internal.hpp

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#pragma once
 
#include "epaper/core/types.hpp"
#include <cstddef>
#include <cstdint>
#include <utility>
 
namespace epaper::internal {
 
inline constexpr std::size_t PLANE_COUNT_ONE = 1;
 
inline constexpr std::size_t PLANE_COUNT_TWO = 2;
 
inline constexpr std::size_t PLANE_COUNT_THREE = 3;
 
enum class PlaneCount : std::uint8_t {
  One,  
  Two,  
  Three 
};
 
[[nodiscard]] constexpr auto plane_count_value(PlaneCount count) noexcept -> std::size_t {
  switch (count) {
  case PlaneCount::One:
    return PLANE_COUNT_ONE;
  case PlaneCount::Two:
    return PLANE_COUNT_TWO;
  case PlaneCount::Three:
    return PLANE_COUNT_THREE;
  }
  std::unreachable();
}
 
inline auto transform_coordinates(std::size_t x, std::size_t y, std::size_t width, std::size_t height,
                                  Orientation orientation) -> std::pair<std::size_t, std::size_t> {
  switch (orientation) {
  case Orientation::Portrait0:
    // Identity transformation - no rotation applied
    // Logical coordinate system matches physical display layout
    return {x, y};
 
  case Orientation::Landscape90:
    // 90° clockwise rotation:
    // - Original top-left (0,0) → new top-right (width-1, 0)
    // - Original top-right (width-1, 0) → new bottom-right (width-1, height-1)
    // Transformation matrix: [x'] = [0  -1] [x] + [width-1]
    //                        [y']   [1   0] [y]   [0]
    // Simplified: x' = width-1-y, y' = x
    return {width - 1 - y, x};
 
  case Orientation::Portrait180:
    // 180° rotation:
    // - Original top-left (0,0) → new bottom-right (width-1, height-1)
    // - Original center stays at center
    // Transformation matrix: [x'] = [-1  0] [x] + [width-1]
    //                        [y']   [0  -1] [y]   [height-1]
    // Simplified: x' = width-1-x, y' = height-1-y
    return {width - 1 - x, height - 1 - y};
 
  case Orientation::Landscape270:
    // 270° clockwise (90° counter-clockwise) rotation:
    // - Original top-left (0,0) → new bottom-left (0, height-1)
    // - Original bottom-right → new top-right
    // Transformation matrix: [x'] = [0   1] [x] + [0]
    //                        [y']   [-1  0] [y]   [height-1]
    // Simplified: x' = y, y' = height-1-x
    return {y, height - 1 - x};
 
  default:
    // Fallback for any unexpected orientation values
    // Returns identity transformation for safety
    return {x, y};
  }
}
} // namespace epaper::internal