/**
  * @file lv_png.c
  *
  */
 
 /*********************
  *      INCLUDES
  *********************/
 #include "../../../lvgl.h"
 #if LV_USE_PNG
 
 #include "lv_png.h"
 #include "lodepng.h"
 #include <stdlib.h>
 
 /*********************
  *      DEFINES
  *********************/
 
 /**********************
  *      TYPEDEFS
  **********************/
 
 /**********************
  *  STATIC PROTOTYPES
  **********************/
 static lv_res_t decoder_info(struct _lv_img_decoder_t * decoder, const void * src, lv_img_header_t * header);
 static lv_res_t decoder_open(lv_img_decoder_t * dec, lv_img_decoder_dsc_t * dsc);
 static void decoder_close(lv_img_decoder_t * dec, lv_img_decoder_dsc_t * dsc);
 static void convert_color_depth(uint8_t * img, uint32_t px_cnt);
 
 /**********************
  *  STATIC VARIABLES
  **********************/
 
 /**********************
  *      MACROS
  **********************/
 
 /**********************
  *   GLOBAL FUNCTIONS
  **********************/
 
 /**
  * Register the PNG decoder functions in LVGL
  */
 void lv_png_init(void)
 {
     lv_img_decoder_t * dec = lv_img_decoder_create();
     lv_img_decoder_set_info_cb(dec, decoder_info);
     lv_img_decoder_set_open_cb(dec, decoder_open);
     lv_img_decoder_set_close_cb(dec, decoder_close);
 }
 
 /**********************
  *   STATIC FUNCTIONS
  **********************/
 
 /**
  * Get info about a PNG image
  * @param src can be file name or pointer to a C array
  * @param header store the info here
  * @return LV_RES_OK: no error; LV_RES_INV: can't get the info
  */
 static lv_res_t decoder_info(struct _lv_img_decoder_t * decoder, const void * src, lv_img_header_t * header)
 {
     (void) decoder; /*Unused*/
     lv_img_src_t src_type = lv_img_src_get_type(src);          /*Get the source type*/
 
     /*If it's a PNG file...*/
     if(src_type == LV_IMG_SRC_FILE) {
         const char * fn = src;
         if(strcmp(lv_fs_get_ext(fn), "png") == 0) {              /*Check the extension*/
 
             /* Read the width and height from the file. They have a constant location:
              * [16..23]: width
              * [24..27]: height
              */
             uint32_t size[2];
             lv_fs_file_t f;
             lv_fs_res_t res = lv_fs_open(&f, fn, LV_FS_MODE_RD);
             if(res != LV_FS_RES_OK) return LV_RES_INV;
 
             lv_fs_seek(&f, 16, LV_FS_SEEK_SET);
 
             uint32_t rn;
             lv_fs_read(&f, &size, 8, &rn);
             lv_fs_close(&f);
 
             if(rn != 8) return LV_RES_INV;
 
             /*Save the data in the header*/
             header->always_zero = 0;
             header->cf = LV_IMG_CF_TRUE_COLOR_ALPHA;
             /*The width and height are stored in Big endian format so convert them to little endian*/
             header->w = (lv_coord_t)((size[0] & 0xff000000) >> 24) + ((size[0] & 0x00ff0000) >> 8);
             header->h = (lv_coord_t)((size[1] & 0xff000000) >> 24) + ((size[1] & 0x00ff0000) >> 8);
 
             return LV_RES_OK;
         }
     }
     /*If it's a PNG file in a  C array...*/
     else if(src_type == LV_IMG_SRC_VARIABLE) {
         const lv_img_dsc_t * img_dsc = src;
         const uint32_t data_size = img_dsc->data_size;
         const uint8_t magic[] = {0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a};
         if(data_size < sizeof(magic)) return LV_RES_INV;
         if(memcmp(magic, img_dsc->data, sizeof(magic))) return LV_RES_INV;
         header->always_zero = 0;
         header->cf = img_dsc->header.cf;       /*Save the color format*/
         header->w = img_dsc->header.w;         /*Save the color width*/
         header->h = img_dsc->header.h;         /*Save the color height*/
         return LV_RES_OK;
     }
 
     return LV_RES_INV;         /*If didn't succeeded earlier then it's an error*/
 }
 
 
 /**
  * Open a PNG image and return the decided image
  * @param src can be file name or pointer to a C array
  * @param style style of the image object (unused now but certain formats might use it)
  * @return pointer to the decoded image or `LV_IMG_DECODER_OPEN_FAIL` if failed
  */
 static lv_res_t decoder_open(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc)
 {
 
     (void) decoder; /*Unused*/
     uint32_t error;                 /*For the return values of PNG decoder functions*/
 
     uint8_t * img_data = NULL;
 
     /*If it's a PNG file...*/
     if(dsc->src_type == LV_IMG_SRC_FILE) {
         const char * fn = dsc->src;
         if(strcmp(lv_fs_get_ext(fn), "png") == 0) {              /*Check the extension*/
 
             /*Load the PNG file into buffer. It's still compressed (not decoded)*/
             unsigned char * png_data;      /*Pointer to the loaded data. Same as the original file just loaded into the RAM*/
             size_t png_data_size;          /*Size of `png_data` in bytes*/
 
             error = lodepng_load_file(&png_data, &png_data_size, fn);   /*Load the file*/
             if(error) {
                 LV_LOG_WARN("error %u: %s\n", error, lodepng_error_text(error));
                 return LV_RES_INV;
             }
 
             /*Decode the PNG image*/
             uint32_t png_width;             /*Will be the width of the decoded image*/
             uint32_t png_height;            /*Will be the width of the decoded image*/
 
             /*Decode the loaded image in ARGB8888 */
             error = lodepng_decode32(&img_data, &png_width, &png_height, png_data, png_data_size);
             lv_mem_free(png_data); /*Free the loaded file*/
             if(error) {
                 if(img_data != NULL) {
                     lv_mem_free(img_data);
                 }
                 LV_LOG_WARN("error %u: %s\n", error, lodepng_error_text(error));
                 return LV_RES_INV;
             }
 
             /*Convert the image to the system's color depth*/
             convert_color_depth(img_data,  png_width * png_height);
             dsc->img_data = img_data;
             return LV_RES_OK;     /*The image is fully decoded. Return with its pointer*/
         }
     }
     /*If it's a PNG file in a  C array...*/
     else if(dsc->src_type == LV_IMG_SRC_VARIABLE) {
         const lv_img_dsc_t * img_dsc = dsc->src;
         uint32_t png_width;             /*No used, just required by he decoder*/
         uint32_t png_height;            /*No used, just required by he decoder*/
 
         /*Decode the image in ARGB8888 */
         error = lodepng_decode32(&img_data, &png_width, &png_height, img_dsc->data, img_dsc->data_size);
 
         if(error) {
             if(img_data != NULL) {
                 lv_mem_free(img_data);
             }
             return LV_RES_INV;
         }
 
         /*Convert the image to the system's color depth*/
         convert_color_depth(img_data,  png_width * png_height);
 
         dsc->img_data = img_data;
         return LV_RES_OK;     /*Return with its pointer*/
     }
 
     return LV_RES_INV;    /*If not returned earlier then it failed*/
 }
 
 /**
  * Free the allocated resources
  */
 static void decoder_close(lv_img_decoder_t * decoder, lv_img_decoder_dsc_t * dsc)
 {
     LV_UNUSED(decoder); /*Unused*/
     if(dsc->img_data) {
         lv_mem_free((uint8_t *)dsc->img_data);
         dsc->img_data = NULL;
     }
 }
 
 /**
  * If the display is not in 32 bit format (ARGB888) then covert the image to the current color depth
  * @param img the ARGB888 image
  * @param px_cnt number of pixels in `img`
  */
 static void convert_color_depth(uint8_t * img, uint32_t px_cnt)
 {
 #if LV_COLOR_DEPTH == 32
     lv_color32_t * img_argb = (lv_color32_t *)img;
     lv_color_t c;
     lv_color_t * img_c = (lv_color_t *) img;
     uint32_t i;
     for(i = 0; i < px_cnt; i++) {
         c = lv_color_make(img_argb[i].ch.red, img_argb[i].ch.green, img_argb[i].ch.blue);
         img_c[i].ch.red = c.ch.blue;
         img_c[i].ch.blue = c.ch.red;
     }
 #elif LV_COLOR_DEPTH == 16
     lv_color32_t * img_argb = (lv_color32_t *)img;
     lv_color_t c;
     uint32_t i;
     for(i = 0; i < px_cnt; i++) {
         c = lv_color_make(img_argb[i].ch.blue, img_argb[i].ch.green, img_argb[i].ch.red);
         img[i * 3 + 2] = img_argb[i].ch.alpha;
         img[i * 3 + 1] = c.full >> 8;
         img[i * 3 + 0] = c.full & 0xFF;
     }
 #elif LV_COLOR_DEPTH == 8
     lv_color32_t * img_argb = (lv_color32_t *)img;
     lv_color_t c;
     uint32_t i;
     for(i = 0; i < px_cnt; i++) {
         c = lv_color_make(img_argb[i].ch.red, img_argb[i].ch.green, img_argb[i].ch.blue);
         img[i * 2 + 1] = img_argb[i].ch.alpha;
         img[i * 2 + 0] = c.full;
     }
 #elif LV_COLOR_DEPTH == 1
     lv_color32_t * img_argb = (lv_color32_t *)img;
     uint8_t b;
     uint32_t i;
     for(i = 0; i < px_cnt; i++) {
         b = img_argb[i].ch.red | img_argb[i].ch.green | img_argb[i].ch.blue;
         img[i * 2 + 1] = img_argb[i].ch.alpha;
         img[i * 2 + 0] = b > 128 ? 1 : 0;
     }
 #endif
 }
 
 #endif /*LV_USE_PNG*/
 
 

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