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

#ifndef DISPLAY_H
#define DISPLAY_H


#include <widgets/label/lv_label.h>

#include <unordered_map>

#include "time_keeper.h"
#include "panel.h"

#define LVGL_TICK_PERIOD_MS    5
#define LVGL_TASK_STACK_SIZE   (4 * 1024)
#define LVGL_TASK_PRIORITY     2

class Display {
public:
  //
  // CONSTRUCTORS

  Display(const Display &) = delete;

  Display(Display &) = delete;

  Display &operator=(Display &) = delete;

  /**
   * Construct a new Display using an IPanelDevice.
   *
   * @param device An object that implements the IPanelDevice interface.
   */
  explicit Display(IPanelDevice &device);

  ~Display() = default;

  //
  // GETTERS

  /**
   * Getter for accessing LVGL display handle.
   *
   * @sa ScopedLock for calling custom LVGL API's not implemented by Display.
   */
  [[nodiscard]] inline const lv_display_t *get() const { return lv_display_; }

  /**
   * Getter for accessing LVGL display handle.
   *
   * @sa ScopedLock for calling custom LVGL API's not implemented by Display.
   */
  [[nodiscard]] inline lv_display_t *get() { return lv_display_; }

  /// Dereference operator for accessing LVGL display handle.
  [[nodiscard]] inline const lv_display_t *operator*() const { return get(); }

  /// Dereference operator for accessing LVGL display handle.
  [[nodiscard]] inline lv_display_t *operator*() { return get(); }

  //
  // LVGL OPERATIONS

  /**
   * Create a LVGL label with some given text on the current display.
   * The name of the object can be reused to change text on this label later.
   *
   * @param text Text to write to the display.
   * @param name Name for the LVGL label object associated with this text.
   * @param long_mode LVGL long mode for text wider than the current display.
   * @param align LVGL alignment to use for placing the label on the display.
   */
  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);

  //
  // TYPE DEFINITIONS

  /**
   * Obtains LVGL API mutex lock for the duration of local scope.
   *
   * LVGL library is not thread-safe, this example calls LVGL APIs from tasks.
   */
  struct ScopedLock {
    explicit ScopedLock() { _lock_acquire(&lv_lock_); }

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

    /// Mutex used to protect LVGL API calls.
    static _lock_t lv_lock_;
  };

  //
  // PUBLIC STATIC MEMBERS

  /// Public static TimeKeeper for managing ESP timers across all displays.
  static TimeKeeper timers_;

private:
  /// Registers LVGL draw buffers for this display.
  void register_draw_buffer();

  /// Registers LVGL ticker timer callback for rendering this display.
  static void register_lvgl_tick_timer();

  static bool lvgl_flush_ready_cb(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_cb(void *arg);

  [[noreturn]] static void lvgl_port_task(void *arg);

  //
  // PRIVATE MEMBERS

  /// Panel associated with this Display.
  Panel panel_;

  /// LVGL display handle.
  lv_display_t *lv_display_;

  /// LVGL draw buffer associated with this Display's lv_display_t.
  void *lv_buf_;

  /**
   * LVGL object handles stored in the LVGL screen associated with this Display.
   *
   * @sa Display::set_text
   * @sa lv_display_get_screen_active
   */
  std::unordered_map<const char *, lv_obj_t *> lv_objects_;
};

#endif // DISPLAY_H