/mnt/nas/libepaper/include/epaper/drivers/driver.hpp

Display mode enumeration.

Display mode enumeration.Defines the color/grayscale mode a display can operate in. Each mode implies specific bits-per-pixel, color capability, and hardware buffer requirements.

Mode Characteristics:

• BlackWhite: 1 bpp, 2 colors, single buffer
• Grayscale4: 2 bpp, 4 gray levels, single buffer
• BWR/BWY: 2 bpp, 3 colors, dual-buffer (black/white + red/yellow)
• Spectra6: 3 bpp, 6 colors, single 3-bit buffer

Mode Selection Guidelines:

• Use BlackWhite for fastest refresh and maximum contrast
• Use Grayscale4 for anti-aliased text or smooth gradients
• Use BWR/BWY for highlights, warnings, or accent colors
• Use Spectra6 for colorful diagrams or illustrations (slower refresh)

Note

Not all modes are supported by all drivers. Check driver_traits<Driver>::max_mode and driver_traits<Driver>::supports_grayscale before creating display.

// Query mode capabilities
DisplayMode mode = DisplayMode::BWR;
auto bpp = bits_per_pixel(mode);      // Returns 2
bool has_color = is_color_mode(mode); // Returns true
auto planes = num_planes(mode);       // Returns 2
 
// Mode-specific display creation
if (driver_traits<EPD27>::max_mode >= DisplayMode::BWR) {
  auto display = create_display<EPD27>(device, DisplayMode::BWR);
}

See also

bits_per_pixel(), is_color_mode(), num_planes(), driver_traits

#pragma once
 
#include <cstddef>
#include <cstdint>
 
namespace epaper {
 
enum class DisplayMode : std::uint8_t {
  BlackWhite, 
  Grayscale4, 
  BWR,        
  BWY,        
  Spectra6    
};
 
[[nodiscard]] constexpr auto bits_per_pixel(DisplayMode mode) noexcept -> std::uint8_t {
  switch (mode) {
  case DisplayMode::BlackWhite:
    return 1;
  case DisplayMode::Grayscale4:
  case DisplayMode::BWR:
  case DisplayMode::BWY:
    return 2;
  case DisplayMode::Spectra6:
    return 3;
  }
  return 1; // Default fallback
}
 
[[nodiscard]] constexpr auto is_color_mode(DisplayMode mode) noexcept -> bool {
  switch (mode) {
  case DisplayMode::BWR:
  case DisplayMode::BWY:
  case DisplayMode::Spectra6:
    return true;
  default:
    return false;
  }
}
 
[[nodiscard]] constexpr auto num_planes(DisplayMode mode) noexcept -> std::size_t {
  switch (mode) {
  case DisplayMode::BlackWhite:
  case DisplayMode::Grayscale4:
    return 1;
  case DisplayMode::BWR:
  case DisplayMode::BWY:
    return 2;
  case DisplayMode::Spectra6:
    return 1; // Spectra6 uses single 3-bit buffer
  }
  return 1;
}
 
} // namespace epaper