_t apply_cb;
     lv_theme_t * parent;            /**< Apply the current theme's style on top of this theme. */
     void * user_data;

src/themes/mono/lv_theme_mono.c

@@ -198,6 +198,10 @@ lv_theme_t * lv_theme_mono_init(lv_display_t * disp, bool dark_bg, const lv_font
     theme->base.font_normal = LV_FONT_DEFAULT;
     theme->base.font_large = LV_FONT_DEFAULT;
     theme->base.apply_cb = theme_apply;
+#if LV_USE_EXT_DATA
+    theme->base.ext_data.free_cb = NULL;
+    theme->base.ext_data.data = NULL;
+#endif
 
     style_init(theme, dark_bg, font);
 
@@ -237,6 +241,12 @@ void lv_theme_mono_deinit(void)
                 lv_style_reset(theme_styles + i);
             }
         }
+#if LV_USE_EXT_DATA
+        if(theme->base.ext_data.free_cb) {
+            theme->base.ext_data.free_cb(theme->base.ext_data.data);
+            theme->base.ext_data.data = NULL;
+        }
+#endif
         lv_free(theme_def);
         theme_def = NULL;
     }

src/themes/simple/lv_theme_simple.c

@@ -159,6 +159,10 @@ lv_theme_t * lv_theme_simple_init(lv_display_t * disp)
     theme->base.font_normal = LV_FONT_DEFAULT;
     theme->base.font_large = LV_FONT_DEFAULT;
     theme->base.apply_cb = theme_apply;
+#if LV_USE_EXT_DATA
+    theme->base.ext_data.free_cb = NULL;
+    theme->base.ext_data.data = NULL;
+#endif
 
     style_init(theme);
 
@@ -198,6 +202,12 @@ void lv_theme_simple_deinit(void)
                 lv_style_reset(theme_styles + i);
             }
         }
+#if LV_USE_EXT_DATA
+        if(theme->base.ext_data.free_cb) {
+            theme->base.ext_data.free_cb(theme->base.ext_data.data);
+            theme->base.ext_data.data = NULL;
+        }
+#endif
         lv_free(theme_def);
         theme_def = NULL;
     }