Lv_color_format_rgb565a8

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1

Hi everyone,

I’m using LVGL v9.2 with an ESP32-S3 and an RGB LCD display via the esp_lcd_rgb_panel driver. My color format is set to LV_COLOR_FORMAT_RGB565A8 because I want to enable alpha transparency for blending.

However, transparency is not working as expected.

Can anyone help me figure out what might be missing or misconfigured?

Thanks in advance!

2

Seems you missunderstand somethink Color Format — LVGL 9.3 documentation

this latest , but older too dont have A8 framebuffers…

3

i can show you my code :

static bool example_notify_lvgl_flush_ready(esp_lcd_panel_handle_t panel, const esp_lcd_rgb_panel_event_data_t *event_data, void *user_ctx)
{
lv_display_t *disp = (lv_display_t *)user_ctx;
lv_display_flush_ready(disp);
return false;
}

static void example_lvgl_flush_cb(lv_display_t *disp, const lv_area_t *area, uint8_t *px_map)
{
esp_lcd_panel_handle_t panel_handle = lv_display_get_user_data(disp);
int offsetx1 = area->x1;
int offsetx2 = area->x2;
int offsety1 = area->y1;
int offsety2 = area->y2;
// pass the draw buffer to the driver
esp_lcd_panel_draw_bitmap(panel_handle, offsetx1, offsety1, offsetx2 + 1, offsety2 + 1, px_map);
lv_disp_flush_ready(disp);
}

static void example_increase_lvgl_tick(void arg)
{
/ Tell LVGL how many milliseconds has elapsed */
lv_tick_inc(EXAMPLE_LVGL_TICK_PERIOD_MS);
}

static void example_bsp_init_lcd_backlight(void)
{
gpio_config_t bk_gpio_config = {
.mode = GPIO_MODE_OUTPUT,
.pin_bit_mask = 1ULL << EXAMPLE_PIN_NUM_BK_LIGHT
};
ESP_ERROR_CHECK(gpio_config(&bk_gpio_config));
}

static void example_bsp_set_lcd_backlight(uint32_t level)
{
gpio_set_level(EXAMPLE_PIN_NUM_BK_LIGHT, level);
}

void task_lvgl_main(void *arg)
{

ESP_LOGI(TAG, "Turn off LCD backlight");
example_bsp_init_lcd_backlight();
example_bsp_set_lcd_backlight(EXAMPLE_LCD_BK_LIGHT_OFF_LEVEL);

ESP_LOGI(TAG, "Install RGB LCD panel driver");
esp_lcd_panel_handle_t panel_handle = NULL;
esp_lcd_rgb_panel_config_t panel_config = {
    .data_width = EXAMPLE_DATA_BUS_WIDTH,
    .psram_trans_align = 64,
    .num_fbs = EXAMPLE_LCD_NUM_FB,
    .clk_src = LCD_CLK_SRC_DEFAULT,
    .disp_gpio_num = EXAMPLE_PIN_NUM_DISP_EN,
    .pclk_gpio_num = EXAMPLE_PIN_NUM_PCLK,
    .vsync_gpio_num = EXAMPLE_PIN_NUM_VSYNC,
    .hsync_gpio_num = EXAMPLE_PIN_NUM_HSYNC,
    .de_gpio_num = EXAMPLE_PIN_NUM_DE,
    .data_gpio_nums = {
        EXAMPLE_PIN_NUM_DATA0,
        EXAMPLE_PIN_NUM_DATA1,
        EXAMPLE_PIN_NUM_DATA2,
        EXAMPLE_PIN_NUM_DATA3,
        EXAMPLE_PIN_NUM_DATA4,
        EXAMPLE_PIN_NUM_DATA5,
        EXAMPLE_PIN_NUM_DATA6,
        EXAMPLE_PIN_NUM_DATA7,
        EXAMPLE_PIN_NUM_DATA8,
        EXAMPLE_PIN_NUM_DATA9,
        EXAMPLE_PIN_NUM_DATA10,
        EXAMPLE_PIN_NUM_DATA11,
        EXAMPLE_PIN_NUM_DATA12,
        EXAMPLE_PIN_NUM_DATA13,
        EXAMPLE_PIN_NUM_DATA14,
        EXAMPLE_PIN_NUM_DATA15,
    },
    .timings = {
        .pclk_hz = EXAMPLE_LCD_PIXEL_CLOCK_HZ,
        .h_res = EXAMPLE_LCD_H_RES,
        .v_res = EXAMPLE_LCD_V_RES,
        .hsync_back_porch = EXAMPLE_LCD_HBP,
        .hsync_front_porch = EXAMPLE_LCD_HFP,
        .hsync_pulse_width = EXAMPLE_LCD_HSYNC,
        .vsync_back_porch = EXAMPLE_LCD_VBP,
        .vsync_front_porch = EXAMPLE_LCD_VFP,
        .vsync_pulse_width = EXAMPLE_LCD_VSYNC,
        .flags = {
            .pclk_active_neg = true,
        },
    },
    .flags.fb_in_psram = true, // allocate frame buffer in PSRAM
};
ESP_ERROR_CHECK(esp_lcd_new_rgb_panel(&panel_config, &panel_handle));

ESP_LOGI(TAG, "Initialize RGB LCD panel");
ESP_ERROR_CHECK(esp_lcd_panel_reset(panel_handle));
ESP_ERROR_CHECK(esp_lcd_panel_init(panel_handle));

ESP_LOGI(TAG, "Turn on LCD backlight");
example_bsp_set_lcd_backlight(EXAMPLE_LCD_BK_LIGHT_ON_LEVEL);

ESP_LOGI(TAG, "Initialize LVGL library");
lv_init();
// create a lvgl display
lv_display_t *display = lv_display_create(EXAMPLE_LCD_H_RES, EXAMPLE_LCD_V_RES);

/*touch_screen*/
/* Create and set up at least one display before you register any input devices. */
lv_indev_t * indev = lv_indev_create();        /* Create input device connected to Default Display. */
lv_indev_set_type(indev, LV_INDEV_TYPE_POINTER);   /* Touch pad is a pointer-like device. */
lv_indev_set_read_cb(indev, lv_ft3663g_read);    /* Set driver function. */
/*touch_screen*/

// associate the rgb panel handle to the display
lv_display_set_user_data(display, panel_handle);
// set color depth
lv_display_set_color_format(display, EXAMPLE_LV_COLOR_FORMAT);
// create draw buffers
void *buf1 = NULL;
void *buf2 = NULL;

ESP_LOGI(TAG, "Allocate LVGL draw buffers");
// it's recommended to allocate the draw buffer from internal memory, for better performance
size_t draw_buffer_sz = EXAMPLE_LCD_H_RES * EXAMPLE_LVGL_DRAW_BUF_LINES * EXAMPLE_PIXEL_SIZE;
//buf1 = heap_caps_malloc(draw_buffer_sz, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT); //origin
buf1 = heap_caps_malloc(draw_buffer_sz, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT ); 
assert(buf1);
buf2 = heap_caps_malloc(draw_buffer_sz, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT ); 
assert(buf2);
// set LVGL draw buffers and partial mode
lv_display_set_buffers(display, buf1, buf2, draw_buffer_sz, LV_DISPLAY_RENDER_MODE_PARTIAL);

// set the callback which can copy the rendered image to an area of the display
lv_display_set_flush_cb(display, example_lvgl_flush_cb);

ESP_LOGI(TAG, "Register event callbacks");
esp_lcd_rgb_panel_event_callbacks_t cbs = {
    .on_color_trans_done = example_notify_lvgl_flush_ready,
};
ESP_ERROR_CHECK(esp_lcd_rgb_panel_register_event_callbacks(panel_handle, &cbs, display));

ESP_LOGI(TAG, "Install LVGL tick timer");
// Tick interface for LVGL (using esp_timer to generate 2ms periodic event)
const esp_timer_create_args_t lvgl_tick_timer_args = {
    .callback = &example_increase_lvgl_tick,
    .name = "lvgl_tick"
};
esp_timer_handle_t lvgl_tick_timer = NULL;
ESP_ERROR_CHECK(esp_timer_create(&lvgl_tick_timer_args, &lvgl_tick_timer));
ESP_ERROR_CHECK(esp_timer_start_periodic(lvgl_tick_timer, EXAMPLE_LVGL_TICK_PERIOD_MS * 1000));
ESP_LOGI(TAG, "Display LVGL UI");
example();

while (1)
{
    // raise the task priority of LVGL and/or reduce the handler period can improve the performance
    vTaskDelay(pdMS_TO_TICKS(10));
    /* Try to take the semaphore, call lvgl related function on success */
    if (pdTRUE == xSemaphoreTake(xGuiSemaphore, portMAX_DELAY)) {
        //ESP_LOGI(TAG, "xGuiSemaphore take OK");
        lv_task_handler();
        xSemaphoreGive(xGuiSemaphore);
    }
}

}

4

and what?

5

as i know we can use the image decoder with LV_COLOR_FORMAT_RGB565A8 !! im using lvgl 9.2.0

6

Images yes , framebuffer no

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