Gfx.h

#pragma once
#include <FreeRTOS.h>
#include <nrf_font.h>
#include <task.h>
#include <cstddef>
#include <cstdint>
#include "drivers/BufferProvider.h"

namespace Pinetime {
  namespace Drivers {
    class St7789;
  }

  namespace Components {
    class Gfx : public Pinetime::Drivers::BufferProvider {
    public:
      explicit Gfx(Drivers::St7789& lcd);
      void Init();
      void ClearScreen();
      void DrawString(uint8_t x, uint8_t y, uint16_t color, const char* text, const FONT_INFO* p_font, bool wrap);
      void DrawChar(const FONT_INFO* font, uint8_t c, uint8_t* x, uint8_t y, uint16_t color);
      void FillRectangle(uint8_t x, uint8_t y, uint8_t width, uint8_t height, uint16_t color);
      void FillRectangle(uint8_t x, uint8_t y, uint8_t w, uint8_t h, uint8_t* b);
      void SetScrollArea(uint16_t topFixedLines, uint16_t scrollLines, uint16_t bottomFixedLines);
      void SetScrollStartLine(uint16_t line);

      void Sleep();
      void Wakeup();
      bool GetNextBuffer(uint8_t** buffer, size_t& size) override;
      void pixel_draw(uint8_t x, uint8_t y, uint16_t color);

    private:
      static constexpr uint8_t width = 240;
      static constexpr uint8_t height = 240;

      enum class Action { None, FillRectangle, DrawChar };

      struct State {
        State() : busy {false}, action {Action::None}, remainingIterations {0}, currentIteration {0} {
        }

        volatile bool busy;
        volatile Action action;
        volatile uint16_t remainingIterations;
        volatile uint16_t currentIteration;
        volatile FONT_INFO* font;
        volatile uint16_t color;
        volatile uint8_t character;
        volatile TaskHandle_t taskToNotify = nullptr;
      };

      volatile State state;

      uint16_t buffer[width]; // 1 line buffer
      Drivers::St7789& lcd;

      void SetBackgroundColor(uint16_t color);
      void WaitTransferFinished() const;
      void NotifyEndOfTransfer(TaskHandle_t task);
    };
  }
}