feat(image): add custom RLE decoder (#4332)

Signed-off-by: Xu Xingliang <xuxingliang@xiaomi.com>

Kconfig

@@ -1115,6 +1115,9 @@ menu "LVGL configuration"
 		config LV_USE_GIF
 			bool "GIF decoder library"
 
+		config LV_USE_RLE
+			bool "RLE compressed bin image decoder library"
+
 		config LV_USE_QRCODE
 			bool "QR code library"
 

docs/libs/index.rst

@@ -19,3 +19,4 @@
     barcode
     rlottie
     ffmpeg
+    rle

docs/libs/rle.rst

@@ -0,0 +1,84 @@
+RLE Decoder
+===========
+
+The RLE Decoder is a part of LVGL that is responsible for decoding RLE
+compressed original LVGL binary files. The file name suffix is always set
+to '.rle' and the file header is added with another 64-bit value that
+includes a 32-bit magic number and 32-bit RLE information.
+
+The decoder supports both variable and file as image sources. The original
+binary data is directly decompressed to RAM, and further decoded by LVGL's
+built-in decoder.
+
+Benefits
+--------
+
+Based on test result from a watch project. Most of the images can be compressed
+to save more than 70% space as show in below statistic. It shows the file count
+of every compress level. For rare conditions, RLE compress may increase the file
+size if there's no large repetition in data.
+
+.. image:: /libs/rle-compress-statistics.png
+   :alt: RLE compress statistics from a watch project
+   :align: center
+
+
+Theory
+------
+
+The RLE algorithm is a simple compression algorithm that is based on the fact that
+the for many pixels, the color is the same. The algorithm simply counts how many
+repeated data are there and store the count value and the color value.
+If the coming pixels are not repeated, it stores the non-repeat count value and
+original color value. For more details, the script used to compress the image
+can be found from `lvgl/script/LVGLImage.py`.
+
+.. code:: python
+
+    def rle_compress(self, data: bytearray, blksize: int, threshold=16):
+        index = 0
+        data_len = len(data)
+        compressed_data = []
+        while index < data_len:
+            memview = memoryview(data)
+            repeat_cnt = self.get_repeat_count(
+                memview[index:], blksize)
+            if repeat_cnt == 0:
+                # done
+                break
+            elif repeat_cnt < threshold:
+                nonrepeat_cnt = self.get_nonrepeat_count(
+                    memview[index:], blksize, threshold)
+                ctrl_byte = uint8_t(nonrepeat_cnt | 0x80)
+                compressed_data.append(ctrl_byte)
+                compressed_data.append(
+                    memview[index: index + nonrepeat_cnt*blksize])
+                index += nonrepeat_cnt * blksize
+            else:
+                ctrl_byte = uint8_t(repeat_cnt)
+                compressed_data.append(ctrl_byte)
+                compressed_data.append(memview[index: index + blksize])
+                index += repeat_cnt * blksize
+
+        return b"".join(compressed_data)
+
+
+Usage
+-----
+
+To use the RLE Decoder, ensure that `LV_USE_RLE` is defined and set to `1`.
+The RLE image can be used same as other images.
+
+.. code:: c
+
+   lv_image_set_src(img, "path/to/image.rle");
+
+Generate RLE images
+-------------------
+
+The image can be directly generated using script `lvgl/script/LVGLImage.py`
+
+
+.. code:: bash
+
+   ./script/LVGLImage.py --ofmt RLE --cf I8 cogwheel.png

env_support/cmsis-pack/LVGL.lvgl.pdsc

@@ -81,7 +81,7 @@
     </release>
     <release date="2022-08-30" version="1.0.8" url="https://github.com/lvgl/lvgl/raw/eb2e296d23b009aca7daf0e9be062d05b4b0048a/env_support/cmsis-pack/LVGL.lvgl.1.0.8.pack">
       - LVGL 9.0.0-dev
-      - Add the binding for pikascript (an ultra-light-weight python VM) 
+      - Add the binding for pikascript (an ultra-light-weight python VM)
       - Montyly update for August
     </release>
     <release date="2022-07-29" version="1.0.7" url="https://github.com/lvgl/lvgl/raw/b454a66e0be85976385c81cf9c9025f272a66f5d/env_support/cmsis-pack/LVGL.lvgl.1.0.7.pack">
@@ -212,7 +212,7 @@
             <description>Require Arm-2D Support</description>
             <require Cclass="Acceleration" Cgroup="Arm-2D"/>
         </condition>
-        
+
         <condition id="LVGL-GPU-Arm-2D">
             <description>Enable LVGL Arm-2D GPU Support</description>
             <require Cclass="LVGL" Cgroup="lvgl" Csub="Essential"/>
@@ -223,7 +223,7 @@
             <deny Cclass="LVGL" Cgroup="lvgl" Csub="GPU NXP-VGLite"/>
             <deny Cclass="LVGL" Cgroup="lvgl" Csub="GPU GD32-IPA"/>
         </condition>
-        
+
         <condition id="LVGL-GPU-STM32-DMA2D">
             <description>Enable LVGL Arm-2D GPU Support</description>
             <require Cclass="LVGL" Cgroup="lvgl" Csub="Essential"/>
@@ -234,7 +234,7 @@
             <deny Cclass="LVGL" Cgroup="lvgl" Csub="GPU NXP-VGLite"/>
             <deny Cclass="LVGL" Cgroup="lvgl" Csub="GPU GD32-IPA"/>
         </condition>
-        
+
         <condition id="LVGL-GPU-SWM341-DMA2D">
             <description>Enable LVGL Arm-2D GPU Support</description>
             <require Cclass="LVGL" Cgroup="lvgl" Csub="Essential"/>
@@ -245,7 +245,7 @@
             <deny Cclass="LVGL" Cgroup="lvgl" Csub="GPU NXP-VGLite"/>
             <deny Cclass="LVGL" Cgroup="lvgl" Csub="GPU GD32-IPA"/>
         </condition>
-        
+
         <condition id="LVGL-GPU-NXP-PXP">
             <description>Enable LVGL Arm-2D GPU Support</description>
             <require Cclass="LVGL" Cgroup="lvgl" Csub="Essential"/>
@@ -256,7 +256,7 @@
             <deny Cclass="LVGL" Cgroup="lvgl" Csub="GPU NXP-VGLite"/>
             <deny Cclass="LVGL" Cgroup="lvgl" Csub="GPU GD32-IPA"/>
         </condition>
-        
+
         <condition id="LVGL-GPU-NXP-VGLite">
             <description>Enable LVGL Arm-2D GPU Support</description>
             <require Cclass="LVGL" Cgroup="lvgl" Csub="Essential"/>
@@ -267,7 +267,7 @@
             <!--<deny Cclass="LVGL" Cgroup="lvgl" Csub="GPU NXP-VGLite"/>-->
             <deny Cclass="LVGL" Cgroup="lvgl" Csub="GPU GD32-IPA"/>
         </condition>
-        
+
         <condition id="LVGL-GPU-GD32-IPA">
             <description>Enable LVGL Arm-2D GPU Support</description>
             <require Cclass="LVGL" Cgroup="lvgl" Csub="Essential"/>
@@ -500,7 +500,7 @@
                 <file category="sourceC"            name="lv_cmsis_pack.c" attr="config" version="1.0.0" />
                 <file category="header"             name="lvgl.h" />
                 <file category="doc"                name="README.md"/>
-                
+
                 <!-- code template -->
                 <file category="header"       name="examples/porting/lv_port_disp_template.h" attr="template" select="Display port template" version="2.0.0"/>
                 <file category="sourceC"      name="examples/porting/lv_port_disp_template.c" attr="template" select="Display port template" version="2.0.0"/>
@@ -782,6 +782,21 @@
 #define LV_USE_GIF         1
               </RTE_Components_h>
 
+/*! \brief enable RLE compressed bin image decoder support */
+#define LV_USE_RLE          1
+              </RTE_Components_h>
+
+            </component>
+
+            <component Cgroup="lvgl" Csub="Libs RLE"  condition="LVGL-Essential">
+              <description>Add RLE compressed bin image decoder support</description>
+              <files>
+                <!-- src/libs/rle -->
+                <file category="sourceC"    name="src/libs/rle/lv_rle_decoder.c" />
+              </files>
+
+              <RTE_Components_h>
+
             </component>
 
             <component Cgroup="lvgl" Csub="Libs sJPG"  condition="LVGL-Essential">
@@ -799,7 +814,7 @@
               </RTE_Components_h>
 
             </component>
-      
+
             <component Cgroup="lvgl" Csub="Libs QRCode"  condition="LVGL-Essential">
               <description>Add QRCode support</description>
               <files>

env_support/cmsis-pack/README.md

@@ -6,7 +6,7 @@
 
 1. Copy the **lv_conf_template.h** to '**cmsis-pack**' directory
 
-2. Set the macro protector to '1' 
+2. Set the macro protector to '1'
 
 ```c
 ...
@@ -47,7 +47,7 @@ remove the misleading guide above this code segment.
    #define LV_STRING_INCLUDE <string.h>
    ```
 
-   
+
 
 5. Remove macro definitions for
 
@@ -135,7 +135,7 @@ Make sure `LV_MEM_SIZE` is no less than `(64*1024U)`.
    #if LV_USE_DEMO_WIDGETS
        #define LV_DEMO_WIDGETS_SLIDESHOW 0
    #endif
-   
+
    /*Benchmark your system*/
    #if LV_USE_DEMO_BENCHMARK
        /*Use RGB565A8 images with 16 bit color depth instead of ARGB8565*/
@@ -143,7 +143,7 @@ Make sure `LV_MEM_SIZE` is no less than `(64*1024U)`.
    #endif
    ```
 
-   
+
 
 10. Remove following macro definitions in the `3rd party libraries` section:
 
@@ -153,6 +153,7 @@ Make sure `LV_MEM_SIZE` is no less than `(64*1024U)`.
     - \#define LV_USE_FS_FATFS 0
     - \#define LV_USE_LODEPNG 0
     - \#define LV_USE_BMP 0
+    - \#define LV_USE_RLE 0
     - \#define LV_USE_SJPG 0
     - \#define LV_USE_GIF 0
     - \#define LV_USE_BARCODE 0

lv_conf_template.h

@@ -619,6 +619,9 @@
 /*Decode bin images to RAM*/
 #define LV_BIN_DECODER_RAM_LOAD 0
 
+/*RLE decoder library*/
+#define LV_USE_RLE 0
+
 /*QR code library*/
 #define LV_USE_QRCODE 0
 

lvgl.h

@@ -91,6 +91,7 @@ extern "C" {
 
 #include "src/libs/barcode/lv_barcode.h"
 #include "src/libs/bmp/lv_bmp.h"
+#include "src/libs/rle/lv_rle_decoder.h"
 #include "src/libs/fsdrv/lv_fsdrv.h"
 #include "src/libs/lodepng/lv_lodepng.h"
 #include "src/libs/libpng/lv_libpng.h"

src/libs/rle/lv_rle_decoder.c

@@ -0,0 +1,523 @@
+/**
+ * @file lv_rle_decoder.c
+ * Decode RLE compressed original lvgl binary file. File name suffix is always
+ * set to '.rle' and the file header is added with another 64bit including
+ * 32bit magic number and 32bit rle information.
+ *
+ * Decoder support both variable and file as image source.
+ *
+ * The original binary data is directly decompressed to ram, and decoded by
+ * lvgl built-in decoder.
+ */
+
+/*********************
+ *      INCLUDES
+ *********************/
+#include <stdlib.h>
+#include "lv_rle_decoder.h"
+
+#if LV_USE_RLE
+
+/*********************
+ *      DEFINES
+ *********************/
+
+#define RLE_HEADER_MAGIC        0x5aa521e0
+#define RLE_DECODER_OPTIMIZE_FS 1 /* load file to RAM to decode. */
+#define RLE_DECODER_PERF        0 /* output file load decoder performance */
+
+/**********************
+ *      TYPEDEFS
+ **********************/
+
+typedef struct {
+    lv_image_decoder_dsc_t decoder_dsc;
+    lv_image_dsc_t img_dsc;
+} lv_rle_decoder_data_t;
+
+typedef struct {
+    uint32_t magic;         /* 0x5aa521e0 */
+    uint32_t blksize: 4;    /* block size, the encoded data unit bytes. */
+    uint32_t len_orig: 24;  /* Original data length. */
+    uint32_t reserved: 4;
+} lv_rle_header_t;
+
+typedef struct {
+    lv_rle_header_t rleheader;
+    lv_image_header_t header;
+} lv_rle_file_header_t;
+
+/**********************
+ *  STATIC PROTOTYPES
+ **********************/
+static lv_res_t decoder_info(struct _lv_image_decoder_t * decoder,
+                             const void * src, lv_image_header_t * header);
+static lv_res_t decoder_open(lv_image_decoder_t * dec,
+                             lv_image_decoder_dsc_t * dsc);
+static void decoder_close(lv_image_decoder_t * dec, lv_image_decoder_dsc_t * dsc);
+
+/**********************
+ *  STATIC VARIABLES
+ **********************/
+
+/**********************
+ *      MACROS
+ **********************/
+
+/**********************
+ *   GLOBAL FUNCTIONS
+ **********************/
+
+void lv_rle_decoder_init(void)
+{
+    lv_image_decoder_t * dec = lv_image_decoder_create();
+    lv_image_decoder_set_info_cb(dec, decoder_info);
+    lv_image_decoder_set_open_cb(dec, decoder_open);
+    lv_image_decoder_set_close_cb(dec, decoder_close);
+}
+
+/**********************
+ *   STATIC FUNCTIONS
+ **********************/
+
+#if RLE_DECODER_OPTIMIZE_FS == 0
+static int rle_decompress_from_file(lv_fs_file_t * f, uint8_t * output,
+                                    uint32_t len, uint32_t blk_size)
+{
+    uint8_t ctrl_byte;
+    uint32_t wr_len = 0;
+    lv_fs_res_t res;
+
+    while(1) {
+        uint32_t rd;
+        res = lv_fs_read(f, &ctrl_byte, 1, &rd);
+        if(res != LV_FS_RES_OK) {
+            return 0;
+        }
+
+        if(rd == 0)
+            break;
+
+        if(ctrl_byte & 0x80) {
+            /* copy directly from input to output */
+            uint32_t bytes = blk_size * (ctrl_byte & 0x7f);
+
+            wr_len += bytes;
+            if(wr_len > len)
+                return 0;
+
+            res = lv_fs_read(f, output, bytes, &rd);
+            if(rd != bytes || res != LV_FS_RES_OK) {
+                return 0;
+            }
+            output += bytes;
+        }
+        else {
+            wr_len += blk_size * ctrl_byte;
+            if(wr_len > len)
+                return 0;
+
+            uint8_t input[blk_size];
+            res = lv_fs_read(f, input, blk_size, &rd);
+            if(rd != blk_size || res != LV_FS_RES_OK) {
+                return 0;
+            }
+
+            if(blk_size == 1) {
+                /* optimize the most common case. */
+                memset(output, input[0], ctrl_byte);
+                output += ctrl_byte;
+            }
+            else {
+                for(int i = 0; i < ctrl_byte; i++) {
+                    memcpy(output, input, blk_size);
+                    output += blk_size;
+                }
+            }
+
+        }
+    }
+
+    return wr_len;
+}
+#endif
+
+static int rle_decompress_from_mem(const uint8_t * input,
+                                   uint32_t input_buff_len, uint8_t * output,
+                                   uint32_t output_buff_len, uint8_t blk_size)
+{
+    uint32_t ctrl_byte;
+    uint32_t rd_len = 0;
+    uint32_t wr_len = 0;
+
+    while(rd_len < input_buff_len) {
+        ctrl_byte = input[0];
+        rd_len++;
+        input++;
+        if(rd_len > input_buff_len)
+            return 0;
+
+        if(ctrl_byte & 0x80) {
+            /* copy directly from input to output */
+            uint32_t bytes = blk_size * (ctrl_byte & 0x7f);
+            rd_len += bytes;
+            if(rd_len > input_buff_len)
+                return 0;
+
+            wr_len += bytes;
+            if(wr_len > output_buff_len)
+                return 0;
+
+            memcpy(output, input, bytes);
+            output += bytes;
+            input += bytes;
+        }
+        else {
+            rd_len += blk_size;
+            if(rd_len > input_buff_len)
+                return 0;
+
+            wr_len += blk_size * ctrl_byte;
+            if(wr_len > output_buff_len)
+                return 0;
+
+            if(blk_size == 1) {
+                /* optimize the most common case. */
+                memset(output, input[0], ctrl_byte);
+                output += ctrl_byte;
+            }
+            else {
+                for(uint32_t i = 0; i < ctrl_byte; i++) {
+                    memcpy(output, input, blk_size);
+                    output += blk_size;
+                }
+            }
+            input += blk_size;
+        }
+    }
+
+    return wr_len;
+}
+
+static lv_res_t decoder_info(struct _lv_image_decoder_t * decoder,
+                             const void * src, lv_image_header_t * header)
+{
+    (void) decoder; /*Unused*/
+    lv_image_src_t src_type = lv_image_src_get_type(src);   /*Get the source type*/
+
+    if(src_type == LV_IMAGE_SRC_FILE) {
+        lv_fs_res_t res;
+        uint32_t rn;
+        lv_fs_file_t f;
+        lv_rle_file_header_t file_header = { 0 };
+        /*Support only "*.rle" files*/
+        if(strcmp(lv_fs_get_ext(src), "rle") != 0)
+            return LV_RES_INV;
+
+        res = lv_fs_open(&f, src, LV_FS_MODE_RD);
+        if(res != LV_FS_RES_OK)
+            return LV_RES_INV;
+
+        res = lv_fs_read(&f, &file_header, sizeof(lv_rle_file_header_t), &rn);
+        lv_fs_close(&f);
+
+        if((res != LV_FS_RES_OK) || (rn != sizeof(lv_rle_file_header_t))) {
+            LV_LOG_WARN("Image get info get read file header");
+            return LV_RES_INV;
+        }
+
+        if(file_header.rleheader.magic != RLE_HEADER_MAGIC) {
+            return LV_RES_INV;
+        }
+
+        *header = file_header.header;
+
+        return LV_RES_OK;
+    }
+    else if(src_type == LV_IMAGE_SRC_VARIABLE) {
+        const lv_image_dsc_t * img_dsc = src;
+        const lv_rle_header_t * rleheader = (const lv_rle_header_t *)img_dsc->data;
+        if(rleheader->magic != RLE_HEADER_MAGIC) {
+            return LV_RES_INV;
+        }
+
+        header->always_zero = 0;
+        header->cf = img_dsc->header.cf;
+        header->w = img_dsc->header.w;
+        header->h = img_dsc->header.h;
+
+        return LV_RES_OK;
+    }
+
+    return LV_RES_INV;
+}
+
+static inline lv_res_t decode_from_file(lv_image_decoder_t * decoder,
+                                        lv_image_decoder_dsc_t * dsc,
+                                        lv_rle_file_header_t * fileheader,
+                                        void ** img_data)
+{
+    LV_UNUSED(decoder);
+    lv_fs_res_t res;
+    lv_fs_file_t f;
+    uint32_t rd_cnt;
+    uint32_t px_size;
+    void * img_buf;
+    uint32_t buf_len;
+    uint32_t decoded_len;
+    lv_image_header_t * header = &fileheader->header;
+    lv_rle_header_t * rleheader = &fileheader->rleheader;
+    const char * fn = dsc->src;
+
+    res = lv_fs_open(&f, fn, LV_FS_MODE_RD);
+    if(res != LV_FS_RES_OK) {
+        LV_LOG_WARN("RLE image decoder can't open the file");
+        return LV_RES_INV;
+    }
+
+    res = lv_fs_read(&f, fileheader, sizeof(lv_rle_file_header_t), &rd_cnt);
+    if(rleheader->magic != RLE_HEADER_MAGIC) {
+        return LV_RES_INV;
+    }
+
+    if((res != LV_FS_RES_OK) || (rd_cnt != sizeof(lv_rle_file_header_t))) {
+        LV_LOG_WARN("RLE image decoder read header failed.");
+        goto error_file;
+    }
+
+    px_size = lv_color_format_get_size(header->cf);
+    if(px_size == 0) {
+        goto error_file;
+    }
+
+    if(px_size != rleheader->blksize) {
+        LV_LOG_WARN("Invalid rle file, blksize mismatch, expect: %" LV_PRIu32", got %d", px_size, rleheader->blksize);
+        goto error_file;
+    }
+
+    buf_len = rleheader->len_orig;
+    if(buf_len == 0) {
+        LV_LOG_WARN("Invalid rle file, len_orig %d", rleheader->len_orig);
+        goto error_file;
+    }
+
+    img_buf = lv_draw_buf_malloc(buf_len, header->cf);
+    if(img_buf == NULL) {
+        LV_LOG_ERROR("alloc img buf failed: %" LV_PRId32, buf_len);
+        goto error_file;
+    }
+
+#if RLE_DECODER_OPTIMIZE_FS
+    uint32_t size = 0;
+    if(lv_fs_seek(&f, 0, LV_FS_SEEK_END) != 0) {
+        goto error_with_img_buf;
+    }
+
+    lv_fs_tell(&f, &size);
+    size -= sizeof(lv_rle_file_header_t);
+
+    if(lv_fs_seek(&f, sizeof(lv_rle_file_header_t), LV_FS_SEEK_SET) != 0) {
+        goto error_with_img_buf;
+    }
+
+    void * file_buffer = lv_malloc(size);
+    if(file_buffer == NULL) {
+        goto error_with_img_buf;
+    }
+
+#if RLE_DECODER_PERF
+    int start, read_cost, decompress_cost;
+
+    start = lv_tick_get();
+#endif
+
+    res = lv_fs_read(&f, file_buffer, size, &rd_cnt);
+    if(res != LV_RES_INV || rd_cnt != size) {
+        lv_free(file_buffer);
+        goto error_with_img_buf;
+    }
+
+    lv_fs_close(&f);
+
+#if RLE_DECODER_PERF
+    read_cost = lv_tick_elaps(start);
+    start = lv_tick_get();
+#endif
+
+    decoded_len = rle_decompress_from_mem(file_buffer, size, img_buf, buf_len,
+                                          rleheader->blksize);
+
+#if RLE_DECODER_PERF
+    decompress_cost = lv_tick_elaps(start);
+    LV_LOG_USER("file size: %" LV_PRIu32 ", img size: %" LV_PRIu32 ", readtime: %d, decode: %d\n",
+                size, buf_len, read_cost, decompress_cost);
+#endif
+
+    lv_free(file_buffer);
+
+    if(decoded_len != buf_len) {
+        LV_LOG_WARN("rle decode failed, decoded len: %" LV_PRIu32
+                    ", expected %" LV_PRIu32 ".",
+                    decoded_len, buf_len);
+        lv_free(img_buf);
+        return LV_RES_INV;
+    }
+#else
+    /**
+     * Read and decompress data.
+     */
+    decoded_len = rle_decompress_from_file(&f, img_buf, buf_len,
+                                           rleheader->blksize);
+
+    lv_fs_close(&f);
+    if(decoded_len != buf_len) {
+        LV_LOG_WARN("rle decode failed, decoded len: %d, expect %d.",
+                    decoded_len, buf_len);
+        lv_free(img_buf);
+        return LV_RES_INV;
+    }
+#endif
+
+    *img_data = img_buf;
+    return LV_RES_OK;
+
+#if RLE_DECODER_OPTIMIZE_FS
+error_with_img_buf:
+    lv_free(img_buf);
+#endif
+
+error_file:
+    lv_fs_close(&f);
+    return LV_RES_INV;
+}
+
+static inline lv_res_t decode_from_variable(lv_image_decoder_t * decoder,
+                                            lv_image_decoder_dsc_t * dsc,
+                                            lv_rle_file_header_t * fileheader,
+                                            void ** img_data)
+{
+    LV_UNUSED(decoder);
+    uint32_t px_size;
+    void * img_buf;
+    uint32_t buf_len;
+    uint32_t decoded_len;
+    const lv_image_dsc_t * img_dsc = dsc->src;
+    const lv_rle_header_t * rleheader = (const lv_rle_header_t *)img_dsc->data;
+    const lv_image_header_t * header = &img_dsc->header;
+
+    if(rleheader->magic != RLE_HEADER_MAGIC) {
+        return LV_RES_INV;
+    }
+
+    px_size = lv_color_format_get_size(header->cf);
+    if(px_size == 0) {
+        return LV_RES_INV;
+    }
+
+    if(px_size != rleheader->blksize) {
+        LV_LOG_WARN("Invalid rle file, blksize mismatch, expect: %" LV_PRIu32
+                    ", got %d",
+                    px_size, rleheader->blksize);
+        return LV_RES_INV;
+    }
+
+    buf_len = rleheader->len_orig;
+    if(buf_len == 0) {
+        LV_LOG_WARN("Invalid rle file, len_orig %d", rleheader->len_orig);
+        return LV_RES_INV;
+    }
+
+    img_buf = lv_malloc(buf_len);
+    if(img_buf == NULL) {
+        return LV_RES_INV;
+    }
+
+    const uint8_t * compressed_data = img_dsc->data + sizeof(lv_rle_header_t);
+    uint32_t compressed_data_len = img_dsc->data_size - sizeof(lv_rle_header_t);
+
+    decoded_len = rle_decompress_from_mem(compressed_data, compressed_data_len,
+                                          img_buf, buf_len, rleheader->blksize);
+
+    if(decoded_len != buf_len) {
+        LV_LOG_WARN("rle decode failed, decoded len: %" LV_PRIu32
+                    ", expected %" LV_PRIu32 ".",
+                    decoded_len, buf_len);
+        lv_free(img_buf);
+        return LV_RES_INV;
+    }
+
+    fileheader->header = *header;
+    fileheader->rleheader = *rleheader;
+    *img_data = img_buf;
+    return LV_RES_OK;
+}
+
+static lv_res_t decoder_open(lv_image_decoder_t * decoder,
+                             lv_image_decoder_dsc_t * dsc)
+{
+    lv_fs_res_t res;
+    lv_rle_file_header_t fileheader;
+    lv_rle_decoder_data_t * data;
+    void * img_data;
+    if(dsc->src_type == LV_IMAGE_SRC_FILE) {
+        res = decode_from_file(decoder, dsc, &fileheader, &img_data);
+        if(res != LV_RES_OK)
+            return res;
+    }
+
+    else if(dsc->src_type == LV_IMAGE_SRC_VARIABLE) {
+        res = decode_from_variable(decoder, dsc, &fileheader, &img_data);
+
+        if(res != LV_RES_OK)
+            return res;
+    }
+    else {
+        return LV_RES_INV;
+    }
+
+    /*Decoder private data.*/
+    data = lv_malloc(sizeof(*data));
+    if(data == NULL) {
+        return LV_RES_INV;
+    }
+
+    lv_memcpy(&data->decoder_dsc, dsc, sizeof(*dsc));
+
+    data->img_dsc.header = fileheader.header;
+    data->img_dsc.data = img_data;
+    data->img_dsc.data_size = fileheader.rleheader.len_orig;
+
+    data->decoder_dsc.img_data = NULL;
+    data->decoder_dsc.src_type = LV_IMAGE_SRC_VARIABLE;
+    data->decoder_dsc.src = &data->img_dsc;
+
+    res = lv_image_decoder_built_in_open(decoder, &data->decoder_dsc);
+    if(res != LV_RES_OK) {
+        lv_free(img_data);
+        lv_free(data);
+        return LV_RES_INV;
+    }
+
+    dsc->img_data = data->decoder_dsc.img_data;
+    dsc->header = data->decoder_dsc.header;
+    dsc->user_data = data;
+    return LV_RES_OK;
+}
+
+static void decoder_close(lv_image_decoder_t * decoder, lv_image_decoder_dsc_t * dsc)
+{
+    if(dsc->user_data) {
+        lv_rle_decoder_data_t * decoder_data = dsc->user_data;
+        lv_image_decoder_built_in_close(decoder, &decoder_data->decoder_dsc);
+        if(decoder_data->img_dsc.data)
+            lv_free((void *)decoder_data->img_dsc.data);
+        lv_free(dsc->user_data);
+        dsc->user_data = NULL;
+    }
+
+    if(dsc->img_data) {
+        dsc->img_data = NULL;
+    }
+}
+
+#endif /*LV_USE_RLE*/

src/libs/rle/lv_rle_decoder.h

@@ -0,0 +1,47 @@
+/**
+ * @file lv_rle_decoder.h
+ *
+ */
+
+#ifndef LV_RLE_DECODER_H
+#define LV_RLE_DECODER_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*********************
+ *      INCLUDES
+ *********************/
+#include "../../../lvgl.h"
+
+#if LV_USE_RLE
+
+/*********************
+ *      DEFINES
+ *********************/
+
+/**********************
+ *      TYPEDEFS
+ **********************/
+
+/**********************
+ * GLOBAL PROTOTYPES
+ **********************/
+
+/**
+ * Register the RLE decoder functions in LVGL
+ */
+void lv_rle_decoder_init(void);
+
+/**********************
+ *      MACROS
+ **********************/
+
+#endif /*LV_USE_RLE*/
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /*LV_RLE_DECODER_H*/

src/lv_conf_internal.h

@@ -2055,6 +2055,15 @@
     #endif
 #endif
 
+/*RLE decoder library*/
+#ifndef LV_USE_RLE
+    #ifdef CONFIG_LV_USE_RLE
+        #define LV_USE_RLE CONFIG_LV_USE_RLE
+    #else
+        #define LV_USE_RLE 0
+    #endif
+#endif
+
 /*QR code library*/
 #ifndef LV_USE_QRCODE
     #ifdef CONFIG_LV_USE_QRCODE

src/lv_init.c

@@ -258,6 +258,10 @@ void lv_init(void)
     lv_bmp_init();
 #endif
 
+#if LV_USE_RLE
+    lv_rle_decoder_init();
+#endif
+
     /*Make FFMPEG last because the last converter will be checked first and
      *it's superior to any other */
 #if LV_USE_FFMPEG

tests/src/lv_test_conf_full.h

@@ -60,6 +60,7 @@
 #define LV_USE_FS_MEMFS     1
 #define LV_FS_MEMFS_LETTER  'M'
 
+#define LV_USE_RLE          1
 #define LV_USE_LODEPNG      1
 #define LV_USE_LIBPNG       1
 #define LV_USE_BMP          1

tests/src/lv_test_conf_minimal.h

@@ -17,5 +17,6 @@
 
 #define  LV_USE_LODEPNG                 1
 #define  LV_USE_BMP                     1
+#define  LV_USE_RLE                     1
 #define  LV_USE_GIF                     1
 #define  LV_USE_QRCODE                  1

tests/src/test_cases/draw/test_image_formats.c

@@ -157,4 +157,52 @@ void test_image_built_in_decode_rotate_and_recolor(void)
     TEST_ASSERT_EQUAL_SCREENSHOT("draw/image_format_rotate_and_recolor.png");
 }
 
+void test_image_rle_decode(void)
+{
+    img_create("rleA8", "A:src/test_files/binimages/cogwheel.A8.rle", false, false);
+    img_create("rleI1", "A:src/test_files/binimages/cogwheel.I1.rle", false, false);
+    img_create("rleI2", "A:src/test_files/binimages/cogwheel.I2.rle", false, false);
+    img_create("rleI4", "A:src/test_files/binimages/cogwheel.I4.rle", false, false);
+    img_create("rleI8", "A:src/test_files/binimages/cogwheel.I8.rle", false, false);
+    img_create("rleRGB565A8", "A:src/test_files/binimages/cogwheel.RGB565A8.rle", false, false);
+    img_create("rleRGB565", "A:src/test_files/binimages/cogwheel.RGB565.rle", false, false);
+    img_create("rleRGB888", "A:src/test_files/binimages/cogwheel.RGB888.rle", false, false);
+    img_create("rleXRGB8888", "A:src/test_files/binimages/cogwheel.XRGB8888.rle", false, false);
+    img_create("rleARGB8888", "A:src/test_files/binimages/cogwheel.ARGB8888.rle", false, false);
+
+    TEST_ASSERT_EQUAL_SCREENSHOT("draw/image_format_rle.png");
+}
+
+void test_image_rle_decode_rotate(void)
+{
+    img_create("rleA8", "A:src/test_files/binimages/cogwheel.A8.rle", true, false);
+    img_create("rleI1", "A:src/test_files/binimages/cogwheel.I1.rle", true, false);
+    img_create("rleI2", "A:src/test_files/binimages/cogwheel.I2.rle", true, false);
+    img_create("rleI4", "A:src/test_files/binimages/cogwheel.I4.rle", true, false);
+    img_create("rleI8", "A:src/test_files/binimages/cogwheel.I8.rle", true, false);
+    img_create("rleRGB565A8", "A:src/test_files/binimages/cogwheel.RGB565A8.rle", true, false);
+    img_create("rleRGB565", "A:src/test_files/binimages/cogwheel.RGB565.rle", true, false);
+    img_create("rleRGB888", "A:src/test_files/binimages/cogwheel.RGB888.rle", true, false);
+    img_create("rleXRGB8888", "A:src/test_files/binimages/cogwheel.XRGB8888.rle", true, false);
+    img_create("rleARGB8888", "A:src/test_files/binimages/cogwheel.ARGB8888.rle", true, false);
+
+    TEST_ASSERT_EQUAL_SCREENSHOT("draw/image_format_rle_rotate.png");
+}
+
+void test_image_rle_decode_rotate_recolor(void)
+{
+    img_create("rleA8", "A:src/test_files/binimages/cogwheel.A8.rle", true, true);
+    img_create("rleI1", "A:src/test_files/binimages/cogwheel.I1.rle", true, true);
+    img_create("rleI2", "A:src/test_files/binimages/cogwheel.I2.rle", true, true);
+    img_create("rleI4", "A:src/test_files/binimages/cogwheel.I4.rle", true, true);
+    img_create("rleI8", "A:src/test_files/binimages/cogwheel.I8.rle", true, true);
+    img_create("rleRGB565A8", "A:src/test_files/binimages/cogwheel.RGB565A8.rle", true, true);
+    img_create("rleRGB565", "A:src/test_files/binimages/cogwheel.RGB565.rle", true, true);
+    img_create("rleRGB888", "A:src/test_files/binimages/cogwheel.RGB888.rle", true, true);
+    img_create("rleXRGB8888", "A:src/test_files/binimages/cogwheel.XRGB8888.rle", true, true);
+    img_create("rleARGB8888", "A:src/test_files/binimages/cogwheel.ARGB8888.rle", true, true);
+
+    TEST_ASSERT_EQUAL_SCREENSHOT("draw/image_format_rle_rotate_recolor.png");
+}
+
 #endif