lvgl/src/lv_objx/lv_ddlist.c

/**
 * @file lv_ddlist.c
 *
 */

/*********************
 *      INCLUDES
 *********************/
#include "lv_ddlist.h"
#if LV_USE_DDLIST != 0

#include "../lv_core/lv_debug.h"
#include "../lv_draw/lv_draw.h"
#include "../lv_core/lv_group.h"
#include "../lv_core/lv_indev.h"
#include "../lv_themes/lv_theme.h"
#include "../lv_font/lv_symbol_def.h"
#include "../lv_misc/lv_anim.h"
#include "../lv_misc/lv_math.h"
#include <string.h>

/*********************
 *      DEFINES
 *********************/
#define LV_OBJX_NAME "lv_ddlist"

#if LV_USE_ANIMATION == 0
#undef LV_DDLIST_DEF_ANIM_TIME
#define LV_DDLIST_DEF_ANIM_TIME 0 /*No animation*/
#endif

/**********************
 *      TYPEDEFS
 **********************/

/**********************
 *  STATIC PROTOTYPES
 **********************/
static lv_design_res_t lv_ddlist_design(lv_obj_t * ddlist, const lv_area_t * clip_area, lv_design_mode_t mode);
static lv_res_t lv_ddlist_signal(lv_obj_t * ddlist, lv_signal_t sign, void * param);
static lv_res_t lv_ddlist_scrl_signal(lv_obj_t * scrl, lv_signal_t sign, void * param);
static lv_style_dsc_t * lv_ddlist_get_style(lv_obj_t * ddlist, uint8_t part);
static lv_res_t release_handler(lv_obj_t * ddlist);
static void lv_ddlist_refr_size(lv_obj_t * ddlist, lv_anim_enable_t anim);
static void lv_ddlist_pos_current_option(lv_obj_t * ddlist);
static void lv_ddlist_refr_width(lv_obj_t * ddlist);
#if LV_USE_ANIMATION
static void lv_ddlist_anim_ready_cb(lv_anim_t * a);
static void lv_ddlist_anim_finish(lv_obj_t * ddlist);
static void lv_ddlist_adjust_height(lv_obj_t * ddlist, lv_anim_value_t height);
#endif

/**********************
 *  STATIC VARIABLES
 **********************/
static lv_signal_cb_t ancestor_signal;
static lv_signal_cb_t ancestor_scrl_signal;
static lv_design_cb_t ancestor_design;

/**********************
 *      MACROS
 **********************/

/**********************
 *   GLOBAL FUNCTIONS
 **********************/

/**
 * Create a drop down list objects
 * @param par pointer to an object, it will be the parent of the new drop down list
 * @param copy pointer to a drop down list object, if not NULL then the new object will be copied
 * from it
 * @return pointer to the created drop down list
 */
lv_obj_t * lv_ddlist_create(lv_obj_t * par, const lv_obj_t * copy)
{
    LV_LOG_TRACE("drop down list create started");

    /*Create the ancestor drop down list*/
    lv_obj_t * new_ddlist = lv_page_create(par, copy);
    LV_ASSERT_MEM(new_ddlist);
    if(new_ddlist == NULL) return NULL;

    if(ancestor_signal == NULL) ancestor_signal = lv_obj_get_signal_cb(new_ddlist);
    if(ancestor_scrl_signal == NULL) ancestor_scrl_signal = lv_obj_get_signal_cb(lv_page_get_scrl(new_ddlist));
    if(ancestor_design == NULL) ancestor_design = lv_obj_get_design_cb(new_ddlist);

    /*Allocate the drop down list type specific extended data*/
    lv_ddlist_ext_t * ext = lv_obj_allocate_ext_attr(new_ddlist, sizeof(lv_ddlist_ext_t));
    LV_ASSERT_MEM(ext);
    if(ext == NULL) {
        lv_obj_del(new_ddlist);
        return NULL;
    }

    /*Initialize the allocated 'ext' */
    ext->label          = NULL;
    ext->symbol         = NULL;
    ext->opened         = 0;
    ext->fix_height     = 0;
    ext->sel_opt_id     = 0;
    ext->sel_opt_id_ori = 0;
    ext->option_cnt     = 0;
    ext->stay_open      = 0;
    lv_style_dsc_init(&ext->style_sel);

    /*The signal and design functions are not copied so set them here*/
    lv_obj_set_signal_cb(new_ddlist, lv_ddlist_signal);
    lv_obj_set_signal_cb(lv_page_get_scrl(new_ddlist), lv_ddlist_scrl_signal);
    lv_obj_set_design_cb(new_ddlist, lv_ddlist_design);

    /*Init the new drop down list drop down list*/
    if(copy == NULL) {
        lv_page_set_anim_time(new_ddlist, LV_DDLIST_DEF_ANIM_TIME);

        lv_obj_t * scrl = lv_page_get_scrl(new_ddlist);
        lv_obj_set_drag(scrl, false);
        lv_page_set_scrl_fit2(new_ddlist, LV_FIT_FILL, LV_FIT_TIGHT);

        /*Save (a later restore) the original X coordinate because it changes as the FITs applies*/
        lv_coord_t x;
        if(lv_obj_get_base_dir(new_ddlist) == LV_BIDI_DIR_RTL) x = lv_obj_get_x(new_ddlist) + lv_obj_get_width(new_ddlist);
        else x = lv_obj_get_x(new_ddlist);

        ext->label = lv_label_create(new_ddlist, NULL);
        lv_cont_set_fit2(new_ddlist, LV_FIT_TIGHT, LV_FIT_NONE);
        lv_page_set_sb_mode(new_ddlist, LV_SB_MODE_HIDE);

        lv_ddlist_set_options(new_ddlist, "Option 1\nOption 2\nOption 3");

        lv_obj_reset_style(new_ddlist, LV_DDLIST_PART_SCRL);
        _ot(new_ddlist, LV_DDLIST_PART_SCRL, DDLIST_SCRL);
        _ot(new_ddlist, LV_DDLIST_PART_SEL, DDLIST_SEL);


        /*Restore the original X coordinate*/
        if(lv_obj_get_base_dir(new_ddlist) == LV_BIDI_DIR_RTL) lv_obj_set_x(new_ddlist, x - lv_obj_get_width(new_ddlist));
        else lv_obj_set_x(new_ddlist, x);
    }
    /*Copy an existing drop down list*/
    else {
        lv_ddlist_ext_t * copy_ext = lv_obj_get_ext_attr(copy);
        ext->label                 = lv_label_create(new_ddlist, copy_ext->label);
        lv_label_set_text(ext->label, lv_label_get_text(copy_ext->label));
        ext->sel_opt_id     = copy_ext->sel_opt_id;
        ext->sel_opt_id_ori = copy_ext->sel_opt_id;
        ext->fix_height     = copy_ext->fix_height;
        ext->option_cnt     = copy_ext->option_cnt;
        ext->symbol           = copy_ext->symbol;
        ext->stay_open      = copy_ext->stay_open;
    }

    LV_LOG_INFO("drop down list created");

    return new_ddlist;
}

/*=====================
 * Setter functions
 *====================*/

/**
 * Set the options in a drop down list from a string
 * @param ddlist pointer to drop down list object
 * @param options a string with '\n' separated options. E.g. "One\nTwo\nThree"
 */
void lv_ddlist_set_options(lv_obj_t * ddlist, const char * options)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);
    LV_ASSERT_STR(options);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    /*Count the '\n'-s to determine the number of options*/
    ext->option_cnt = 0;
    uint16_t i;
    for(i = 0; options[i] != '\0'; i++) {
        if(options[i] == '\n') ext->option_cnt++;
    }
    ext->option_cnt++; /*Last option has no `\n`*/
    ext->sel_opt_id     = 0;
    ext->sel_opt_id_ori = 0;

    lv_label_set_text(ext->label, options);

    lv_ddlist_refr_width(ddlist);

    lv_label_align_t align = lv_label_get_align(ext->label);
    switch(align) {
        case LV_LABEL_ALIGN_LEFT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_LEFT_MID, 0, 0); break;
        case LV_LABEL_ALIGN_CENTER: lv_obj_align(ext->label, NULL, LV_ALIGN_CENTER, 0, 0); break;
        case LV_LABEL_ALIGN_RIGHT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_RIGHT_MID, 0, 0); break;
    }

    lv_ddlist_refr_size(ddlist, false);
}

/**
 * Set the selected option
 * @param ddlist pointer to drop down list object
 * @param sel_opt id of the selected option (0 ... number of option - 1);
 */
void lv_ddlist_set_selected(lv_obj_t * ddlist, uint16_t sel_opt)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
    if(ext->sel_opt_id == sel_opt) return;

    ext->sel_opt_id     = sel_opt < ext->option_cnt ? sel_opt : ext->option_cnt - 1;
    ext->sel_opt_id_ori = ext->sel_opt_id;
    /*Move the list to show the current option*/
    if(ext->opened == 0) {
        lv_ddlist_pos_current_option(ddlist);
    } else {
        lv_obj_invalidate(ddlist);
    }
}

/**
 * Set a fix height for the drop down list
 * If 0 then the opened ddlist will be auto. sized else the set height will be applied.
 * @param ddlist pointer to a drop down list
 * @param h the height when the list is opened (0: auto size)
 */
void lv_ddlist_set_fix_height(lv_obj_t * ddlist, lv_coord_t h)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
    if(ext->fix_height == h) return;

    ext->fix_height = h;

    lv_ddlist_refr_size(ddlist, false);
}

/**
 * Set a fix width for the drop down list
 * @param ddlist pointer to a drop down list
 * @param w the width when the list is opened (0: auto size)
 */
void lv_ddlist_set_fix_width(lv_obj_t * ddlist, lv_coord_t w)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
    if(w == 0) {
        lv_cont_set_fit2(ddlist, LV_FIT_TIGHT, lv_cont_get_fit_bottom(ddlist));
    } else {
        lv_cont_set_fit2(ddlist, LV_FIT_NONE, lv_cont_get_fit_bottom(ddlist));
        lv_obj_set_width(ddlist, w);
    }

    switch(lv_label_get_align(ext->label)) {
        case LV_LABEL_ALIGN_LEFT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_LEFT_MID, 0, 0); break;
        case LV_LABEL_ALIGN_CENTER: lv_obj_align(ext->label, NULL, LV_ALIGN_CENTER, 0, 0); break;
        case LV_LABEL_ALIGN_RIGHT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_RIGHT_MID, 0, 0); break;
    }

    lv_ddlist_refr_size(ddlist, false);
}

/**
 * Set an arrow or other symbol to display when the drop-down list is closed.
 * @param ddlist pointer to drop down list object
 * @param symbol a text like `LV_SYMBOL_DOWN` or NULL to not draw icon
 */
void lv_ddlist_set_symbol(lv_obj_t * ddlist, const char * symbol)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
    ext->symbol = symbol;
    lv_obj_invalidate(ddlist);
}

/**
 * Leave the list opened when a new value is selected
 * @param ddlist pointer to drop down list object
 * @param en enable/disable "stay open" feature
 */
void lv_ddlist_set_stay_open(lv_obj_t * ddlist, bool en)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    /*Set the flag*/
    ext->stay_open = en ? 1 : 0;
}

void lv_ddlist_set_align(lv_obj_t * ddlist, lv_label_align_t align)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    lv_label_set_align(ext->label, align);
    switch(align) {
        case LV_LABEL_ALIGN_LEFT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_LEFT_MID, 0, 0); break;
        case LV_LABEL_ALIGN_CENTER: lv_obj_align(ext->label, NULL, LV_ALIGN_CENTER, 0, 0); break;
        case LV_LABEL_ALIGN_RIGHT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_RIGHT_MID, 0, 0); break;
    }
}
/*=====================
 * Getter functions
 *====================*/

/**
 * Get the options of a drop down list
 * @param ddlist pointer to drop down list object
 * @return the options separated by '\n'-s (E.g. "Option1\nOption2\nOption3")
 */
const char * lv_ddlist_get_options(const lv_obj_t * ddlist)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
    return lv_label_get_text(ext->label);
}

/**
 * Get the selected option
 * @param ddlist pointer to drop down list object
 * @return id of the selected option (0 ... number of option - 1);
 */
uint16_t lv_ddlist_get_selected(const lv_obj_t * ddlist)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    return ext->sel_opt_id;
}

/**
 * Get the total number of options
 * @param ddlist pointer to drop down list object
 * @return the total number of options in the list
 */
uint16_t lv_ddlist_get_option_cnt(const lv_obj_t * ddlist)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    return ext->option_cnt;
}

/**
 * Get the current selected option as a string
 * @param ddlist pointer to ddlist object
 * @param buf pointer to an array to store the string
 * @param buf_size size of `buf` in bytes. 0: to ignore it.
 */
void lv_ddlist_get_selected_str(const lv_obj_t * ddlist, char * buf, uint16_t buf_size)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    uint16_t i;
    uint16_t line        = 0;
    const char * opt_txt = lv_label_get_text(ext->label);
    size_t txt_len     = strlen(opt_txt);

    for(i = 0; i < txt_len && line != ext->sel_opt_id; i++) {
        if(opt_txt[i] == '\n') line++;
    }

    uint16_t c;
    for(c = 0; opt_txt[i] != '\n' && i < txt_len; c++, i++) {
        if(buf_size && c >= buf_size - 1) {
            LV_LOG_WARN("lv_ddlist_get_selected_str: the buffer was too small")
            break;
        }
        buf[c] = opt_txt[i];
    }

    buf[c] = '\0';
}

/**
 * Get the fix height value.
 * @param ddlist pointer to a drop down list object
 * @return the height if the ddlist is opened (0: auto size)
 */
lv_coord_t lv_ddlist_get_fix_height(const lv_obj_t * ddlist)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
    return ext->fix_height;
}

/**
 * Get the symbol to draw when the drop-down list is closed
 * @param ddlist pointer to drop down list object
 * @return the symbol or NULL if not enabled
 */
const char * lv_ddlist_get_symbol(lv_obj_t * ddlist)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    return ext->symbol;
}

/**
 * Get whether the drop down list stay open after selecting a  value or not
 * @param ddlist pointer to drop down list object
 */
bool lv_ddlist_get_stay_open(lv_obj_t * ddlist)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    return ext->stay_open ? true : false;
}

/**
 * Get the alignment of the labels in a drop down list
 * @param ddlist pointer to a drop down list object
 * @return alignment of labels
 */
lv_label_align_t lv_ddlist_get_align(const lv_obj_t * ddlist)
{
    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    return lv_label_get_align(ext->label);
}

/*=====================
 * Other functions
 *====================*/

/**
 * Open the drop down list with or without animation
 * @param ddlist pointer to drop down list object
 * @param anim_en LV_ANIM_EN: use animation; LV_ANIM_OFF: not use animations
 */
void lv_ddlist_open(lv_obj_t * ddlist, lv_anim_enable_t anim)
{
#if LV_USE_ANIMATION == 0
    anim = false;
#endif
    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
    ext->opened           = 1;
    lv_obj_set_drag(lv_page_get_scrl(ddlist), true);
    lv_ddlist_refr_size(ddlist, anim);
}

/**
 * Close (Collapse) the drop down list
 * @param ddlist pointer to drop down list object
 * @param anim_en LV_ANIM_ON: use animation; LV_ANIM_OFF: not use animations
 */
void lv_ddlist_close(lv_obj_t * ddlist, lv_anim_enable_t anim)
{
#if LV_USE_ANIMATION == 0
    anim = false;
#endif
    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
    ext->opened           = 0;
    lv_obj_set_drag(lv_page_get_scrl(ddlist), false);
    lv_ddlist_refr_size(ddlist, anim);
}

/**********************
 *   STATIC FUNCTIONS
 **********************/

/**
 * Handle the drawing related tasks of the drop down lists
 * @param ddlist pointer to an object
 * @param clip_area the object will be drawn only in this area
 * @param mode LV_DESIGN_COVER_CHK: only check if the object fully covers the 'mask_p' area
 *                                  (return 'true' if yes)
 *             LV_DESIGN_DRAW: draw the object (always return 'true')
 *             LV_DESIGN_DRAW_POST: drawing after every children are drawn
 * @param return an element of `lv_design_res_t`
 */
static lv_design_res_t lv_ddlist_design(lv_obj_t * ddlist, const lv_area_t * clip_area, lv_design_mode_t mode)
{
    /*Return false if the object is not covers the mask_p area*/
    if(mode == LV_DESIGN_COVER_CHK) {
        return ancestor_design(ddlist, clip_area, mode);
    }
    /*Draw the object*/
    else if(mode == LV_DESIGN_DRAW_MAIN) {
        ancestor_design(ddlist, clip_area, mode);

        lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
        /*If the list is opened draw a rectangle under the selected item*/
        if(ext->opened != 0 || ext->force_sel) {
            const lv_font_t * font   = lv_obj_get_style_ptr(ddlist, LV_DDLIST_PART_BG, LV_STYLE_FONT);
            lv_style_int_t line_space   = lv_obj_get_style_int(ddlist, LV_DDLIST_PART_BG, LV_STYLE_LINE_SPACE);
            lv_coord_t font_h        = lv_font_get_line_height(font);

            /*Draw the selected*/
            lv_area_t rect_area;
            rect_area.y1 = ext->label->coords.y1;
            rect_area.y1 += ext->sel_opt_id * (font_h + line_space);
            rect_area.y1 -= line_space / 2;

            rect_area.y2 = rect_area.y1 + font_h + line_space - 1;
            rect_area.x1 = ddlist->coords.x1;
            rect_area.x2 = ddlist->coords.x2;

            lv_draw_rect_dsc_t sel_rect;
            lv_draw_rect_dsc_init(&sel_rect);
            lv_obj_init_draw_rect_dsc(ddlist, LV_DDLIST_PART_SEL, &sel_rect);
            lv_draw_rect(&rect_area, clip_area, &sel_rect);
        }
    }
    /*Post draw when the children are drawn*/
    else if(mode == LV_DESIGN_DRAW_POST) {
        /*Redraw the text on the selected area with a different color*/
        lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

        /*Redraw only in opened state*/
        if(ext->opened || ext->force_sel) {
            lv_draw_label_dsc_t label_dsc;
            lv_draw_label_dsc_init(&label_dsc);
            lv_obj_init_draw_label_dsc(ddlist, LV_DDLIST_PART_SEL, &label_dsc);
            lv_coord_t font_h        = lv_font_get_line_height(label_dsc.font);

            lv_area_t area_sel;
            area_sel.y1 = ext->label->coords.y1;
            area_sel.y1 += ext->sel_opt_id * (font_h + label_dsc.line_space);
            area_sel.y1 -= label_dsc.line_space / 2;

            area_sel.y2 = area_sel.y1 + font_h + label_dsc.line_space - 1;
            area_sel.x1 = ddlist->coords.x1;
            area_sel.x2 = ddlist->coords.x2;
            lv_area_t mask_sel;
            bool area_ok;
            area_ok = lv_area_intersect(&mask_sel, clip_area, &area_sel);
            if(area_ok) {
                lv_draw_label(&ext->label->coords, &mask_sel, &label_dsc, lv_label_get_text(ext->label), NULL);
            }
        }

        /*Closed...*/
        else {
            /*Draw the symbol if enabled*/
            if(ext->symbol) {
                lv_draw_label_dsc_t label_dsc;
                lv_draw_label_dsc_init(&label_dsc);
                lv_obj_init_draw_label_dsc(ddlist, LV_DDLIST_PART_BG, &label_dsc);
                lv_coord_t font_h            = lv_font_get_line_height(label_dsc.font);
                lv_area_t area_icon;
                lv_coord_t icon_width = lv_txt_get_width(ext->symbol, (uint16_t)strlen(ext->symbol), label_dsc.font, 0, 0);


                if(lv_label_get_align(ext->label) != LV_LABEL_ALIGN_RIGHT) {
                    area_icon.x2 = ddlist->coords.x2 - lv_obj_get_style_int(ddlist, LV_DDLIST_PART_BG, LV_STYLE_PAD_RIGHT);
                    area_icon.x1 = area_icon.x2 - icon_width;
                } else {
                    area_icon.x1 = ddlist->coords.x1 + lv_obj_get_style_int(ddlist, LV_DDLIST_PART_BG, LV_STYLE_PAD_LEFT);
                    area_icon.x2 = area_icon.x1 + icon_width;
                }

                area_icon.y1 = ddlist->coords.y1 + label_dsc.line_space;
                area_icon.y2 = area_icon.y1 + font_h;

                lv_area_t mask_icon;
                bool area_ok;
                area_ok = lv_area_intersect(&mask_icon, clip_area, &area_icon);
                if(area_ok) {
                    lv_draw_label(&area_icon, &mask_icon, &label_dsc, ext->symbol, NULL);
                }
            }
        }
        /*Draw the scrollbar in the ancestor page design function*/
        ancestor_design(ddlist, clip_area, mode);
    }

    return LV_DESIGN_RES_OK;
}

/**
 * Signal function of the drop down list
 * @param ddlist pointer to a drop down list object
 * @param sign a signal type from lv_signal_t enum
 * @param param pointer to a signal specific variable
 * @return LV_RES_OK: the object is not deleted in the function; LV_RES_INV: the object is deleted
 */
static lv_res_t lv_ddlist_signal(lv_obj_t * ddlist, lv_signal_t sign, void * param)
{
    lv_res_t res;
    if(sign == LV_SIGNAL_GET_STYLE) {
        uint8_t ** type_p = param;
        lv_style_dsc_t ** style_dsc_p = param;
        *style_dsc_p = lv_ddlist_get_style(ddlist, **type_p);
        return LV_RES_OK;
    }

    /* Include the ancient signal function */
    res = ancestor_signal(ddlist, sign, param);
    if(res != LV_RES_OK) return res;
    if(sign == LV_SIGNAL_GET_TYPE) return lv_obj_handle_get_type_signal(param, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    if(sign == LV_SIGNAL_STYLE_CHG) {
        lv_ddlist_refr_width(ddlist);
        lv_ddlist_refr_size(ddlist, 0);
    } else if(sign == LV_SIGNAL_BASE_DIR_CHG) {
        lv_label_align_t align = lv_label_get_align(ext->label);
        switch(align) {
            case LV_LABEL_ALIGN_LEFT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_LEFT_MID, 0, 0); break;
            case LV_LABEL_ALIGN_CENTER: lv_obj_align(ext->label, NULL, LV_ALIGN_CENTER, 0, 0); break;
            case LV_LABEL_ALIGN_RIGHT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_RIGHT_MID, 0, 0); break;
        }

        lv_ddlist_refr_size(ddlist, 0);
    } else if(sign == LV_SIGNAL_CLEANUP) {
        ext->label = NULL;
    } else if(sign == LV_SIGNAL_FOCUS) {
#if LV_USE_GROUP
        lv_group_t * g             = lv_obj_get_group(ddlist);
        bool editing               = lv_group_get_editing(g);
        lv_indev_type_t indev_type = lv_indev_get_type(lv_indev_get_act());

        /*Encoders need special handling*/
        if(indev_type == LV_INDEV_TYPE_ENCODER) {
            /*Open the list if editing*/
            if(editing) {
                ext->opened         = true;
                ext->sel_opt_id_ori = ext->sel_opt_id;
                lv_ddlist_refr_size(ddlist, true);
            }
            /*Close the lift if navigating*/
            else {
                ext->opened     = false;
                ext->sel_opt_id = ext->sel_opt_id_ori;
                lv_ddlist_refr_size(ddlist, true);
            }
        } else {
            /*Open the list if closed*/
            if(!ext->opened) {
                ext->opened         = true;
                ext->sel_opt_id_ori = ext->sel_opt_id; /*Save the current value. Used to revert this
                                                          state if ENER wont't be pressed*/
                lv_ddlist_refr_size(ddlist, true);
            }
        }
#endif
    } else if(sign == LV_SIGNAL_RELEASED) {
        release_handler(ddlist);
    } else if(sign == LV_SIGNAL_DEFOCUS) {
        if(ext->opened) {
            ext->opened     = false;
            ext->sel_opt_id = ext->sel_opt_id_ori;
            lv_ddlist_refr_size(ddlist, true);
        }
    } else if(sign == LV_SIGNAL_CONTROL) {
        char c = *((char *)param);
        if(c == LV_KEY_RIGHT || c == LV_KEY_DOWN) {
            if(!ext->opened) {
                ext->opened = 1;
                lv_ddlist_refr_size(ddlist, true);
            }

            if(ext->sel_opt_id + 1 < ext->option_cnt) {
                ext->sel_opt_id++;
                lv_ddlist_pos_current_option(ddlist);
                lv_obj_invalidate(ddlist);
            }
        } else if(c == LV_KEY_LEFT || c == LV_KEY_UP) {
            if(!ext->opened) {
                ext->opened = 1;
                lv_ddlist_refr_size(ddlist, true);
            }
            if(ext->sel_opt_id > 0) {
                ext->sel_opt_id--;
                lv_ddlist_pos_current_option(ddlist);
                lv_obj_invalidate(ddlist);
            }
        } else if(c == LV_KEY_ESC) {
            if(ext->opened) {
                ext->opened     = 0;
                ext->sel_opt_id = ext->sel_opt_id_ori;
                lv_ddlist_refr_size(ddlist, true);
            }
        }
    } else if(sign == LV_SIGNAL_GET_EDITABLE) {
        bool * editable = (bool *)param;
        *editable       = true;
    }

    return res;
}

/**
 * Signal function of the drop down list's scrollable part
 * @param scrl pointer to a drop down list's scrollable part
 * @param sign a signal type from lv_signal_t enum
 * @param param pointer to a signal specific variable
 * @return LV_RES_OK: the object is not deleted in the function; LV_RES_INV: the object is deleted
 */
static lv_res_t lv_ddlist_scrl_signal(lv_obj_t * scrl, lv_signal_t sign, void * param)
{
    lv_res_t res;

    /* Include the ancient signal function */
    res = ancestor_scrl_signal(scrl, sign, param);
    if(res != LV_RES_OK) return res;
    if(sign == LV_SIGNAL_GET_TYPE) return lv_obj_handle_get_type_signal(param, "");

    lv_obj_t * ddlist = lv_obj_get_parent(scrl);

    if(sign == LV_SIGNAL_REFR_EXT_DRAW_PAD) {
        /* Make possible to draw on the full width of the background to redraw the selected rectangle
         * when the ddlist is scrolled in fix height mode.
         * (The scrollabel is scrolled the "select rectangle" is drawn on the bg too)*/
        lv_style_int_t left = lv_obj_get_style_int(ddlist, LV_DDLIST_PART_BG, LV_STYLE_PAD_LEFT);
        lv_style_int_t right = lv_obj_get_style_int(ddlist, LV_DDLIST_PART_BG, LV_STYLE_PAD_RIGHT);
        ddlist->ext_draw_pad = LV_MATH_MAX(ddlist->ext_draw_pad, LV_MATH_MAX(left, right));
    } else if(sign == LV_SIGNAL_RELEASED) {
        if(lv_indev_is_dragging(lv_indev_get_act()) == false) {
            release_handler(ddlist);
        }
    } else if(sign == LV_SIGNAL_CLEANUP) {
        lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
        ext->label            = NULL; /*The label is already deleted*/
    }

    return res;
}

/**
 * Get the style descriptor of a part of the object
 * @param page pointer the object
 * @param part the part from `lv_ddlist_part_t`. (LV_DDLIST_PART_...)
 * @return pointer to the style descriptor of the specified part
 */
static lv_style_dsc_t * lv_ddlist_get_style(lv_obj_t * ddlist, uint8_t part)
{
    LV_ASSERT_OBJ(ddlist, LV_OBJX_NAME);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
    lv_style_dsc_t * style_dsc_p;

    switch(part) {
    case LV_DDLIST_PART_BG:
        style_dsc_p = &ddlist->style_dsc;
        break;
    case LV_DDLIST_PART_SCRL:
        style_dsc_p = lv_obj_get_style(ext->page.scrl, LV_CONT_PART_MAIN);
        break;
    case LV_DDLIST_PART_SCRLBAR:
        style_dsc_p = &ext->page.sb.style;
        break;
    case LV_DDLIST_PART_SEL:
        style_dsc_p = &ext->style_sel;
        break;
    default:
        style_dsc_p = NULL;
    }

    return style_dsc_p;
}

/**
 * Called when a drop down list is released to open it or set new option
 * @param ddlist pointer to a drop down list object
 * @return LV_ACTION_RES_INV if the ddlist it deleted in the user callback else LV_ACTION_RES_OK
 */
static lv_res_t release_handler(lv_obj_t * ddlist)
{
    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    if(ext->opened == 0) { /*Open the list*/
        ext->opened = 1;
        lv_obj_set_drag(lv_page_get_scrl(ddlist), true);
        lv_ddlist_refr_size(ddlist, true);
    } else {

        lv_indev_t * indev = lv_indev_get_act();
#if LV_USE_GROUP
        /*Leave edit mode once a new item is selected*/
        if(lv_indev_get_type(indev) == LV_INDEV_TYPE_ENCODER) {
            ext->sel_opt_id_ori = ext->sel_opt_id;
            lv_group_t * g      = lv_obj_get_group(ddlist);
            if(lv_group_get_editing(g)) {
                lv_group_set_editing(g, false);
            }
        }
#endif

        /*Search the clicked option (For KEYPAD and ENCODER the new value should be already set)*/
        if(lv_indev_get_type(indev) == LV_INDEV_TYPE_POINTER || lv_indev_get_type(indev) == LV_INDEV_TYPE_BUTTON) {
            lv_point_t p;
            lv_indev_get_point(indev, &p);
            p.y -= ext->label->coords.y1;
            p.x -= ext->label->coords.x1;
            uint16_t letter_i;
            letter_i = lv_label_get_letter_on(ext->label, &p);

            uint16_t new_opt  = 0;
            const char * txt  = lv_label_get_text(ext->label);
            uint32_t i        = 0;
            uint32_t i_prev   = 0;

            uint32_t letter_cnt = 0;
            uint32_t letter;
            for(letter_cnt = 0; letter_cnt < letter_i; letter_cnt++) {
                letter = lv_txt_encoded_next(txt, &i);
                /*Count he lines to reach the clicked letter. But ignore the last '\n' because it
                 * still belongs to the clicked line*/
                if(letter == '\n' && i_prev != letter_i) new_opt++;
                i_prev = i;
            }

            ext->sel_opt_id     = new_opt;
            ext->sel_opt_id_ori = ext->sel_opt_id;
        }

        uint32_t id  = ext->sel_opt_id; /*Just to use uint32_t in event data*/
        lv_res_t res = lv_event_send(ddlist, LV_EVENT_VALUE_CHANGED, &id);
        if(res != LV_RES_OK) return res;

        if(ext->stay_open == 0) {
            ext->opened = 0;
            lv_obj_set_drag(lv_page_get_scrl(ddlist), false);
            lv_ddlist_refr_size(ddlist, true);
        } else {
            lv_obj_invalidate(ddlist);
        }
    }

    return LV_RES_OK;
}

/**
 * Refresh the size of drop down list according to its status (open or closed)
 * @param ddlist pointer to a drop down list object
 * @param anim Change the size (open/close) with or without animation (true/false)
 */
static void lv_ddlist_refr_size(lv_obj_t * ddlist, lv_anim_enable_t anim)
{
#if LV_USE_ANIMATION == 0
    anim = false;
#endif
    lv_ddlist_ext_t * ext    = lv_obj_get_ext_attr(ddlist);
    lv_coord_t new_height;

    /*Open the list*/
    if(ext->opened) {
        if(ext->fix_height == 0) {
            lv_style_int_t top = lv_obj_get_style_int(ddlist, LV_DDLIST_PART_BG, LV_STYLE_PAD_TOP);
            lv_style_int_t bottom = lv_obj_get_style_int(ddlist, LV_DDLIST_PART_BG, LV_STYLE_PAD_BOTTOM);
            new_height = lv_obj_get_height(lv_page_get_scrl(ddlist)) + top + bottom;
        } else {
            new_height = ext->fix_height;
        }

    }
    /*Close the list*/
    else {
        const lv_font_t * font         = lv_obj_get_style_ptr(ddlist, LV_DDLIST_PART_BG, LV_STYLE_FONT);
        lv_coord_t font_h              = lv_font_get_line_height(font);
        new_height                     = font_h + 2 * lv_obj_get_style_int(ddlist, LV_DDLIST_PART_BG, LV_STYLE_LINE_SPACE);

        lv_page_set_sb_mode(ddlist, LV_SB_MODE_HIDE);
    }

    if(anim == LV_ANIM_OFF) {
        lv_obj_set_height(ddlist, new_height);
        lv_ddlist_pos_current_option(ddlist);
        if(ext->opened) lv_page_set_sb_mode(ddlist, LV_SB_MODE_UNHIDE);
#if LV_USE_ANIMATION
        lv_anim_del(ddlist, (lv_anim_exec_xcb_t)lv_ddlist_adjust_height); /*If an animation is in progress then
                                                                 it will overwrite this changes*/

        /*Force animation complete to fix highlight selection*/
        lv_ddlist_anim_finish(ddlist);
    } else {
        /*Run the animation only if the the size will be different*/
        if(lv_obj_get_height(ddlist) != new_height) {
            lv_anim_t a;
            a.var            = ddlist;
            a.start          = lv_obj_get_height(ddlist);
            a.end            = new_height;
            a.exec_cb        = (lv_anim_exec_xcb_t)lv_ddlist_adjust_height;
            a.path_cb        = lv_anim_path_linear;
            a.ready_cb       = lv_ddlist_anim_ready_cb;
            a.act_time       = 0;
            a.time           = lv_ddlist_get_anim_time(ddlist);
            a.playback       = 0;
            a.playback_pause = 0;
            a.repeat         = 0;
            a.repeat_pause   = 0;

            ext->force_sel = 1; /*Keep the list item selected*/
            lv_anim_create(&a);
        }
#endif
    }
}

#if LV_USE_ANIMATION
/**
 * Position the list and remove the selection highlight if it's closed.
 * Called at end of list animation.
 * @param a pointer to the animation
 */
static void lv_ddlist_anim_ready_cb(lv_anim_t * a)
{
    lv_obj_t * ddlist = a->var;
    lv_ddlist_anim_finish(ddlist);
}

/**
 * Clean up after the open animation
 * @param ddlist
 */
static void lv_ddlist_anim_finish(lv_obj_t * ddlist)
{
    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    lv_ddlist_pos_current_option(ddlist);
    ext->force_sel = 0; /*Turn off drawing of selection*/
    if(ext->opened) lv_page_set_sb_mode(ddlist, LV_SB_MODE_UNHIDE);
}

/**
 * Adjusts the ddlist's height and then positions the option within it's new height.
 * This keeps the option visible during animation.
 * @param ddlist Drop down list object
 * @param height New drop down list height
 */
static void lv_ddlist_adjust_height(lv_obj_t * ddlist, lv_anim_value_t height)
{
    lv_obj_set_height(ddlist, height);
    lv_ddlist_pos_current_option(ddlist);
}
#endif

/**
 * Set the position of list when it is closed to show the selected item
 * @param ddlist pointer to a drop down list
 */
static void lv_ddlist_pos_current_option(lv_obj_t * ddlist)
{
    lv_ddlist_ext_t * ext          = lv_obj_get_ext_attr(ddlist);
    const lv_font_t * font         = lv_obj_get_style_ptr(ddlist, LV_DDLIST_PART_BG, LV_STYLE_FONT);
    lv_coord_t font_h              = lv_font_get_line_height(font);
    lv_obj_t * scrl                = lv_page_get_scrl(ddlist);

    lv_coord_t h = lv_obj_get_height(ddlist);
    lv_style_int_t line_space = lv_obj_get_style_int(ddlist, LV_DDLIST_PART_BG, LV_STYLE_LINE_SPACE);
    lv_coord_t line_y1 =
        ext->sel_opt_id * (font_h + line_space) + ext->label->coords.y1 - scrl->coords.y1;

    lv_obj_set_y(scrl, -line_y1 + (h - font_h) / 2);
    lv_obj_invalidate(ddlist);
}

/**
 * Be sure the width of the scrollable exactly fits the ddlist
 * @param ddlist pointer to a ddlist
 */
static void lv_ddlist_refr_width(lv_obj_t * ddlist)
{
    /*Save the current x coordinate because it should be kept after the refrsh*/
    lv_coord_t x;
    if(lv_obj_get_base_dir(ddlist) == LV_BIDI_DIR_RTL) x = lv_obj_get_x(ddlist) + lv_obj_get_width(ddlist);
    else x = lv_obj_get_x(ddlist);

    lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);

    /*Set the TIGHT fit horizontally the set the width to the content*/
    lv_page_set_scrl_fit2(ddlist, LV_FIT_TIGHT, lv_page_get_scrl_fit_bottom(ddlist));

    /*Revert FILL fit to fill the parent with the options area. It allows to RIGHT/CENTER align the text*/
    lv_page_set_scrl_fit2(ddlist, LV_FIT_FILL, lv_page_get_scrl_fit_bottom(ddlist));

    if(lv_obj_get_base_dir(ddlist) == LV_BIDI_DIR_RTL) lv_obj_set_x(ddlist, x - lv_obj_get_width(ddlist));
    else lv_obj_set_x(ddlist, x);

    switch(lv_label_get_align(ext->label)) {
        case LV_LABEL_ALIGN_LEFT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_LEFT_MID, 0, 0); break;
        case LV_LABEL_ALIGN_CENTER: lv_obj_align(ext->label, NULL, LV_ALIGN_CENTER, 0, 0); break;
        case LV_LABEL_ALIGN_RIGHT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_RIGHT_MID, 0, 0); break;
    }
}

#endif