klips/esp/cpp/components/lcd/panel_device.cpp

/*#############################################################################
## Author: Shaun Reed                                                        ##
## Legal: All Content (c) 2025 Shaun Reed, all rights reserved               ##
##                                                                           ##
## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com                     ##
##############################################################################
*/
#include "include/panel_device.h"

#include <esp_timer.h>
#include <lcd.h>
#include <sys/unistd.h>

static bool lvgl_flush_ready_cb(esp_lcd_panel_io_handle_t,
                                esp_lcd_panel_io_event_data_t*, void* user_ctx)
{
    auto* disp = (lv_display_t*)user_ctx;
    lv_display_flush_ready(disp);
    return false;
}

static void lvgl_flush_cb(lv_display_t* display, const lv_area_t* area,
                          uint8_t* px_map) // NOLINT(*-non-const-parameter)
{
    auto panel_handle =
        (esp_lcd_panel_handle_t)lv_display_get_user_data(display);

    // Necessary because LVGL reserves 2x4 bytes in the buffer for a palette.
    // Since we are monochrome, we don't need these additional bytes.
    // For more information about the monochrome, please refer to:
    // https://docs.lvgl.io/9.2/porting/display.html#monochrome-displays
    // Skip the palette here.
    px_map += LVGL_PALETTE_SIZE;

    uint16_t hor_res = lv_display_get_physical_horizontal_resolution(display);
    int32_t x1 = area->x1;
    int32_t x2 = area->x2;
    int32_t y1 = area->y1;
    int32_t y2 = area->y2;


    // As of 03/01/2025 master branch of LVGL contains this helper for the same.
    // https://docs.lvgl.io/master/API/draw/sw/lv_draw_sw_utils.html
    // lv_draw_sw_i1_convert_to_vtiled()
    for (int32_t y = y1; y <= y2; y++)
    {
        for (int32_t x = x1; x <= x2; x++)
        {
            // Get the byte offset of the pixel coordinates using
            // horizontal-mapping.
            int h_offset = horizontal_byte_offset_long(x, y, hor_res);
            // True if the pixel is lit, else false.
            bool chroma_color = px_map[h_offset] & msb_mask(x);

            // We need an additional buffer for transposing the pixel data to
            // the vertical format required by the display driver.
            uint8_t* buf = get_additional_draw_buffer();
            // Move to the position in the auxillary buffer where the pixel is
            // stored.
            buf += vertical_byte_offset_long(x, y, hor_res);

            // Write the single bit to the monochrome display mapped vertically.
            // Take the Least Significant Bit mask of the Y coordinate to select
            // the bit representing a pixel at position y in a vertically-mapped
            // display.
            if (chroma_color)
            {
                // Set the vertically-mapped pixel to on.
                *buf &= ~lsb_mask(y);
            }
            else
            {
                // Set the vertically-mapped pixel to off.
                *buf |= lsb_mask(y);
            }
        }
    }
    // Pass the draw buffer to the driver.
    ESP_ERROR_CHECK(esp_lcd_panel_draw_bitmap(
        panel_handle, x1, y1, x2 + 1, y2 + 1, get_additional_draw_buffer()));
}

static void lvgl_increase_tick_cb(void*)
{
    // Tell LVGL how many milliseconds has elapsed
    lv_tick_inc(LVGL_TICK_PERIOD_MS);
}

[[noreturn]] static void lvgl_port_task(void*)
{
    // Optionally initialize some LVGL objects here before entering loop below.

    ESP_LOGI(LCD_TAG, "Starting LVGL task");
    for (uint32_t time_to_next_ms = 0; true; usleep(1000 * time_to_next_ms))
    {
        // Obtain LVGL API lock before calling any LVGL methods.
        _lock_acquire(&lv_lock_);

        // Optionally handle LVGL input or event logic here.

        // Update LVGL periodic timers.
        time_to_next_ms = lv_timer_handler();

        _lock_release(&lv_lock_);
    }
}

void register_rendering_data(lv_display_t* display_handle,
                             esp_lcd_panel_io_handle_t io_handle, void* lv_buf,
                             size_t lv_buf_size)
{
    // Create draw buffer.
    ESP_LOGI(LCD_TAG, "Allocate separate LVGL draw buffers");
    lv_buf =
        heap_caps_calloc(1, lv_buf_size, MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
    assert(lv_buf);

    ESP_LOGI(LCD_TAG, "Set LVGL draw buffers");
    // Color format must be set first, LVGL9 support new monochromatic format.
    lv_display_set_color_format(display_handle, LV_COLOR_FORMAT_I1);
    lv_display_set_buffers(display_handle, lv_buf, nullptr, lv_buf_size,
                           LV_DISPLAY_RENDER_MODE_FULL);
    lv_display_set_rotation(display_handle, LV_DISPLAY_ROTATION_0);

    ESP_LOGI(LCD_TAG, "Set LVGL callback for flushing to the display");
    lv_display_set_flush_cb(display_handle, lvgl_flush_cb);

    ESP_LOGI(LCD_TAG,
             "Register io panel callback for LVGL flush ready notification");
    const esp_lcd_panel_io_callbacks_t cbs = {
        .on_color_trans_done = lvgl_flush_ready_cb,
    };
    ESP_ERROR_CHECK(esp_lcd_panel_io_register_event_callbacks(io_handle, &cbs,
                                                              display_handle));
}

/**
 * Registers LVGL ticker timer callback for rendering this display.
 *
 * An implementation of the interface can optionally override this method to
 * provide custom LVGL callbacks and tick configurations.
 */
void register_lvgl_tick_timer()
{
    ESP_LOGI(LCD_TAG, "Use esp_timer to increase LVGL tick");
    const esp_timer_create_args_t esp_timer_args = {
        .callback = &lvgl_increase_tick_cb,
        // Data to pass to the lvgl_port_task callback.
        .arg = nullptr,
        .name = "lvgl_tick",
    };

    /// Start periodic ESP timer handle.
    esp_timer_handle_t esp_timer_;
    ESP_LOGI(LCD_TAG, "Creating esp_timer with name: '%s'",
             esp_timer_args.name);
    ESP_ERROR_CHECK(esp_timer_create(&esp_timer_args, &esp_timer_));
    ESP_ERROR_CHECK(
        esp_timer_start_periodic(esp_timer_, LVGL_TICK_PERIOD_MS * 1000));
    ESP_LOGI(LCD_TAG, "Starting esp_timer with name: '%s'",
             esp_timer_args.name);

    // LVGL requires a FreeRTOS task for running it's event loop.
    // The lvgl_port_task callback can update the UI or handle input logic.
    // For this basic example we don't do either of these things.
    ESP_LOGI(LCD_TAG, "Create LVGL FreeRTOS task");
    // Optionally set user data to pass to LVGL's FreeRTOS task callback here.
    void* user_data = nullptr;
    xTaskCreate(lvgl_port_task, "LVGL", LVGL_TASK_STACK_SIZE, user_data,
                LVGL_TASK_PRIORITY, nullptr);
}