Tiny JPEG Decompressor (TJpgDec)

Tiny JPEG Decompressor is an LVGL interface to the TJpgDec library — a generic JPEG image decompressor module that highly optimized for small embedded systems. It works with very low memory consumption, so that it can be incorporated into tiny microcontrollers, such as AVR, 8051, PIC, Z80, Cortex-M0, etc..

For a detailed introduction, see: TJpgDec.

Overview

Features and restrictions:

JPEG is decoded in 8x8 tiles.
Only baseline JPEG files are supported (no progressive JPEG support).
Read from file and C array are implemented.
Only the required portions of the JPEG images are decoded, therefore they cannot be zoomed or rotated.

Usage

Set LV_USE_TJPGD to 1 in lv_conf.h. LVGL will register a new image decoder automatically so JPEG files can be used directly as image sources.

For example:

lv_image_set_src(my_img, "S:path/to/picture.jpg");

Note

A file system driver needs to be registered to open images from files. To do so, follow the instructions in File System (lv_fs_drv).

Converter

Converting JPEG to C array

Use lvgl online tool https://lvgl.io/tools/imageconverter
Color format = RAW, output format = C Array

Example

Load a JPG image

#include "../../lv_examples.h"
#if LV_USE_TJPGD && LV_BUILD_EXAMPLES

/**
 * Load a JPG image
 */
void lv_example_tjpgd_1(void)
{
    lv_obj_t * wp;

    wp = lv_image_create(lv_screen_active());
    /* Assuming a File system is attached to letter 'A'
     * E.g. set LV_USE_FS_STDIO 'A' in lv_conf.h */
    lv_image_set_src(wp, "A:test_img_lvgl_logo.jpg");
    lv_obj_center(wp);
}

#endif

API

lv_tjpgd.h

tjpgd.h

tjpgdcnf.h