/mnt/nas/libepaper/include/epaper/internal/internal.hpp

Convert PlaneCount enum to numeric value.

Convert PlaneCount enum to numeric value.Provides compile-time conversion from type-safe PlaneCount to std::size_t for array sizing and iteration.

Parameters

count

The plane count to convert

Returns

Numeric plane count (1, 2, or 3)

Note

This function is constexpr and will be evaluated at compile time when passed a constant expression.

constexpr auto num_planes = plane_count_value(PlaneCount::Two); // 2

#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