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lv_png.c
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lv_png.c
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/**
* @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(&fn[strlen(fn) - 3], "png")) { /*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);
if(rn != 8) return LV_RES_INV;
lv_fs_close(&f);
/*Save the data in the header*/
header->always_zero = 0;
header->cf = LV_IMG_CF_RAW_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 uint8_t magic[] = {0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a};
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(&fn[strlen(fn) - 3], "png")) { /*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) {
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) {
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*/