Prepare image for use with LVGL

[karunt]

Question about an existing feature

What are you trying to achieve?

Using ESP32-S3 with RGB565 LCD to display image. Currently, image is converted to raw buffer format in node.js server and then sent to ESP32-S3 over http. But when ESP32-S3 tries to display image using LVGL, the program core dumps and reboots. Can't figure our why that's happening. Relevant code shown below.

When you searched for similar issues, what did you find that might be related?

Haven't found any discussion on this topic yet

Please provide a minimal, standalone code sample, without other dependencies, that demonstrates this question

Node.js code to modify image to .bin file:

try{
            await sharp(sourceFile)
            .extract({left: 0, top: 0, width: 100, height: 100})
            .resize(480, 480)
            .raw()
            .toBuffer()
            .then(data => fs.writeFileSync('cups01.bin', data));
} catch(err) {console.log('error after saving file: ', err)}

ESP code to retrieve converted image into buffer for display by LVGL:

void display_img(uint8_t *img_buffer, int file_size){

    lv_obj_t *img1 = lv_img_create(lv_scr_act());
    lv_img_dsc_t newImg = {
        .header.always_zero = 0,
        .header.w =480,
        .header.h =480,
        .data_size = file_size,
        .header.cf = LV_IMG_CF_TRUE_COLOR,
        .data = (const uint8_t *)img_buffer
    };
    lv_img_set_src(img1, &newImg);
    
    if (lvgl_port_lock(-1)) {
        lvgl_port_unlock();
    }
}

void http_get(char *file){
    
    int cum_data_read = 0;
    int i = 1;
    int resp_length;
    char *output_buffer = (char *)calloc(sizeof(char), MAX_HTTP_OUTPUT_BUFFER);
    char uri[256];
    snprintf(uri, sizeof(uri), "%s://%s:%s/esp?file=%s", httpServer, httpIpAddress, httpPort, file);
    esp_http_client_config_t config = {
        .url = uri
    };
    esp_http_client_handle_t client = esp_http_client_init(&config);
    esp_http_client_set_method(client, HTTP_METHOD_GET);
    esp_err_t err = esp_http_client_open(client, 0);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Failed to open HTTP connection: %s", esp_err_to_name(err));
    } else {
        int content_length = esp_http_client_fetch_headers(client);
        uint8_t *image_buffer = (uint8_t *)calloc(content_length, sizeof(uint8_t));

            do {
                resp_length = esp_http_client_read_response(client, output_buffer, MAX_HTTP_OUTPUT_BUFFER);
                if (resp_length >= 0) {
                    memcpy(image_buffer + cum_data_read, output_buffer, resp_length);
                    cum_data_read += resp_length;
                } else {
                    ESP_LOGE(TAG, "Failed to read response");
                }
                i++;
            }
            while (cum_data_read < content_length);

            display_img(image_buffer, cum_data_read);
        }
    }
    esp_http_client_close(client);
}   

Please provide sample image(s) that help explain this question

Can't upload .bin file

[lovell]

This might be an alpha channel problem (RGB vs RGBA). Perhaps try adding ensureAlpha or removeAlpha depending on your need.