ESP LCD Panel API example

// change below to your settings
// screen dimensions
#define LCD_WIDTH 320
#define LCD_HEIGHT 240
// screen connections
#define LCD_CLK 18
#define LCD_MOSI 23
#define LCD_DC 2
#define LCD_CS 15
#define LCD_RST 4
#define LCD_BL 32 // optional

#include "driver/gpio.h"
#include "driver/spi_master.h"
#include "esp_lcd_panel_io.h"
#include "esp_lcd_panel_ops.h"
#include "esp_lcd_panel_vendor.h"
// include your custom panel driver here
...
// the size of our transfer buffer(s)
static const constexpr size_t lcd_transfer_buffer_size = LCD_WIDTH*LCD_HEIGHT*2/10;
static uint8_t* lcd_transfer_buffer1 = nullptr;
// the second buffer
static uint8_t* lcd_transfer_buffer2 = nullptr;
...
// initialize the screen using the esp panel API
static void lcd_init() {
#ifdef LCD_BL
#if LCD_BL > -1
    gpio_set_direction((gpio_num_t)LCD_BL,GPIO_MODE_OUTPUT);
    gpio_set_level((gpio_num_t)LCD_BL,0);
#endif
#endif
    lcd_transfer_buffer1 = (uint8_t*)heap_caps_malloc(lcd_transfer_buffer_size,MALLOC_CAP_DMA);
#ifdef TWO_BUFFERS
    lcd_transfer_buffer2 = (uint8_t*)heap_caps_malloc(lcd_transfer_buffer_size,MALLOC_CAP_DMA);
#endif
    if(lcd_transfer_buffer1==nullptr
#ifdef TWO_BUFFERS
        ||lcd_transfer_buffer2==nullptr
#endif
    ) {
        puts("Out of memory allocating transfer buffer");
        while(1) vTaskDelay(5);
    }
    spi_bus_config_t buscfg;
    memset(&buscfg, 0, sizeof(buscfg));
    buscfg.sclk_io_num = LCD_CLK;
    buscfg.mosi_io_num = LCD_MOSI;
    buscfg.miso_io_num = -1;
    buscfg.quadwp_io_num = -1;
    buscfg.quadhd_io_num = -1;
    buscfg.max_transfer_sz = lcd_transfer_buffer_size + 8;

    // Initialize the SPI bus on VSPI (SPI3)
    spi_bus_initialize(SPI3_HOST, &buscfg, SPI_DMA_CH_AUTO);

    esp_lcd_panel_io_handle_t io_handle = NULL;
    esp_lcd_panel_io_spi_config_t io_config;
    memset(&io_config, 0, sizeof(io_config));
    io_config.dc_gpio_num = LCD_DC,
    io_config.cs_gpio_num = LCD_CS,
    io_config.pclk_hz = 40*1000*1000,
    io_config.lcd_cmd_bits = 8,
    io_config.lcd_param_bits = 8,
    io_config.spi_mode = 0,
    io_config.trans_queue_depth = 10,
    io_config.on_color_trans_done = lcd_flush_ready;
    // Attach the LCD to the SPI bus
    esp_lcd_new_panel_io_spi((esp_lcd_spi_bus_handle_t)SPI3_HOST, &io_config, &io_handle);
    esp_lcd_panel_dev_config_t lcd_config;
    memset(&lcd_config, 0, sizeof(lcd_config));
    lcd_config.reset_gpio_num = LCD_RST;
#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 0, 0)
    lcd_config.rgb_endian = LCD_RGB_ENDIAN_RGB;
#else
    lcd_config.color_space = ESP_LCD_COLOR_SPACE_RGB;
#endif
    lcd_config.bits_per_pixel = 16;

    // Initialize the LCD configuration
    esp_lcd_panel_handle_t lcd_handle = nullptr;

    //
    // Change this from st7789 to your panel's display controller
    //
    esp_lcd_new_panel_st7789(io_handle, &lcd_config, &lcd_handle);

    // Reset the display
    esp_lcd_panel_reset(lcd_handle);

    // Initialize LCD panel
    esp_lcd_panel_init(lcd_handle);
    //
    //  Configure the panel (Different LCD screens may need different options)
    //
    esp_lcd_panel_swap_xy(lcd_handle, false);
    esp_lcd_panel_set_gap(lcd_handle, 0, 35);
    esp_lcd_panel_swap_xy(lcd_handle,true);
    esp_lcd_panel_mirror(lcd_handle, false, true);
    esp_lcd_panel_invert_color(lcd_handle, true);
    // Turn on the screen
#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 0, 0)
    esp_lcd_panel_disp_on_off(lcd_handle, true);
#else
    esp_lcd_panel_disp_off(lcd_handle, false);
#endif
#ifdef LCD_BL
#if LCD_BL > -1
    gpio_set_level((gpio_num_t)LCD_BL,1);
#endif
#endif
}