klips/esp/cpp/07_lcd-panel/main/display.h

#ifndef DISPLAY_H
#define DISPLAY_H

#include <esp_lcd_types.h>
#include <esp_lcd_panel_ssd1306.h>
#include <driver/i2c_types.h>
#include <driver/i2c_master.h>
#include <unordered_map>
#include <esp_lcd_panel_ops.h>
#include "misc/lv_types.h"
#include "misc/lv_area.h"
#include "display/lv_display.h"
#include "widgets/label/lv_label.h"

#define I2C_BUS_PORT  0
#define LVGL_TICK_PERIOD_MS    5
#define LVGL_TASK_STACK_SIZE   (4 * 1024)
#define LVGL_TASK_PRIORITY     2
#define LVGL_PALETTE_SIZE      8

static const char *TAG = "lcd-panel";

// According to SSD1306 datasheet
// https://www.digikey.com/en/products/detail/winstar-display/WEA012864DWPP3N00003/20533255
// Bit number used to represent command and parameter
#define SCREEN_WIDTH           128  // OLED display width, in pixels.
#define SCREEN_HEIGHT          64  // OLED display height, in pixels.
#define LCD_H_RES              SCREEN_WIDTH
#define LCD_V_RES              SCREEN_HEIGHT
#define I2C_HW_ADDR            0x3C
#define LCD_PIXEL_CLOCK_HZ     (400 * 1000)
#define LCD_CMD_BITS           8
#define LCD_PARAM_BITS         8

// Pin may vary based on your schematic.
#define PIN_SDA                GPIO_NUM_21
#define PIN_SCL                GPIO_NUM_22
#define PIN_RST                -1

struct I2C {
  I2C();

  ~I2C() = default;

  i2c_master_bus_handle_t i2c_bus_;
};

struct ScopedLock {
  explicit ScopedLock() { _lock_acquire(&lock_); }

  ~ScopedLock() { _lock_release(&lock_); }

  // LVGL library is not thread-safe, this example calls LVGL APIs from tasks.
  // We must use a mutex to protect it.
  static _lock_t lock_;
};

template<typename T>
class PanelDevice {
public:
  PanelDevice(size_t width, size_t height) : width_(width), height_(height) { }

  ~PanelDevice() = default;

  [[nodiscard]] size_t get_width() const { return width_; }

  [[nodiscard]] size_t get_height() const { return height_; }

  [[nodiscard]] size_t get_area() const { return width_ * height_; }

  [[nodiscard]] size_t get_draw_buffer_size() const
  {
    // LVGL reserves 2x4 bytes in the buffer to be used as a palette.
    return width_ * height_ / 8 + LVGL_PALETTE_SIZE;
  }

  [[nodiscard]] lv_display_t *create_display() const
  {
    return lv_display_create(width_, height_);
  }

  [[nodiscard]] T &get_vendor_config() const { return vendor_config_; }

  void create_panel(esp_lcd_panel_dev_config_t &panel_config,
                    esp_lcd_panel_io_handle_t io_handle,
                    esp_lcd_panel_handle_t &panel_handle);

private:
  size_t width_;
  size_t height_;

protected:
  T vendor_config_;
};

template<typename T>
void PanelDevice<T>::create_panel(esp_lcd_panel_dev_config_t &config,
                                  esp_lcd_panel_io_handle_t io,
                                  esp_lcd_panel_handle_t &panel)
{
  // If the passed handle is already allocated, delete it.
  if (panel != nullptr) {
    esp_lcd_panel_del(panel);
  }

  // Set the vendor config and allocate a new panel handle.
  config.vendor_config = &vendor_config_;
  ESP_ERROR_CHECK(esp_lcd_new_panel_ssd1306(io, &config, &panel));
}

class SSD1306 : public PanelDevice<esp_lcd_panel_ssd1306_config_t> {
public:
  explicit SSD1306(esp_lcd_panel_ssd1306_config_t ssd_config,
                   int width = SCREEN_WIDTH, int height = SCREEN_HEIGHT);

  ~SSD1306() = default;
};

class Panel {
public:
  explicit Panel(i2c_master_bus_handle_t i2c);

  explicit Panel(const I2C &i2c) : Panel(i2c.i2c_bus_) { }

  ~Panel() = default;

  [[nodiscard]] inline const esp_lcd_panel_t *get() const { return panel_; }

  [[nodiscard]] inline esp_lcd_panel_t *get() { return panel_; }

  [[nodiscard]] inline const esp_lcd_panel_t *
  operator*() const { return get(); }

  [[nodiscard]] inline esp_lcd_panel_t *operator*() { return get(); }

  esp_lcd_panel_io_handle_t io_handle_;

  esp_lcd_panel_handle_t panel_;

private:
  esp_lcd_panel_dev_config_t panel_config_;
};

class Display {
public:
  explicit Display(const I2C &i2c);

  ~Display() = default;

  [[nodiscard]] inline const lv_display_t *get() const { return display_; }

  [[nodiscard]] inline lv_display_t *get() { return display_; }

  [[nodiscard]] inline const lv_display_t *operator*() const { return get(); }

  [[nodiscard]] inline lv_display_t *operator*() { return get(); }

  void set_text(const char *text,
                const char *name,
                lv_label_long_mode_t long_mode = LV_LABEL_LONG_SCROLL_CIRCULAR,
                lv_align_t align = LV_ALIGN_TOP_MID);

  static bool lvgl_flush_ready(esp_lcd_panel_io_handle_t panel,
                               esp_lcd_panel_io_event_data_t *data,
                               void *user_ctx);

  static void lvgl_flush_cb(lv_display_t *display,
                            const lv_area_t *area,
                            uint8_t *px_map);

  static void lvgl_increase_tick(void *arg);

  static void lvgl_port_task(void *arg);

  // For LV_COLOR_FORMAT_I1 we need an extra buffer to hold the converted data.
  static uint8_t oled_buffer_[LCD_H_RES * LCD_V_RES / 8];

private:
  Panel panel_;

  lv_display_t *display_;

  void *buf_;

  std::unordered_map<const char *, lv_obj_t *> objects_;
};

#endif // DISPLAY_H