/**
 * @file lv_img_decoder.c
 *
 */

/*********************
 *      INCLUDES
 *********************/
#include "lv_img_decoder.h"
#include "../misc/lv_assert.h"
#include "../draw/lv_draw_img.h"
#include "../misc/lv_ll.h"
#include "../misc/lv_gc.h"

/*********************
 *      DEFINES
 *********************/
#define CF_BUILT_IN_FIRST   LV_IMG_CF_TRUE_COLOR
#define CF_BUILT_IN_LAST    LV_IMG_CF_RGB565A8

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

typedef struct {
    lv_fs_file_t f;
    lv_color_t * palette;
    lv_opa_t * opa;
} lv_img_decoder_built_in_data_t;

/**********************
 *  STATIC PROTOTYPES
 **********************/
static lv_res_t lv_img_decoder_built_in_line_true_color(lv_img_decoder_dsc_t * dsc, lv_coord_t x, lv_coord_t y,
                                                        lv_coord_t len, uint8_t * buf);
static lv_res_t lv_img_decoder_built_in_line_alpha(lv_img_decoder_dsc_t * dsc, lv_coord_t x, lv_coord_t y,
                                                   lv_coord_t len, uint8_t * buf);
static lv_res_t lv_img_decoder_built_in_line_indexed(lv_img_decoder_dsc_t * dsc, lv_coord_t x, lv_coord_t y,
                                                     lv_coord_t len, uint8_t * buf);

/**********************
 *  STATIC VARIABLES
 **********************/

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

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

/**
 * Initialize the image decoder module
 */
void _lv_img_decoder_init(void)
{
    _lv_ll_init(&LV_GC_ROOT(_lv_img_decoder_ll), sizeof(lv_img_decoder_t));

    lv_img_decoder_t * decoder;

    /*Create a decoder for the built in color format*/
    decoder = lv_img_decoder_create();
    LV_ASSERT_MALLOC(decoder);
    if(decoder == NULL) {
        LV_LOG_WARN("lv_img_decoder_init: out of memory");
        return;
    }

    lv_img_decoder_set_info_cb(decoder, lv_img_decoder_built_in_info);
    lv_img_decoder_set_open_cb(decoder, lv_img_decoder_built_in_open);
    lv_img_decoder_set_read_line_cb(decoder, lv_img_decoder_built_in_read_line);
    lv_img_decoder_set_close_cb(decoder, lv_img_decoder_built_in_close);
}

/**
 * Get information about an image.
 * Try the created image decoder one by one. Once one is able to get info that info will be used.
 * @param src the image source. E.g. file name or variable.
 * @param header the image info will be stored here
 * @return LV_RES_OK: success; LV_RES_INV: wasn't able to get info about the image
 */
lv_res_t lv_img_decoder_get_info(const void * src, lv_img_header_t * header)
{
    lv_memset_00(header, sizeof(lv_img_header_t));

    if(src == NULL) return LV_RES_INV;

    lv_img_src_t src_type = lv_img_src_get_type(src);
    if(src_type == LV_IMG_SRC_VARIABLE) {
        const lv_img_dsc_t * img_dsc = src;
        if(img_dsc->data == NULL) return LV_RES_INV;
    }

    lv_res_t res = LV_RES_INV;
    lv_img_decoder_t * d;
    _LV_LL_READ(&LV_GC_ROOT(_lv_img_decoder_ll), d) {
        if(d->info_cb) {
            res = d->info_cb(d, src, header);
            if(res == LV_RES_OK) break;
        }
    }

    return res;
}

lv_res_t lv_img_decoder_open(lv_img_decoder_dsc_t * dsc, const void * src, lv_color_t color, int32_t frame_id)
{
    lv_memset_00(dsc, sizeof(lv_img_decoder_dsc_t));

    if(src == NULL) return LV_RES_INV;
    lv_img_src_t src_type = lv_img_src_get_type(src);
    if(src_type == LV_IMG_SRC_VARIABLE) {
        const lv_img_dsc_t * img_dsc = src;
        if(img_dsc->data == NULL) return LV_RES_INV;
    }

    dsc->color    = color;
    dsc->src_type = src_type;
    dsc->frame_id = frame_id;

    if(dsc->src_type == LV_IMG_SRC_FILE) {
        size_t fnlen = strlen(src);
        dsc->src = lv_mem_alloc(fnlen + 1);
        LV_ASSERT_MALLOC(dsc->src);
        if(dsc->src == NULL) {
            LV_LOG_WARN("lv_img_decoder_open: out of memory");
            return LV_RES_INV;
        }
        strcpy((char *)dsc->src, src);
    }
    else {
        dsc->src = src;
    }

    lv_res_t res = LV_RES_INV;

    lv_img_decoder_t * decoder;
    _LV_LL_READ(&LV_GC_ROOT(_lv_img_decoder_ll), decoder) {
        /*Info and Open callbacks are required*/
        if(decoder->info_cb == NULL || decoder->open_cb == NULL) continue;

        res = decoder->info_cb(decoder, src, &dsc->header);
        if(res != LV_RES_OK) continue;

        dsc->decoder = decoder;
        res = decoder->open_cb(decoder, dsc);

        /*Opened successfully. It is a good decoder for this image source*/
        if(res == LV_RES_OK) return res;

        /*Prepare for the next loop*/
        lv_memset_00(&dsc->header, sizeof(lv_img_header_t));

        dsc->error_msg = NULL;
        dsc->img_data  = NULL;
        dsc->user_data = NULL;
        dsc->time_to_open = 0;
    }

    if(dsc->src_type == LV_IMG_SRC_FILE)
        lv_mem_free((void *)dsc->src);

    return res;
}

/**
 * Read a line from an opened image
 * @param dsc pointer to `lv_img_decoder_dsc_t` used in `lv_img_decoder_open`
 * @param x start X coordinate (from left)
 * @param y start Y coordinate (from top)
 * @param len number of pixels to read
 * @param buf store the data here
 * @return LV_RES_OK: success; LV_RES_INV: an error occurred
 */
lv_res_t lv_img_decoder_read_line(lv_img_decoder_dsc_t * dsc, lv_coord_t x, lv_coord_t y, lv_coord_t len, uint8_t * buf)
{
    lv_res_t res = LV_RES_INV;
    if(dsc->decoder->read_line_cb) res = dsc->decoder->read_line_cb(dsc->decoder, dsc, x, y, len, buf);

    return res;
}

/**
 * Close a decoding session
 * @param dsc pointer to `lv_img_decoder_dsc_t` used in `lv_img_decoder_open`
 */
void lv_img_decoder_close(lv_img_decoder_dsc_t * dsc)
{
    if(dsc->decoder) {
        if(dsc->decoder->close_cb) dsc->decoder->close_cb(dsc->decoder, dsc);

        if(dsc->src_type == LV_IMG_SRC_FILE) {
            lv_mem_free((void *)dsc->src);
            dsc->src = NULL;
        }
    }
}

/**
 * Create a new image decoder
 * @return pointer to the new image decoder
 */
lv_img_decoder_t * lv_img_decoder_create(void)
{
    lv_img_decoder_t * decoder;
    decoder = _lv_ll_ins_head(&LV_GC_ROOT(_lv_img_decoder_ll));
    LV_ASSERT_MALLOC(decoder);
    if(decoder == NULL) return NULL;

    lv_memset_00(decoder, sizeof(lv_img_decoder_t));

    return decoder;
}

/**
 * Delete an image decoder
 * @param decoder pointer to an image decoder
 */
void lv_img_decoder_delete(lv_img_decoder_t * decoder)
{
    _lv_ll_remove(&LV_GC_ROOT(_lv_img_decoder_ll), decoder);
    lv_mem_free(decoder);
}

/**
 * Set a callback to get information about the image
 * @param decoder pointer to an image decoder
 * @param info_cb a function to collect info about an image (fill an `lv_img_header_t` struct)
 */
void lv_img_decoder_set_info_cb(lv_img_decoder_t * decoder, lv_img_decoder_info_f_t info_cb)
{
    decoder->info_cb = info_cb;
}

/**
 * Set a callback to open an image
 * @param decoder pointer to an image decoder
 * @param open_cb a function to open an image
 */
void lv_img_decoder_set_open_cb(lv_img_decoder_t * decoder, lv_img_decoder_open_f_t open_cb)
{
    decoder->open_cb = open_cb;
}

/**
 * Set a callback to a decoded line of an image
 * @param decoder pointer to an image decoder
 * @param read_line_cb a function to read a line of an image
 */
void lv_img_decoder_set_read_line_cb(lv_img_decoder_t * decoder, lv_img_decoder_read_line_f_t read_line_cb)
{
    decoder->read_line_cb = read_line_cb;
}

/**
 * Set a callback to close a decoding session. E.g. close files and free other resources.
 * @param decoder pointer to an image decoder
 * @param close_cb a function to close a decoding session
 */
void lv_img_decoder_set_close_cb(lv_img_decoder_t * decoder, lv_img_decoder_close_f_t close_cb)
{
    decoder->close_cb = close_cb;
}

/**
 * Get info about a built-in image
 * @param decoder the decoder where this function belongs
 * @param src the image source: pointer to an `lv_img_dsc_t` variable, a file path or a symbol
 * @param header store the image data here
 * @return LV_RES_OK: the info is successfully stored in `header`; LV_RES_INV: unknown format or other error.
 */
lv_res_t lv_img_decoder_built_in_info(lv_img_decoder_t * decoder, const void * src, lv_img_header_t * header)
{
    LV_UNUSED(decoder); /*Unused*/

    lv_img_src_t src_type = lv_img_src_get_type(src);
    if(src_type == LV_IMG_SRC_VARIABLE) {
        lv_img_cf_t cf = ((lv_img_dsc_t *)src)->header.cf;
        if(cf < CF_BUILT_IN_FIRST || cf > CF_BUILT_IN_LAST) return LV_RES_INV;

        header->w  = ((lv_img_dsc_t *)src)->header.w;
        header->h  = ((lv_img_dsc_t *)src)->header.h;
        header->cf = ((lv_img_dsc_t *)src)->header.cf;
    }
    else if(src_type == LV_IMG_SRC_FILE) {
        /*Support only "*.bin" files*/
        if(strcmp(lv_fs_get_ext(src), "bin")) return LV_RES_INV;

        lv_fs_file_t f;
        lv_fs_res_t res = lv_fs_open(&f, src, LV_FS_MODE_RD);
        if(res == LV_FS_RES_OK) {
            uint32_t rn;
            res = lv_fs_read(&f, header, sizeof(lv_img_header_t), &rn);
            lv_fs_close(&f);
            if(res != LV_FS_RES_OK || rn != sizeof(lv_img_header_t)) {
                LV_LOG_WARN("Image get info get read file header");
                return LV_RES_INV;
            }
        }

        if(header->cf < CF_BUILT_IN_FIRST || header->cf > CF_BUILT_IN_LAST) return LV_RES_INV;
    }
    else if(src_type == LV_IMG_SRC_SYMBOL) {
        /*The size depend on the font but it is unknown here. It should be handled outside of the
         *function*/
        header->w = 1;
        header->h = 1;
        /*Symbols always have transparent parts. Important because of cover check in the draw
         *function. The actual value doesn't matter because lv_draw_label will draw it*/
        header->cf = LV_IMG_CF_ALPHA_1BIT;
    }
    else {
        LV_LOG_WARN("Image get info found unknown src type");
        return LV_RES_INV;
    }
    return LV_RES_OK;
}

/**
 * Open a built in image
 * @param decoder the decoder where this function belongs
 * @param dsc pointer to decoder descriptor. `src`, `color` are already initialized in it.
 * @return LV_RES_OK: the info is successfully stored in `header`; LV_RES_INV: unknown format or other error.
 */
lv_res_t lv_img_decoder_built_in_open(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc)
{
    /*Open the file if it's a file*/
    if(dsc->src_type == LV_IMG_SRC_FILE) {
        /*Support only "*.bin" files*/
        if(strcmp(lv_fs_get_ext(dsc->src), "bin")) return LV_RES_INV;

        lv_fs_file_t f;
        lv_fs_res_t res = lv_fs_open(&f, dsc->src, LV_FS_MODE_RD);
        if(res != LV_FS_RES_OK) {
            LV_LOG_WARN("Built-in image decoder can't open the file");
            return LV_RES_INV;
        }

        /*If the file was open successfully save the file descriptor*/
        if(dsc->user_data == NULL) {
            dsc->user_data = lv_mem_alloc(sizeof(lv_img_decoder_built_in_data_t));
            LV_ASSERT_MALLOC(dsc->user_data);
            if(dsc->user_data == NULL) {
                LV_LOG_ERROR("img_decoder_built_in_open: out of memory");
                lv_fs_close(&f);
                return LV_RES_INV;
            }
            lv_memset_00(dsc->user_data, sizeof(lv_img_decoder_built_in_data_t));
        }

        lv_img_decoder_built_in_data_t * user_data = dsc->user_data;
        lv_memcpy_small(&user_data->f, &f, sizeof(f));
    }
    else if(dsc->src_type == LV_IMG_SRC_VARIABLE) {
        /*The variables should have valid data*/
        if(((lv_img_dsc_t *)dsc->src)->data == NULL) {
            return LV_RES_INV;
        }
    }

    lv_img_cf_t cf = dsc->header.cf;
    /*Process A8,  RGB565A8, need load file to ram after https://github.com/lvgl/lvgl/pull/3337*/
    if(cf == LV_IMG_CF_ALPHA_8BIT || cf == LV_IMG_CF_RGB565A8) {
        if(dsc->src_type == LV_IMG_SRC_VARIABLE) {
            /*In case of uncompressed formats the image stored in the ROM/RAM.
             *So simply give its pointer*/
            dsc->img_data = ((lv_img_dsc_t *)dsc->src)->data;
            return LV_RES_OK;
        }
        else {
            /*If it's a file, read all to memory*/
            uint32_t len = dsc->header.w * dsc->header.h;
            len *= cf == LV_IMG_CF_RGB565A8 ? 3 : 1;
            uint8_t * fs_buf = lv_mem_alloc(len);
            if(fs_buf == NULL) return LV_RES_INV;

            lv_img_decoder_built_in_data_t * user_data = dsc->user_data;
            lv_fs_seek(&user_data->f, 4, LV_FS_SEEK_SET); /*+4 to skip the header*/
            lv_fs_res_t res = lv_fs_read(&user_data->f, fs_buf, len, NULL);
            if(res != LV_FS_RES_OK) {
                lv_mem_free(fs_buf);
                return LV_RES_INV;
            }
            dsc->img_data = fs_buf;
            return LV_RES_OK;
        }
    }
    /*Process true color formats*/
    else if(cf == LV_IMG_CF_TRUE_COLOR || cf == LV_IMG_CF_TRUE_COLOR_ALPHA ||
            cf == LV_IMG_CF_TRUE_COLOR_CHROMA_KEYED) {
        if(dsc->src_type == LV_IMG_SRC_VARIABLE) {
            /*In case of uncompressed formats the image stored in the ROM/RAM.
             *So simply give its pointer*/
            dsc->img_data = ((lv_img_dsc_t *)dsc->src)->data;
            return LV_RES_OK;
        }
        else {
            /*If it's a file it need to be read line by line later*/
            return LV_RES_OK;
        }
    }
    /*Process indexed images. Build a palette*/
    else if(cf == LV_IMG_CF_INDEXED_1BIT || cf == LV_IMG_CF_INDEXED_2BIT || cf == LV_IMG_CF_INDEXED_4BIT ||
            cf == LV_IMG_CF_INDEXED_8BIT) {
        uint8_t px_size       = lv_img_cf_get_px_size(cf);
        uint32_t palette_size = 1 << px_size;

        /*Allocate the palette*/
        if(dsc->user_data == NULL) {
            dsc->user_data = lv_mem_alloc(sizeof(lv_img_decoder_built_in_data_t));
            LV_ASSERT_MALLOC(dsc->user_data);
            if(dsc->user_data == NULL) {
                LV_LOG_ERROR("img_decoder_built_in_open: out of memory");
                return LV_RES_INV;
            }
            lv_memset_00(dsc->user_data, sizeof(lv_img_decoder_built_in_data_t));
        }

        lv_img_decoder_built_in_data_t * user_data = dsc->user_data;
        user_data->palette                         = lv_mem_alloc(palette_size * sizeof(lv_color_t));
        LV_ASSERT_MALLOC(user_data->palette);
        user_data->opa                             = lv_mem_alloc(palette_size * sizeof(lv_opa_t));
        LV_ASSERT_MALLOC(user_data->opa);
        if(user_data->palette == NULL || user_data->opa == NULL) {
            LV_LOG_ERROR("img_decoder_built_in_open: out of memory");
            lv_img_decoder_built_in_close(decoder, dsc);
            return LV_RES_INV;
        }

        if(dsc->src_type == LV_IMG_SRC_FILE) {
            /*Read the palette from file*/
            lv_fs_seek(&user_data->f, 4, LV_FS_SEEK_SET); /*Skip the header*/
            lv_color32_t cur_color;
            uint32_t i;
            for(i = 0; i < palette_size; i++) {
                lv_fs_read(&user_data->f, &cur_color, sizeof(lv_color32_t), NULL);
                user_data->palette[i] = lv_color_make(cur_color.ch.red, cur_color.ch.green, cur_color.ch.blue);
                user_data->opa[i]     = cur_color.ch.alpha;
            }
        }
        else {
            /*The palette begins in the beginning of the image data. Just point to it.*/
            lv_color32_t * palette_p = (lv_color32_t *)((lv_img_dsc_t *)dsc->src)->data;

            uint32_t i;
            for(i = 0; i < palette_size; i++) {
                user_data->palette[i] = lv_color_make(palette_p[i].ch.red, palette_p[i].ch.green, palette_p[i].ch.blue);
                user_data->opa[i]     = palette_p[i].ch.alpha;
            }
        }

        return LV_RES_OK;
    }
    /*Alpha indexed images.*/
    else if(cf == LV_IMG_CF_ALPHA_1BIT || cf == LV_IMG_CF_ALPHA_2BIT || cf == LV_IMG_CF_ALPHA_4BIT) {
        return LV_RES_OK; /*Nothing to process*/
    }
    /*Unknown format. Can't decode it.*/
    else {
        /*Free the potentially allocated memories*/
        lv_img_decoder_built_in_close(decoder, dsc);

        LV_LOG_WARN("Image decoder open: unknown color format");
        return LV_RES_INV;
    }
}

/**
 * Decode `len` pixels starting from the given `x`, `y` coordinates and store them in `buf`.
 * Required only if the "open" function can't return with the whole decoded pixel array.
 * @param decoder pointer to the decoder the function associated with
 * @param dsc pointer to decoder descriptor
 * @param x start x coordinate
 * @param y start y coordinate
 * @param len number of pixels to decode
 * @param buf a buffer to store the decoded pixels
 * @return LV_RES_OK: ok; LV_RES_INV: failed
 */
lv_res_t lv_img_decoder_built_in_read_line(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc, lv_coord_t x,
                                           lv_coord_t y, lv_coord_t len, uint8_t * buf)
{
    LV_UNUSED(decoder); /*Unused*/

    lv_res_t res = LV_RES_INV;

    if(dsc->header.cf == LV_IMG_CF_TRUE_COLOR || dsc->header.cf == LV_IMG_CF_TRUE_COLOR_ALPHA ||
       dsc->header.cf == LV_IMG_CF_TRUE_COLOR_CHROMA_KEYED) {
        /*For TRUE_COLOR images read line required only for files.
         *For variables the image data was returned in `open`*/
        if(dsc->src_type == LV_IMG_SRC_FILE) {
            res = lv_img_decoder_built_in_line_true_color(dsc, x, y, len, buf);
        }
    }
    else if(dsc->header.cf == LV_IMG_CF_ALPHA_1BIT || dsc->header.cf == LV_IMG_CF_ALPHA_2BIT ||
            dsc->header.cf == LV_IMG_CF_ALPHA_4BIT || dsc->header.cf == LV_IMG_CF_ALPHA_8BIT) {
        res = lv_img_decoder_built_in_line_alpha(dsc, x, y, len, buf);
    }
    else if(dsc->header.cf == LV_IMG_CF_INDEXED_1BIT || dsc->header.cf == LV_IMG_CF_INDEXED_2BIT ||
            dsc->header.cf == LV_IMG_CF_INDEXED_4BIT || dsc->header.cf == LV_IMG_CF_INDEXED_8BIT) {
        res = lv_img_decoder_built_in_line_indexed(dsc, x, y, len, buf);
    }
    else {
        LV_LOG_WARN("Built-in image decoder read not supports the color format");
        return LV_RES_INV;
    }

    return res;
}

/**
 * Close the pending decoding. Free resources etc.
 * @param decoder pointer to the decoder the function associated with
 * @param dsc pointer to decoder descriptor
 */
void lv_img_decoder_built_in_close(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc)
{
    LV_UNUSED(decoder); /*Unused*/

    lv_img_decoder_built_in_data_t * user_data = dsc->user_data;
    if(user_data) {
        if(dsc->src_type == LV_IMG_SRC_FILE) {
            lv_fs_close(&user_data->f);
        }
        if(user_data->palette) lv_mem_free(user_data->palette);
        if(user_data->opa) lv_mem_free(user_data->opa);

        lv_mem_free(user_data);
        dsc->user_data = NULL;
    }
}

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

static lv_res_t lv_img_decoder_built_in_line_true_color(lv_img_decoder_dsc_t * dsc, lv_coord_t x, lv_coord_t y,
                                                        lv_coord_t len, uint8_t * buf)
{
    lv_img_decoder_built_in_data_t * user_data = dsc->user_data;
    lv_fs_res_t res;
    uint8_t px_size = lv_img_cf_get_px_size(dsc->header.cf);

    uint32_t pos = ((y * dsc->header.w + x) * px_size) >> 3;
    pos += 4; /*Skip the header*/
    res = lv_fs_seek(&user_data->f, pos, LV_FS_SEEK_SET);
    if(res != LV_FS_RES_OK) {
        LV_LOG_WARN("Built-in image decoder seek failed");
        return LV_RES_INV;
    }
    uint32_t btr = len * (px_size >> 3);
    uint32_t br  = 0;
    res = lv_fs_read(&user_data->f, buf, btr, &br);
    if(res != LV_FS_RES_OK || btr != br) {
        LV_LOG_WARN("Built-in image decoder read failed");
        return LV_RES_INV;
    }

    return LV_RES_OK;
}

static lv_res_t lv_img_decoder_built_in_line_alpha(lv_img_decoder_dsc_t * dsc, lv_coord_t x, lv_coord_t y,
                                                   lv_coord_t len, uint8_t * buf)
{
    const lv_opa_t alpha1_opa_table[2]  = {0, 255};          /*Opacity mapping with bpp = 1 (Just for compatibility)*/
    const lv_opa_t alpha2_opa_table[4]  = {0, 85, 170, 255}; /*Opacity mapping with bpp = 2*/
    const lv_opa_t alpha4_opa_table[16] = {0,  17, 34,  51,  /*Opacity mapping with bpp = 4*/
                                           68, 85, 102, 119, 136, 153, 170, 187, 204, 221, 238, 255
                                          };

    /*Simply fill the buffer with the color. Later only the alpha value will be modified.*/
    lv_color_t bg_color = dsc->color;
    lv_coord_t i;
    for(i = 0; i < len; i++) {
#if LV_COLOR_DEPTH == 8 || LV_COLOR_DEPTH == 1
        buf[i * LV_IMG_PX_SIZE_ALPHA_BYTE] = bg_color.full;
#elif LV_COLOR_DEPTH == 16
        /*Because of Alpha byte 16 bit color can start on odd address which can cause crash*/
        buf[i * LV_IMG_PX_SIZE_ALPHA_BYTE] = bg_color.full & 0xFF;
        buf[i * LV_IMG_PX_SIZE_ALPHA_BYTE + 1] = (bg_color.full >> 8) & 0xFF;
#elif LV_COLOR_DEPTH == 32
        *((uint32_t *)&buf[i * LV_IMG_PX_SIZE_ALPHA_BYTE]) = bg_color.full;
#else
#error "Invalid LV_COLOR_DEPTH. Check it in lv_conf.h"
#endif
    }

    const lv_opa_t * opa_table = NULL;
    uint8_t px_size            = lv_img_cf_get_px_size(dsc->header.cf);
    uint16_t mask              = (1 << px_size) - 1; /*E.g. px_size = 2; mask = 0x03*/

    lv_coord_t w = 0;
    uint32_t ofs = 0;
    int8_t pos   = 0;
    switch(dsc->header.cf) {
        case LV_IMG_CF_ALPHA_1BIT:
            w = (dsc->header.w + 7) >> 3; /*E.g. w = 20 -> w = 2 + 1*/
            ofs += w * y + (x >> 3); /*First pixel*/
            pos = 7 - (x & 0x7);
            opa_table = alpha1_opa_table;
            break;
        case LV_IMG_CF_ALPHA_2BIT:
            w = (dsc->header.w + 3) >> 2; /*E.g. w = 13 -> w = 3 + 1 (bytes)*/
            ofs += w * y + (x >> 2); /*First pixel*/
            pos = 6 - (x & 0x3) * 2;
            opa_table = alpha2_opa_table;
            break;
        case LV_IMG_CF_ALPHA_4BIT:
            w = (dsc->header.w + 1) >> 1; /*E.g. w = 13 -> w = 6 + 1 (bytes)*/
            ofs += w * y + (x >> 1); /*First pixel*/
            pos = 4 - (x & 0x1) * 4;
            opa_table = alpha4_opa_table;
            break;
        case LV_IMG_CF_ALPHA_8BIT:
            w = dsc->header.w; /*E.g. x = 7 -> w = 7 (bytes)*/
            ofs += w * y + x;  /*First pixel*/
            pos = 0;
            break;
    }

    lv_img_decoder_built_in_data_t * user_data = dsc->user_data;
    uint8_t * fs_buf = lv_mem_buf_get(w);
    if(fs_buf == NULL) return LV_RES_INV;

    const uint8_t * data_tmp = NULL;
    if(dsc->src_type == LV_IMG_SRC_VARIABLE) {
        const lv_img_dsc_t * img_dsc = dsc->src;

        data_tmp = img_dsc->data + ofs;
    }
    else {
        lv_fs_seek(&user_data->f, ofs + 4, LV_FS_SEEK_SET); /*+4 to skip the header*/
        lv_fs_read(&user_data->f, fs_buf, w, NULL);
        data_tmp = fs_buf;
    }

    for(i = 0; i < len; i++) {
        uint8_t val_act = (*data_tmp >> pos) & mask;

        buf[i * LV_IMG_PX_SIZE_ALPHA_BYTE + LV_IMG_PX_SIZE_ALPHA_BYTE - 1] =
            dsc->header.cf == LV_IMG_CF_ALPHA_8BIT ? val_act : opa_table[val_act];

        pos -= px_size;
        if(pos < 0) {
            pos = 8 - px_size;
            data_tmp++;
        }
    }
    lv_mem_buf_release(fs_buf);
    return LV_RES_OK;
}

static lv_res_t lv_img_decoder_built_in_line_indexed(lv_img_decoder_dsc_t * dsc, lv_coord_t x, lv_coord_t y,
                                                     lv_coord_t len, uint8_t * buf)
{
    uint8_t px_size = lv_img_cf_get_px_size(dsc->header.cf);
    uint16_t mask   = (1 << px_size) - 1; /*E.g. px_size = 2; mask = 0x03*/

    lv_coord_t w = 0;
    int8_t pos   = 0;
    uint32_t ofs = 0;
    switch(dsc->header.cf) {
        case LV_IMG_CF_INDEXED_1BIT:
            w = (dsc->header.w + 7) >> 3; /*E.g. w = 20 -> w = 2 + 1*/
            ofs += w * y + (x >> 3); /*First pixel*/
            ofs += 8;                /*Skip the palette*/
            pos = 7 - (x & 0x7);
            break;
        case LV_IMG_CF_INDEXED_2BIT:
            w = (dsc->header.w + 3) >> 2; /*E.g. w = 13 -> w = 3 + 1 (bytes)*/
            ofs += w * y + (x >> 2); /*First pixel*/
            ofs += 16;               /*Skip the palette*/
            pos = 6 - (x & 0x3) * 2;
            break;
        case LV_IMG_CF_INDEXED_4BIT:
            w = (dsc->header.w + 1) >> 1; /*E.g. w = 13 -> w = 6 + 1 (bytes)*/
            ofs += w * y + (x >> 1); /*First pixel*/
            ofs += 64;               /*Skip the palette*/
            pos = 4 - (x & 0x1) * 4;
            break;
        case LV_IMG_CF_INDEXED_8BIT:
            w = dsc->header.w; /*E.g. x = 7 -> w = 7 (bytes)*/
            ofs += w * y + x;  /*First pixel*/
            ofs += 1024;       /*Skip the palette*/
            pos = 0;
            break;
    }

    lv_img_decoder_built_in_data_t * user_data = dsc->user_data;

    uint8_t * fs_buf = lv_mem_buf_get(w);
    if(fs_buf == NULL) return LV_RES_INV;
    const uint8_t * data_tmp = NULL;
    if(dsc->src_type == LV_IMG_SRC_VARIABLE) {
        const lv_img_dsc_t * img_dsc = dsc->src;
        data_tmp                     = img_dsc->data + ofs;
    }
    else {
        lv_fs_seek(&user_data->f, ofs + 4, LV_FS_SEEK_SET); /*+4 to skip the header*/
        lv_fs_read(&user_data->f, fs_buf, w, NULL);
        data_tmp = fs_buf;
    }

    lv_coord_t i;
    for(i = 0; i < len; i++) {
        uint8_t val_act = (*data_tmp >> pos) & mask;

        lv_color_t color = user_data->palette[val_act];
#if LV_COLOR_DEPTH == 8 || LV_COLOR_DEPTH == 1
        buf[i * LV_IMG_PX_SIZE_ALPHA_BYTE] = color.full;
#elif LV_COLOR_DEPTH == 16
        /*Because of Alpha byte 16 bit color can start on odd address which can cause crash*/
        buf[i * LV_IMG_PX_SIZE_ALPHA_BYTE] = color.full & 0xFF;
        buf[i * LV_IMG_PX_SIZE_ALPHA_BYTE + 1] = (color.full >> 8) & 0xFF;
#elif LV_COLOR_DEPTH == 32
        *((uint32_t *)&buf[i * LV_IMG_PX_SIZE_ALPHA_BYTE]) = color.full;
#else
#error "Invalid LV_COLOR_DEPTH. Check it in lv_conf.h"
#endif
        buf[i * LV_IMG_PX_SIZE_ALPHA_BYTE + LV_IMG_PX_SIZE_ALPHA_BYTE - 1] = user_data->opa[val_act];

        pos -= px_size;
        if(pos < 0) {
            pos = 8 - px_size;
            data_tmp++;
        }
    }
    lv_mem_buf_release(fs_buf);
    return LV_RES_OK;
}