tangara-fw/lib/luavgl/src/obj.c

#include "core/lv_group.h"
#include "core/lv_obj.h"
#include "luavgl.h"
#include "private.h"

/* extended feature for object */
#include "event.c"
#include "style.c"
#include "widgets/widgets.c"

static int luavgl_anim_create(lua_State *L);
static int luavgl_obj_delete(lua_State *L);

static void _lv_obj_set_align(void *obj, lua_State *L) {
  if (lua_isinteger(L, -1)) {
    lv_obj_align(obj, lua_tointeger(L, -1), 0, 0);
    return;
  }

  if (!lua_istable(L, -1)) {
    luaL_argerror(L, -1, "should be table.");
    debug("para should be table.");
    return;
  }

  lua_getfield(L, -1, "type");
  lv_align_t align = lua_tointeger(L, -1);
  lua_pop(L, 1);

  lua_getfield(L, -1, "x_ofs");
  lv_coord_t x_ofs = lua_tointeger(L, -1);
  lua_pop(L, 1);

  lua_getfield(L, -1, "y_ofs");
  lv_coord_t y_ofs = lua_tointeger(L, -1);
  lua_pop(L, 1);

  lv_obj_align(obj, align, x_ofs, y_ofs);
}

/**
 * @brief Set obj properties based on property table on stack top
 *
 * Internally used.
 */
static inline void luavgl_setup_obj(lua_State *L, lv_obj_t *obj) {
  luavgl_iterate(L, -1, luavgl_obj_set_property_kv, obj);
}

static void obj_delete_cb(lv_event_t *e) {
  lua_State *L = e->user_data;
  lua_pushlightuserdata(L, e->current_target);
  lua_rawget(L, LUA_REGISTRYINDEX);
  if (lua_isnoneornil(L, -1)) {
    goto pop_exit;
  }

  luavgl_obj_t *lobj = luavgl_to_lobj(L, -1);
  if (lobj->lua_created) {
    // The underlying object is now gone, so don't keep a reference to it.
    lobj->obj = NULL;
    // Ensure there's no dangling reference in the registry either.
    lua_pushlightuserdata(L, e->current_target);
    lua_pushnil(L);
    lua_rawset(L, LUA_REGISTRYINDEX);

    goto pop_exit;
  }

  luavgl_obj_delete(L);
  return;

pop_exit:
  lua_pop(L, 1);
  return;
}

/**
 * get the obj userdata and uservalue, if uservalue is not a table, then add
 * one. result stack: table(from uservalue)
 * return uservalue type: LUA_TTABLE
 */
LUALIB_API int luavgl_obj_getuserdatauv(lua_State *L, int idx) {
  int type = lua_getuservalue(L, idx);
  if (type == LUA_TTABLE)
    return type;

  lua_pop(L, 1);
  /* initial element: 1 */
  lua_createtable(L, 0, 1);

#if 0 /* reserved slot, not used for now */
  lua_pushinteger(L, 1);
  lua_pushnil(L);
  lua_rawset(L, -3);
#endif
  lua_pushvalue(L, -1); /* leave one on stack */
  lua_setuservalue(L, idx > 0 ? idx : idx - 3);
  return LUA_TTABLE;
}

static int luavgl_obj_create(lua_State *L) {
  return luavgl_obj_create_helper(L, lv_obj_create);
}

static int luavgl_obj_delete(lua_State *L) {
  luavgl_obj_t *lobj;

  /**
   * Some widget may create child obj that doesn't belong to lua. Ignore them
   * and report no error.
   */
  if (!(lobj = lua_touserdata(L, -1))) {
    return 0;
  }

  if (lobj->obj == NULL) {
    /* could be already deleted, but not gc'ed */
    return 0;
  }

  uint32_t cnt = lv_obj_get_child_cnt(lobj->obj);

  for (int i = cnt - 1; i >= 0; i--) {
    lv_obj_t *child = lv_obj_get_child(lobj->obj, i);
    lua_checkstack(L, 2);
    lua_pushlightuserdata(L, child);
    lua_rawget(L, LUA_REGISTRYINDEX);
    if (lua_isnoneornil(L, -1)) {
      continue;
    }

    luavgl_obj_delete(L);
  }

  luavgl_obj_remove_event_all(L, lobj);

  /* delete obj firstly, then cleanup memory */
  if (lobj->lua_created) {
    lv_obj_del(lobj->obj);
  }

  lua_checkstack(L, 2);
  /* remove userdata from registry. */
  lua_pushlightuserdata(L, lobj->obj);
  lua_pushnil(L);
  lua_rawset(L, LUA_REGISTRYINDEX);

  debug("delete obj: %p\n", lobj->obj);
  lobj->obj = NULL;

  lua_pop(L, 1); /* remove the userdata para */
  return 0;
}

static int luavgl_obj_clean(lua_State *L) {
  luavgl_obj_t *lobj = luavgl_to_lobj(L, -1);
  if (lobj == NULL || lobj->obj == NULL)
    return 0;

  lv_obj_t *obj = lobj->obj;
  uint32_t cnt = lv_obj_get_child_cnt(obj);

  for (int i = cnt - 1; i >= 0; i--) {
    lv_obj_t *child = lv_obj_get_child(obj, i);

    lua_checkstack(L, 2);
    lua_pushlightuserdata(L, child);
    lua_rawget(L, LUA_REGISTRYINDEX);
    luavgl_obj_delete(L);
  }

  lua_pop(L, 1); /* remove the userdata para */
  return 0;
}

static int luavgl_obj_set(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);

  if (!lua_istable(L, -1)) {
    luaL_error(L, "expect a table on 2nd para.");
    return 0;
  }

  luavgl_setup_obj(L, obj);
  return 0;
}

/**
 * obj:align_to({base=base, type=type, x_ofs=0, y_ofs=0})
 */
static int luavgl_obj_align_to(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);

  if (!lua_istable(L, 2)) {
    debug("para should be table.");
    return luaL_argerror(L, 2, "should be table.");
  }

  lua_getfield(L, 2, "type");
  lv_align_t align = lua_tointeger(L, -1);
  lua_pop(L, 1);

  lua_getfield(L, 2, "base");
  lv_obj_t *base = luavgl_to_lobj(L, -1)->obj;
  lua_pop(L, 1);
  if (base == NULL) {
    debug("base is not lua obj");
    return luaL_argerror(L, -1, "base is not lua obj");
  }

  lua_getfield(L, 2, "x_ofs");
  lv_coord_t x_ofs = lua_tointeger(L, -1);
  lua_pop(L, 1);

  lua_getfield(L, 2, "y_ofs");
  lv_coord_t y_ofs = lua_tointeger(L, -1);
  lua_pop(L, 1);

  lv_obj_align_to(obj, base, align, x_ofs, y_ofs);
  return 0;
}

static int luavgl_obj_set_parent(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_obj_t *parent = luavgl_to_obj(L, 2);
  lv_obj_set_parent(obj, parent);
  return 0;
}

static int luavgl_obj_get_screen(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_obj_t *screen = lv_obj_get_screen(obj);

  /* check if userdata is added to this obj, so lua can access it. */
  lua_pushlightuserdata(L, screen);
  lua_rawget(L, LUA_REGISTRYINDEX);

  if (lua_isnil(L, -1)) {
    /* create luavgl object and attach screen on it. */
    luavgl_obj_t *lobj = luavgl_add_lobj(L, screen);
    /* mark it's non-lua created, thus cannot be deleted by lua */
    lobj->lua_created = false;
  }

  return 1;
}

static int luavgl_obj_get_parent(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_obj_t *parent = lv_obj_get_parent(obj);

  /* check if userdata is added to this obj, so lua can access it. */
  lua_pushlightuserdata(L, parent);
  lua_rawget(L, LUA_REGISTRYINDEX);
  if (lua_isnil(L, -1)) {
    /* create luavgl object and attach screen on it. */
    luavgl_obj_t *lobj = luavgl_add_lobj(L, parent);
    /* mark it's non-lua created, thus cannot be deleted by lua */
    lobj->lua_created = false;
  }

  return 1;
}

static int luavgl_obj_set_get_parent(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  if (!lua_isnoneornil(L, 2)) {
    lv_obj_t *parent = luavgl_to_obj(L, 2);
    lv_obj_set_parent(obj, parent);
  }

  return luavgl_obj_get_parent(L);
}

static int luavgl_obj_get_child(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);

  int id = luavgl_tointeger(L, 2);
  lv_obj_t *child = lv_obj_get_child(obj, id);
  if (child == NULL) {
    lua_pushnil(L);
    return 1;
  }

  /* check if userdata is added to this obj, so lua can access it. */
  lua_pushlightuserdata(L, child);
  lua_rawget(L, LUA_REGISTRYINDEX);
  if (lua_isnil(L, -1)) {
    luavgl_add_lobj(L, child)->lua_created = false;
  }

  return 1;
}

static int luavgl_obj_get_child_cnt(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lua_pushinteger(L, lv_obj_get_child_cnt(obj));
  return 1;
}

static int luavgl_obj_get_state(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_state_t state = lv_obj_get_state(obj);
  lua_pushinteger(L, state);

  return 1;
}

/**
 * obj:scroll_to({x=10})
 * obj:scroll_to({x=10, anim=true})
 * obj:scroll_to({x=10, y=100, anim=false})
 */
static int luavgl_obj_scroll_to(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);

  if (!lua_istable(L, -1)) {
    luaL_argerror(L, -1, "should be table {x=0,y=0,anim=true}");
  }

  lua_getfield(L, -1, "anim");
  bool anim = luavgl_tointeger(L, -1);
  lua_pop(L, 1);

  lv_coord_t v;
  lua_getfield(L, -1, "x");
  if (!lua_isnil(L, -1)) {
    v = lua_tointeger(L, -1);
    lv_obj_scroll_to_x(obj, v, anim ? LV_ANIM_ON : LV_ANIM_OFF);
  }
  lua_pop(L, 1);

  lua_getfield(L, -1, "y");
  if (!lua_isnil(L, -1)) {
    v = lua_tointeger(L, -1);
    lv_obj_scroll_to_x(obj, v, anim ? LV_ANIM_ON : LV_ANIM_OFF);
  }
  lua_pop(L, 1);

  return 0;
}

static int luavgl_obj_is_visible(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lua_pushboolean(L, lv_obj_is_visible(obj));

  return 1;
}

static int luavgl_obj_add_flag(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_obj_flag_t flag = lua_tointeger(L, 2);
  lv_obj_add_flag(obj, flag);

  return 0;
}

static int luavgl_obj_clear_flag(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_obj_flag_t flag = lua_tointeger(L, 2);
  lv_obj_clear_flag(obj, flag);

  return 0;
}

static int luavgl_obj_add_state(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_state_t state = lua_tointeger(L, 2);
  lv_obj_add_state(obj, state);
  return 0;
}

static int luavgl_obj_clear_state(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_state_t state = lua_tointeger(L, 2);
  lv_obj_clear_state(obj, state);
  return 0;
}

/**
 * obj:scroll_by(x, y, anim_en)
 */
static int luavgl_obj_scroll_by(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  int x = luavgl_tointeger(L, 2);
  int y = luavgl_tointeger(L, 3);
  int anim_en = luavgl_tointeger(L, 4);

  lv_obj_scroll_by(obj, x, y, anim_en);
  return 0;
}

static int luavgl_obj_scroll_by_bounded(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  int dx = luavgl_tointeger(L, 2);
  int dy = luavgl_tointeger(L, 3);
  int anim_en = luavgl_tointeger(L, 4);

  lv_obj_scroll_by_bounded(obj, dx, dy, anim_en);
  return 0;
}

static int luavgl_obj_scroll_to_view(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  int anim_en = luavgl_tointeger(L, 2);

  lv_obj_scroll_to_view(obj, anim_en);
  return 0;
}

static int luavgl_obj_scroll_to_view_recursive(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  int anim_en = luavgl_tointeger(L, 2);

  lv_obj_scroll_to_view_recursive(obj, anim_en);
  return 0;
}

static int luavgl_obj_scroll_by_raw(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  int x = luavgl_tointeger(L, 2);
  int y = luavgl_tointeger(L, 3);

  _lv_obj_scroll_by_raw(obj, x, y);
  return 0;
}

static int luavgl_obj_is_scrolling(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lua_pushboolean(L, lv_obj_is_scrolling(obj));
  return 1;
}

static int luavgl_obj_scrollbar_invalidate(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_obj_scrollbar_invalidate(obj);
  return 0;
}

static int luavgl_obj_readjust_scroll(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  int anim_en = luavgl_tointeger(L, 2);
  lv_obj_readjust_scroll(obj, anim_en);
  return 0;
}

static int luavgl_obj_is_editable(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lua_pushboolean(L, lv_obj_is_editable(obj));
  return 1;
}

static int luavgl_obj_is_group_def(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lua_pushboolean(L, lv_obj_is_group_def(obj));
  return 1;
}

static int luavgl_obj_is_layout_positioned(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lua_pushboolean(L, lv_obj_is_layout_positioned(obj));
  return 1;
}

static int luavgl_obj_mark_layout_as_dirty(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_obj_mark_layout_as_dirty(obj);
  return 0;
}

static int luavgl_obj_center(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_obj_center(obj);
  return 0;
}

static int luavgl_obj_invalidate(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_obj_invalidate(obj);
  return 0;
}

static int luavgl_obj_set_flex_flow(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_flex_flow_t flow = luavgl_tointeger(L, 2);

  lv_obj_set_flex_flow(obj, flow);
  return 0;
}

static int luavgl_obj_set_flex_align(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_flex_align_t m = luavgl_tointeger(L, 2);
  lv_flex_align_t c = luavgl_tointeger(L, 3);
  lv_flex_align_t t = luavgl_tointeger(L, 4);

  lv_obj_set_flex_align(obj, m, c, t);
  return 0;
}

static int luavgl_obj_set_flex_grow(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  uint8_t grow = luavgl_tointeger(L, 2);

  lv_obj_set_flex_grow(obj, grow);
  return 0;
}

static int luavgl_obj_indev_search(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_point_t point;
  if (lua_istable(L, 2)) {
    lua_geti(L, 2, 1);
    point.x = lua_tointeger(L, -1);
    lua_pop(L, 1);

    lua_geti(L, 2, 2);
    point.y = lua_tointeger(L, -1);
    lua_pop(L, 1);
  } else {
    point.x = lua_tointeger(L, 2);
    point.y = lua_tointeger(L, 3);
  }

  obj = lv_indev_search_obj(obj, &point);
  if (obj == NULL) {
    lua_pushnil(L);
  } else {
    lua_pushlightuserdata(L, obj);
    lua_rawget(L, LUA_REGISTRYINDEX);
    if (lua_isnoneornil(L, -1)) {
      luavgl_add_lobj(L, obj)->lua_created = false;
    }
  }

  return 1;
}

static int luavgl_obj_get_coords(lua_State *L) {
  lv_area_t area;
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_obj_get_coords(obj, &area);
  lua_newtable(L);

  lua_pushinteger(L, area.x1);
  lua_setfield(L, -2, "x1");

  lua_pushinteger(L, area.x2);
  lua_setfield(L, -2, "x2");

  lua_pushinteger(L, area.y1);
  lua_setfield(L, -2, "y1");

  lua_pushinteger(L, area.y2);
  lua_setfield(L, -2, "y2");

  return 1;
}

/**
 * get object real position using lv_obj_get_x/x2/y/y2
 */
static int luavgl_obj_get_pos(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lua_newtable(L);

  lua_pushinteger(L, lv_obj_get_x(obj));
  lua_setfield(L, -2, "x1");

  lua_pushinteger(L, lv_obj_get_x2(obj));
  lua_setfield(L, -2, "x2");

  lua_pushinteger(L, lv_obj_get_y(obj));
  lua_setfield(L, -2, "y1");

  lua_pushinteger(L, lv_obj_get_y2(obj));
  lua_setfield(L, -2, "y2");

  return 1;
}

/**
 * set this object as the current selection
 */
static int luavgl_obj_focus(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);

  lv_group_t *group = lv_obj_get_group(obj);
  if (group == NULL) {
    return 0;
  }
  lv_group_focus_obj(obj);

  return 0;
}

static int luavgl_obj_move_to_index(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  int idx = luavgl_tointeger(L, 2);

  lv_obj_move_to_index(obj, idx);
  return 0;
}

/**
 * Remove all animations associates to this object
 */
static int luavgl_obj_remove_anim_all(lua_State *L) {
  lv_obj_t *obj = luavgl_to_obj(L, 1);
  lv_anim_del(obj, NULL);
  return 1;
}

static int luavgl_obj_gc(lua_State *L) {
  if (lua_type(L, 1) != LUA_TUSERDATA) {
    /* If t = setmetatable({}, obj_meta_table), this will happen when t is
     * gc;ed. Currently all metatables for classes based on obj, that has no own
     * __gc will goes here.
     */
    return 0;
  }

  debug("\n");

  luavgl_obj_t *lobj = lua_touserdata(L, 1);
  if (lobj == NULL || lobj->obj == NULL) {
    /* obj is already deleted. It's ok. */
    return 0;
  }

  debug("GC for obj: %p\n", lobj->obj);
  luavgl_obj_delete(L);

  return 0;
}

static const luaL_Reg luavgl_obj_methods[] = {
    {"set", luavgl_obj_set},
    {"set_style", luavgl_obj_set_style},
    {"align_to", luavgl_obj_align_to},
    {"delete", luavgl_obj_delete},
    {"clean", luavgl_obj_clean},

    /* misc. functions */
    {"parent", luavgl_obj_set_get_parent},
    {"set_parent", luavgl_obj_set_parent},
    {"get_parent", luavgl_obj_get_parent},
    {"get_child", luavgl_obj_get_child},
    {"get_child_cnt", luavgl_obj_get_child_cnt},
    {"get_screen", luavgl_obj_get_screen},
    {"get_state", luavgl_obj_get_state},
    {"scroll_to", luavgl_obj_scroll_to},
    {"is_scrolling", luavgl_obj_is_scrolling},
    {"is_visible", luavgl_obj_is_visible},
    {"add_flag", luavgl_obj_add_flag},
    {"clear_flag", luavgl_obj_clear_flag},
    {"add_state", luavgl_obj_add_state},
    {"clear_state", luavgl_obj_clear_state},
    {"add_style", luavgl_obj_add_style},
    {"remove_style", luavgl_obj_remove_style},
    {"remove_style_all", luavgl_obj_remove_style_all},
    {"scroll_by", luavgl_obj_scroll_by},
    {"scroll_by_bounded", luavgl_obj_scroll_by_bounded},
    {"scroll_to_view", luavgl_obj_scroll_to_view},
    {"scroll_to_view_recursive", luavgl_obj_scroll_to_view_recursive},
    {"scroll_by_raw", luavgl_obj_scroll_by_raw},
    {"scrollbar_invalidate", luavgl_obj_scrollbar_invalidate},
    {"readjust_scroll", luavgl_obj_readjust_scroll},
    {"is_editable", luavgl_obj_is_editable},
    {"is_group_def", luavgl_obj_is_group_def},
    {"is_layout_positioned", luavgl_obj_is_layout_positioned},
    {"mark_layout_as_dirty", luavgl_obj_mark_layout_as_dirty},
    {"center", luavgl_obj_center},
    {"invalidate", luavgl_obj_invalidate},
    {"set_flex_flow", luavgl_obj_set_flex_flow},
    {"set_flex_align", luavgl_obj_set_flex_align},
    {"set_flex_grow", luavgl_obj_set_flex_grow},
    {"indev_search", luavgl_obj_indev_search},
    {"get_coords", luavgl_obj_get_coords},
    {"get_pos", luavgl_obj_get_pos},
    {"focus", luavgl_obj_focus},
    {"move_to_index", luavgl_obj_move_to_index},

    {"onevent", luavgl_obj_on_event},
    {"onPressed", luavgl_obj_on_pressed},
    {"onClicked", luavgl_obj_on_clicked},
    {"onShortClicked", luavgl_obj_on_short_clicked},
    {"anim", luavgl_anim_create},
    {"Anim", luavgl_anim_create},
    {"remove_all_anim", luavgl_obj_remove_anim_all}, /* remove all */
    {NULL, NULL},
};

static void luavgl_obj_init(lua_State *L) {
  /* base lv_obj */
  luavgl_obj_newmetatable(L, &lv_obj_class, "lv_obj", luavgl_obj_methods);
  lua_pushcfunction(L, luavgl_obj_gc);
  lua_setfield(L, -2, "__gc");

  /**
   * Widget creation functions is a metatable, so we can add extended widget to
   * it.
   *
   * widgets = {}
   * lib = {widget_create_methods}
   * widgets.__index = lib
   * obj.__metatable = widgets
   */
  lua_getfield(L, -1, "__index");
  luaL_newmetatable(L, "widgets");
  luaL_newlib(L, widget_create_methods);
  lua_setfield(L, -2, "__index");
  lua_setmetatable(L, -2);
  lua_pop(L, 1); /* remove obj.__index table */

  lua_pop(L, 1); /* remove obj metatable */
}

static const luavgl_value_setter_t obj_property_table[] = {
    {"x", 0, {.setter = (setter_int_t)lv_obj_set_x}},
    {"y", 0, {.setter = (setter_int_t)lv_obj_set_y}},
    {"w", 0, {.setter = (setter_int_t)lv_obj_set_width}},
    {"h", 0, {.setter = (setter_int_t)lv_obj_set_height}},
    {"align", SETTER_TYPE_STACK, {.setter_stack = _lv_obj_set_align}},

    {"scrollbar_mode", 0, {.setter = (setter_int_t)lv_obj_set_scrollbar_mode}},
    {"scroll_dir", 0, {.setter = (setter_int_t)lv_obj_set_scroll_dir}},
    {"scroll_snap_x", 0, {.setter = (setter_int_t)lv_obj_set_scroll_snap_x}},
    {"scroll_snap_y", 0, {.setter = (setter_int_t)lv_obj_set_scroll_snap_y}},
};

/**
 * Set object property.
 * Differ from set object style, this one is usually used to set widget
 * property like lv_WIDGETNAME_set_src()
 *
 * Used internally.
 *
 * Expected stack:
 * stack[-2]: key(property name)
 * stack[-1]: value(could be any lua data)
 */
LUALIB_API int luavgl_obj_set_property_kv(lua_State *L, void *data) {
  lv_obj_t *obj = data;
  int ret = luavgl_set_property(L, obj, obj_property_table);

  if (ret == 0)
    return 0;

  /* fallback to set obj local style, with default state. */
  return luavgl_obj_set_style_kv(L, obj, 0);
}

LUALIB_API int luavgl_obj_create_helper(lua_State *L,
                                        lv_obj_t *(*create)(lv_obj_t *parent)) {
  luavgl_ctx_t *ctx = luavgl_context(L);
  lv_obj_t *parent;

  if (lua_isnoneornil(L, 1)) {
    parent = ctx->root;
  } else {
    parent = luavgl_to_obj(L, 1);
    /* remove parent, in order to keep clean stack to call obj.set */
    lua_remove(L, 1);
  }

  debug("create obj on: %p\n", parent);

  lv_obj_t *obj = create(parent);
  luavgl_add_lobj(L, obj)->lua_created = true;

  if (!lua_istable(L, -2)) {
    /* no need to call setup */
    return 1;
  }

  lua_insert(L, -2); /* obj, prop */

  /* now call obj.set to setup property */
  lua_getfield(L, -2, "set"); /* obj, prop, set */
  if (!luavgl_is_callable(L, -1)) {
    /* set method not found, call basic obj set method. */
    lua_pop(L, 2); /* remove prop table, and set method */
    luavgl_setup_obj(L, obj);
  } else {
    lua_insert(L, -3); /* set, obj, prop */
    lua_call(L, 2, 0); /* now stack is clean */
    lua_pushlightuserdata(L, obj);
    lua_rawget(L, LUA_REGISTRYINDEX);
  }

  debug("create obj: %p\n", obj);
  return 1;
}

/**
 * Add existing lvgl obj to lua, return lobj(luavgl obj).
 * If no metatable not found for this obj class, then lv_obj_class metatable is
 * used
 */
LUALIB_API luavgl_obj_t *luavgl_add_lobj(lua_State *L, lv_obj_t *obj) {
  luavgl_obj_t *lobj;

  /* In rare case, obj may be deleted but not gc'ed in lua, and lvgl quickly
   * creates another obj but happen to malloced same address, thus using obj
   * light userdata as key may have some potential issues. */
  lua_pushlightuserdata(L, obj);
  lua_rawget(L, LUA_REGISTRYINDEX);
  if (!lua_isnoneornil(L, -1)) {
    /* already exists */
    return luavgl_to_lobj(L, -1);
  }
  lua_pop(L, 1); /* pop nil value */

  lobj = lua_newuserdata(L, sizeof(*lobj));

  if (luavgl_obj_getmetatable(L, obj->class_p) == LUA_TNIL) {
    lua_pop(L, 1);
    debug("cannot find metatable for class: %p\n", obj->class_p);
    /* use base obj metatable instead */
    luavgl_obj_getmetatable(L, &lv_obj_class);
  }

  lua_setmetatable(L, -2);

  memset(lobj, 0, sizeof(*lobj));
  luavgl_obj_event_init(lobj);
  lobj->obj = obj;
  lv_obj_add_event_cb(obj, obj_delete_cb, LV_EVENT_DELETE, L);

  /* registry[obj] = lobj */
  lua_pushlightuserdata(L, obj);
  lua_pushvalue(L, -2);
  lua_rawset(L, LUA_REGISTRYINDEX);
  return lobj;
}